Choosing the right type of chain lube can make a big difference in your ride.  It effects everything from noise and cleanliness to efficiency and drivetrain longevity.  Everybody who has been around the sport for a while has their preferred type of chain lube but might not even know why that is what they use.  Unfortunately a lot of people are getting this decision wrong because it is based on their local bike shop mechanic’s opinion that was passed down from another mechanic, rather than based on any kind of research or technology.  We will dive into where we think each type of lubricant belongs and the benefits and drawbacks of them.

Dry Chain Lube

Dry lube has long been a favorite recommendation for riding in dry conditions because it is “cleaner” than other options.  Dry lube is perfect for the garbage can and just about nowhere else.  Dry lube picks up less dirt that a wet lube because it is typically 90%+ carrier and less than 10% lubricant.  Even then the lubricant is typically not great.  It is often just PTFE powder that is hopefully left on the chain.  You can read more about our thoughts on PFAS chemicals like PTFE on our blog.

This “clean” ride is really because once all that carrier flashes away, there is virtually zero lubricant on the chain, so you are getting an awful lot of metal-on-metal friction.  This leads to premature wear, short longevity, it is loud, and extremely poor performance in friction testing.  Dry Lube has no place in cycling and the cleanliness promised can be had in much better ways.

Wet Chain Lube

Wet lube has long been recommended by your local bike shop for when you ride in wet conditions, hence the name.  It is the best oil-based option out there.  Wet lubes are not all created equal and can range from a low-quality oil with PTFE powder all the way to high quality synthetic oils with some of the lowest friction additives known on the planet and everywhere in between.  If you want to see some of our head to head tests, you can check out our Chain Lube Shootouts. 

The benefits of using an oil-based lube are that you can simply drip in on the chain, wipe off excess, and go ride.  The cleaner the better, but there is no need to do any in depth cleaning and you can get a lot of riding between application cycles.  The downside of oil-based lubes is that it attracts dirt.  Dirt will stick to oil (no matter what a marketing department tells you) and will ultimately turn that oil into a grinding paste of sand, dirt, and oil. 

Wet lube is the perfect option if you are going to regularly ride in the rain and don’t want to spend a ton of time cleaning after.  You can simply wipe down the chain with a bit of degreaser and re-lube after a wet ride.  It is also a good option for somebody who doesn’t want to mess with the cleaning process required for wax.

Hot Wax

Melting down paraffin wax has been around for quite a long time but has always been looked at looked at as way too much work for no real gain.  A recipe was published by a major media outlet some time ago and a company was born.  There was still not much of an adoption outside of some really dedicated cyclists because the barrier to entry was cleaning and removing the chain from the bike.  It wasn’t until the last couple of years that more independent testing of chain lubes came out and highlighted how much faster wax was than any other option we had. 

We knew here at SILCA that we had a formula that would be even faster than what was out there, and we had customers asking us to release the hot melt wax version of our SuperSecret Chain Lube, so we did.  We knew it was great at reducing friction and keeping the chain clean, but we were surprised how many other people would be willing to clean their chain to a necessary level.  Hot Wax is the best lubricant for an hour record which says it is the absolute lowest friction option when there is no contaminant present.  It is also great for dirty conditions as the additional wax on the chain will flake off and bring that dirt with it, so it stays clean for a very long time.  This eliminates the grinding paste that you can get with oil-based lubes.

While hot wax is certainly the preferred lubricant in almost every single scenario, it isn’t without some downsides as well.  The biggest one is the cleaning process.  Removing the chain and multiple baths of harsh chemicals are required to strip the chain then you must melt the wax and dip the chain.  Previously you would have to have a dedicated slow cooker to melt the wax and SILCA has overcome that with a Sous-vide bag that allows you to melt the wax repeatedly without having a dedicated kitchen appliance, but the cleaning has still been a hesitation point for some. 

Cleaning is often looked at as a barrier to wax or downside, but after the initial cleaning it is very much a positive.  Ride on a dusty trail with oil and it will take a ton of work to get the chain clean, but with wax all you need to do is wipe with a clean rag.  It might not even need to have more lubricant applied since you didn’t have to remove the lubricant to clean the dirt off the chain.  This is a huge plus in our opinion and very much worth the little extra effort up front.  That up front work is something we are working on as well, so stay tuned!

With the rise of these ultra-endurance events, we are getting a lot of questions about relubing a chain in the middle of an event.  If you have an extremely dirty 200-mile ride wax will struggle to make it the entire distance.  Some will recommend applying our next type of lubricant with emulsified wax, but we recommend applying a wet lube over wax because the emulsifiers in drip wax can bring any remaining wax out of the chain and make any issues you are having worse.  This longevity is probably a downside for some ultra-endurance athletes, but we think the efficiency advantages are certainly worth applying a new lubricant if that is needed.

The other downside of wax is that it doesn’t get along with water all that well.  Since there is no oil to repel water from the metal, it can lead to rust if you ride in the rain and leave the bike overnight.  A waxed chain needs to be cleaned post ride if there is much water then re-lubed.  You can clean it off with a gear wipe or clean rag, then drop it back in your hot wax or use an emulsified wax like we will touch on below.

Drip Wax

Drip wax is a new category as something that we would recommend.  SILCA was the first company to be tested by independent testing company, Zero Friction Cycling, to be able to successfully penetrate the chain to prevent friction.  This opened a whole new world and now there are a few different options for riders who want to drip wax on their chain.

The benefit of drip wax is that you get most of the cleanliness of a hot melt wax without having to take the chain off your bike for application.  It is extremely low friction when done correctly and keeps your chain extremely quiet.  It is also perfect for riders using hot melt wax to top up their chain between hot melt applications. 

The downsides of drip wax are that they aren’t quite as clean as hot melt, not as quiet, and still requires an intense cleaning, and you still have the slight issue with water.  In our opinion these are small downsides for the benefits of lower friction, cleaner drivetrain, and the silence on the bike, but they are certainly worth noting.

Summary

Chain lubrication is certainly a rapidly evolving topic that we are looking at differently than we did 10 or 15 years ago.  We are certainly fans of wax here at SILCA and would recommend it for almost every application and are working hard to continue developing new formulas that are better and better than we have ever seen before. 

Standard Cleaning

One of, if not the biggest benefits to waxing your chain is how clean it runs and how easy it is to keep that way!  When you get done with a ride, you can simply wipe off any debris from the chain with a microfiber towel or a gear wipe.  

 

If you had a dry, dusty ride, you will want to remove that dust, but you can be confident that the wax is still in between the inner and outer plates, which is where the friction is happening.  

 

You will not want to use another degreaser on the chain as that residue could be left on the chain and cause future wax not to stick as well.  The degreaser in the gear wipes, however, flashes completely, so it won't cause an issue.

If you had a wet ride, please see the section below titled "Wet Ride Maintenance" for directions for maintenance in this specific scenario.

 

Standard Re-Wax/Re-Lube Intervals

When it comes to knowing when to re-wax your chain, there are a few variables that come into play. The first variable is what type of wax you have applied to your chain. Please see the chart below for our estimated ride time/distance that you can achieve with our different additives. The longevity of your wax can also be increased by applying Super Secret Chain Lube. The addition of this lube can add up to an additional 300km of riding on your current hot wax treatment per use. Super Secret can be applied one drop per link after every ride, after every week, or as often as you see fit. If you are unsure if it is time for a rewax, pay a little extra attention to your chain during your next ride. If it sounds louder than usual and is not running as smoothly, it is probably time for you to do a re-wax or at least apply Super Secret! 

 

 

 

Wet Ride Maintenance

How to maintain your waxed chain after a wet ride starts with our favorite answer: it depends.  First, we will cover how to handle a little bit of water; maybe you got a light rain for a few minutes, ran through some wet roads, etc.  

 

For these light rain situations, simply try to get the chain dry quickly, wipe down with a gear wipe as this will help some of that water flash off, and reapply either Super Secret Chain Lube or Hot Wax. Super Secret can also help your hot wax preform better in these conditions! If you have access to an air compressor, quickly blowing out the chain is a great way to remove all that water.

 

Now, for those long driving days where you are out for hours at a time, it is very important that you get that drivetrain dried off as quickly as possible.  If the chain sits, there is no oil to remove water, so the chain can start to develop surface rust.  Blow out the chain or wipe it dry with a microfiber towel.  Then you are going to want to add your Super Secret Chain Lube or Hot Wax treatment to help the last bit of moisture be driven out.  This will make sure your chain is ready to go for the next ride.

 

If you do get a bit of surface rust on your chain, don't worry; it's not ruined.  It will typically rub right off with a gear wipe and might just take a little more effort for a brush.

Mid-Ride Lubrication for Muddy/Wet Rides

A waxed chain should give you 200-250 miles pretty reliably per application, assuming good conditions.  If it is wet and muddy, that can be shorter.  For an event like Unbound 200, even if it's going to be a rainy day, we recommend running a waxed chain as it is going to be the best at repelling as much mud as possible and is going to lead to the lowest friction.  

 

With that being said, you are not going to get 200 miles out of a mud-filled day like we saw in 2022.  This is where a high-quality oil-based lubricant like Synergetic comes into play.  An emulsified wax like our Super Secret Chain Lube, or any other brand's offering, can't be used effectively mid-ride.  The same additives that make that wax a liquid need to evaporate for it to be effective.  Adding those mid-ride can actually have the opposite of the intended effect by emulsifying the wax that is on the chain and removing all lubricant from the chain.  

 

For those reasons, we recommend using a high-quality wet lube.  The oil will penetrate and quiet the chain while providing the needed lubrication.  Since oil and wax don't mix well, you will need to strip the chain when you get home if you want to wax again.  This is a boiled water, degreaser bath, acetone, and re-wax process.

Cleaning a Bike with a Waxed Chain

Since we know waxed chains and water aren't best friends, how do you go about washing your bike after a dirty ride?  We can go ahead and assume if your frame is pretty dirty, your drivetrain likely is too.  In this case, go ahead and wash your bike like normal, with the exception of being careful not to use any soap or cleaner on the drivetrain.  This is to make sure that the wax has clean metal to stick to.  

 

You can rinse the chain with water, dry it off, and either take it off to hot wax or apply super secret as soon as the bike is dry.  

 

Another great option is to clean your chain, as we talked about above, but to use a waterless wash like our Ultimate Waterless Wash.  This will help clean your frame and leave behind a protective ceramic coating.  

 

For the ultimate in deep cleaning, our favorite tip is to remove the chain before you start cleaning and then go about your cleaning process on the frame and clean the chain completely separately.

Chain Maintenance Video

For those of you who would rather see waxed chain maintenance on video, below you can see our instructional video on how to maintain your waxed chain so it lasts longer, runs cleaner, and stays just as fast as day 1.

Thank You for Choosing Silca's Ultimate Tubeless Sealant! 

We are super excited about our new Ultimate Tubeless Sealant! We can't wait for you to try it and hope that you love it as much as we do! We know that trying a new product on your bike can be nerve-wracking, so here are some common questions that we have seen and our answers to help clear some things up for you, and some very helpful videos produced by Josh:

What is the difference between your new sealant and your old sealant?

This is a great question! Our new sealant is the first on the market that is a blend of natural and synthetic latex. This will give you the benefits of both. This has more and smaller carbon fibers than our previous sealant that allow it to be injected but also does not decrease the sealing power. This is a one-step product and does not require a replenisher like our old sealant. This sealant can also last for 6 months before you need to start worrying about it. 

Can I use your new sealant in a tire that previously had your old sealant?

Yes! You may use our new sealant in a tire that previously had a different sealant in it. We suggest that you remove the tire and clean out as much of the old and dried sealant as you can, especially any large sections and especially on the bead of the tire. What we do not recommend is mixing our old sealant (or any other brand of sealant) with our Ultimate sealant.

How does this sealant compare to other brands I have seen?

Our Ultimate Tubeless Sealant was tested for over two years before it was launched to ensure we have perfected a top-of-the-line formula for you. We have also put our sealant through rigorous field testing by all of our athletes from all over the world. Through this process and these tests, we believe that we have created one of, if not the best, sealant in the market when it comes to consistent and impressive results in sealing ability. 

The Ultimate Tubeless Sealant Story

If you would like to learn more about the research, development, and thought process behind this product, please check out this blog post! 

Ultimate Tubeless Sealant FAQ's

How to use the rewards points

To use your points, you need to redeem them for a discount code, which you can do here: SILCA Rewards. If you aren't already logged in when you go to this link, then it will redirect you to your account page when you log in. If this happens, just click the "rewards" tab, which is next to the "shop" and "resources" tabs. Once you're logged in, you'll be able to see what rewards are available for you to redeem. 

How to Use Chain Stripper

Our Chain Stripper is a game-changing product that eliminates the need for all the harsh chemicals previously needed to strip a chain down to bare metal.  If you want all the benefits of a waxed chain, like the increased life of the drivetrain, the cleanliness, and the out-and-out speed, removing the grease, grime, and lubricants from your used chain is key. 

The steps are simple:

1. Remove the chain from its packaging and place it in a jar or bottle with a lid.

2. Add a few ounces of Chain Stripper to your container (enough to cover most of your chain). 

3. Shake for about 30 seconds, then allow the chain to sit submerged for at least 5 minutes.

4. Shake again for about 30 seconds.

5. Remove the chain and rinse it thoroughly with water to remove all the encapsulated grease that came out of the chain (we recommend rinsing 2-3 times).

6. Place in Hot Melt Wax and allow it to sit, fully submerged,  until all of the bubbles stop coming up, as this is the water being replaced by wax in the chain.

What We are Calculating

Cincher vs. Tubeless vS. Tubular

Consistency in Our Findings

Resources for Tubeless Installation and Replenishment

We are super excited that you have decided to try our Ultimate Tubeless Sealant. Setting up tubeless for the first time can often seem daunting. But we promise it is not as difficult as it may sound. To help this process go smoothly for you, we have compiled this library of resources for you to reference and learn from. 

Installing Tubeless with Sealant Injector

Installing Tubeless Using Pour Method

If you are looking to install tubeless without our sealant injector, please reference this instructional blog post or the video below: 

How to Replenish your Tubeless Sealant

If you have already set up your tires to be tubeless with our ultimate tubeless sealant and are due for a replenishment, please check out this handy blog post for instructions! 

The Torque tube shows a live reading, meaning that you will not need to preset it before use. Just start applying force to the tool, and the arrow will point to the amount of torque being applied! You can see this in this video here: https://www.youtube.com/watch?v=2a_KWg6NxQc

We do ship to most countries, however, there are a few that we are unable to send to.

To review the countries we currently don't ship to, please see below:

Azerbaijan

Belarus

Russia

Ukraine

North Korea

Please note that international shipments can take longer to ship.

If you have been waiting for more than 15 days to receive your order, please get in touch with our team to investigate the issue.

How important can tire pressure really be?

We receive a lot of great comments and emails through the website and one of the most common questions is something on the order of 'how important can tire pressure really be?'  This often comes in the form of a statement trying to refute the idea of our expensive floor pump something like "I have a 4-year-old BrandX that cost me $80 and it does everything perfectly, your expensive pump is stupid and unnecessary."  We enjoy reading these as they generally include colorful language, but what has really become clear to us over the last year is the belief that tire pressure is more or less non-critical, most people seem to believe that tire pressure is a topic that has been 'solved,' just put it at the MAX on the sidewall and go!

Fortunately for us, Pro-Tour mechanics, teams, pro Cyclocross mechanics, national track teams, and many others have understood this and have been utilizing our 'stupid and unnecessary' pump to win dozens of championships and events around the world, so we ask ourselves, why the discrepancy between conventional wisdom and pro-level experience?

First, it isn't just cycling, at the top levels of pro racing, road, MTN., and cyclocross but even more so: motorcycle, IndyCar, F1...tire pressure is one of the most difficult and time-consuming optimization problems faced by engineers and teams.  In Formula1 for example, CFD, FEA, and other computer technologies allow the engineers to build entire virtual engines, predict horsepower, torque, temperatures, model aerodynamics with incredible accuracy, and even model suspension kinematics including damping rates...however, to complete the virtual racecar, requires a series of data plots from the tire manufacturers which can only be created by producing very real prototype tires that are actually tested in laboratories at varying pressures!  Make no mistake, the dynamics of a real tire are incredibly complicated and are far from 'solved'.  

How and why does tire pressure matter so much?

So how and why does pressure matter so much?  For one, the tire is the ONLY thing connecting the bike (or racecar for that matter) to the road.  ALL forces must be translated through the tires, which serve as both traction device to the road, suspension to the bicycle, and protection to the rim, and do so in multiple axes as the tire is capable of deforming and squirming not just vertically, or laterally but fore-aft and rotationally.

It is through these deformations that the tire forms the contact patch with the road.  This patch allows you to put traction down to drive forward, provides the negative of that force to allow braking, and handles the lateral forces that allow cornering.  During this time the casing deforms around small and large imperfections in the road to provide compliance for the rider, while maintaining contact patch consistency.  Anyone who has ever tried inline skating on a rough road knows how critical this is, those hard urethane wheels that are so efficient on smooth surfaces are both slow and nearly impossible to control as they bounce over increasingly rough surfaces.

Ultimately, the reason tire pressure doesn't get much thought or publicity is that it isn't an easily solved problem, and the 'answer' will vary from rider to rider, and course to course.  Most of what we love to talk about in cycling are Maximize and Minimize type problems, these have the easiest marketing message, are most easily conveyed, and are most easily remembered: Weight: minimize, stiffness: maximize, Aerodynamics: minimize, compliance: maximize, etc.  (Interestingly these are the same things we love to discuss when we buy new products, in effect, Max and Min can be bought). However, tire pressure is an 'Optimize' type of problem and one that has numerous variables including rider weight, road surface roughness, rider weight bias, tire width, rim bead width, tire diameter, tire construction, and more!  Pressure isn't an advantage that can be bought, it is something that must be learned, experienced, and understood, potentially representing an advantage (or disadvantage) that cannot simply be purchased.

STEP 1: DEGREASE THE DRIVETRAIN

How Much Sealant to Add for Initial Tubeless Set Up

If you are adding Ultimate Tubeless Sealant to a new tire, we do recommend that you add more than you would when doing a refill. New tires often "soak up" a fair amount of sealant when first introduced to it. Please reference the chat below to help determine the amount of sealant you should be adding:

How Much Sealant to Add for Refills 

Please see the chart below for our recommended minimum amount of sealant for your tire size:

We’re sorry your item(s) have damage!

Some items break during shipment. We’ll do our best to help.

Please email our team with an image of your damaged item for further assistance.

While we may not be able to guarantee your exact order is replaced due to potential stock issues, we’ll be sure to resolve the situation as best we can!

Asymmetry

Asymmetry plays a unique roll most everything from the workings of the universe codified in what's known as Thermodynamic Time Asymmetry to the way the human brain processes and makes decisions regarding risk and reward.

For most of my career, I've been out to exploit gaps in the knowledge of the sport of cycling, particularly gaps in areas where two or more systems overlap each other creating unique optimization problems with asymmetric behaviors. I like to visualize these problems as a hockey stick. If your worldview is sufficiently small and you are on the handle of the stick, the world appears to be linear in both directions and if you are sufficiently small and on the blade, then the world appears to be consistently curved and steep in both directions.. but you have to see the whole picture to realize that the two elements of the stick come together to form a whole which contains all the elements.

 

In many ways, this is a nice metaphor for the work that's been done to push technology forward in our beautiful sport. For years, performance was viewed purely as the human motor, then it focused on the weight of the machine, then on the friction of the machine, then stiffness and later on the aerodynamics of the machine. After 100 years of progress, we can now see the entire machine as a complex system, one that is full of hundreds of these hockey stick shaped optimization problems.

 

 

Two of my favorites involve tires, rolling resistance, and risk. When we were developing the first carbon aero wheels for Roubaix, we conducted dozens of tests on the cobbles of both the Arenberg Forest as well as the Carrefour del Arbre and we noticed something fascinating in the data... riders went faster for the same power as tire pressure was reduced. Test after test, reduce the pressure, and speed increases. Think of this as the long handle of the hockey stick... 100psi.. not good, 90psi, after, 80, psi faster, 70psi, faster... sense the trend? Then suddenly an asymmetry presents itself: 60psi, broken wheels.  (Note graph below is cobble simulated data and not team data.. so wheel failure occurs at 50psi)

 

I like to analogize this to the story of Icarus. When Icarus and Daedalus escape the Palace of King Minos on Crete Daedalus warns Icarus not to fly too close to the sun as his wings may melt, while also not flying too close to the sea as his wings may become heavy with mist... This optimization of Roubaix tire pressures is similar to the asymmetric challenge faced by mountain, trials, CX, and gravel racers around the world in key events: 'How low are you willing to go?' The risks here are highly asymmetric, 3psi too high, and you may not be as fast as your rival, yet 1psi too low and you may be standing on the side of the road waiting for 2 spare wheels while the race rides away from you!

 

Similarly, we find another Icarus asymmetry in road and track racing at much higher pressures. This is analogous to Icarus flying too close to the sun! While we were all brought up to believe that higher pressures are better on road and track, testing has shown this not to be the case. Rolling resistance will decrease as pressure increases, but eventually, the pressures become high enough that the tire begins to ride 'over' the bumps rather than 'through' the bumps, and while the deflection of a tire casing is more than 90% efficient, the lifting and dropping of a bike and rider over each of those thousands of bumps is more like 30-40% efficient. So just as we see in the cobble analogy, even decent pavement can become problematic as pressures become too high!

 

 

 

 In this case, the asymmetry is opposite that of the cobble story. The rolling resistance on pavement decreases as pressure increases, slowly and steadily.. 60psi is OK, 70psi is better, 80psi is better still, 90 is really good and suddenly 100psi is .. wait? worse? Yes. Now the penalty, in this case, isn't standing on the side of the road with broken equipment, but the hockey stick is working against us! Our testing shows that while 5psi below optimal pressure for a given surface may cost you 1 watt, 5psi above the optimal pressure may cost you 3-4 watts.

 

This is the type of optimization problem that is highly favorable to those with the greatest amount of knowledge and data. One which favors those who can make the best decisions based on complex combinations of data sets... imagine, the race of Paris Roubaix 2018 if you are the team of Peter Sagan... 55km of paving in 29 sectors in a race of 257km. So we have another optimization problem with asymmetry: do you optimize for the 200km of pavement? Or the 55km of Pave? How do you best blend the two?

 

 

 

Now I've been directly involved with this question for 7 of the last 8 winners of this race.. and the answer is that a larger tire allows for more leeway in both directions.. last year we ran 32mm tires labeled as 30mm and that gives another 4-5% rolling advantage at the same pressure on the smooth pavement sectors, while also giving 8-9% extra distance between the rim edge and the cobbles at the low end on the terrible cobble sectors. Of course, we still have to determine where in this range to optimize further.. as creating extra advantage at both ends then also needs to be further developed into more advantage!

In nearly every facet of performance there exist dozens if not hundreds of these asymmetric optimizations, we will be covering this topic even further at MarginalGainsPodcast.cc where we will also be discussing the asymmetry of human decision making when faced with this type of data.

THE DIRECTION OF WRAP IS KEY.

There are only 3 contact points between the rider and the bike. 

 - Saddle

- Pedals

- Bars

Start with the wrap to the outside starting from the drops, this keeps the tape from sliding down over time, while also making sure that the forces from your hands during riding are acting to tighten rather than loosen the tape.

The aluminum end plugs have an awesome expander that keeps them in place no matter what, it's a great feature.

The SILCA tape combines a unique and very springy foam material that is super light with a top coating that is stretchy and tacky like nothing else.  The Piloti tape can be wrapped to expose one of two different textures, I prefer the higher grip texture which has more grooves and works well with or without gloves.

I prefer to wrap my own bars, it gives me a deeper connection to the bike, and it also makes me happy to look down and see my own handiwork.  I think everybody likes their own method of wrapping the best, I know I sure do.

The Butterfly piece on the SILCA tape is extra nice, it allows an over/under wrap at the lever without everything becoming too thick or the hoods sticking out.  A few extra minutes spent here will be worth it over the rest of your season!

After a deep clean and new tape, the bike feels brand new again!

Tricks to Seating a Tubeless Tire

What to do if your Super Secret Chain Lube has a Change in Texture

What are the advantages of using Endurance Chip and Speed Chip?

Endurance Chip and Speed Chip are our wax blend additives that allow each rider to customize their wax blend to fit their specific needs. If you are a rider who is looking to get more distance ridden between waxings, Endurace Chip was made for you! If you are a rider who is looking to maximize your speed and efficiency, Speed Chip is for you! Please see the chart below for information on the performance of these addatives: 

If you have any questions about what specific mix will work best for you or any events that you may be participating in, please reach out to us, and we will do our best to provide you with a customized recommendation.

How to Use Wax Additives 

Once you add Speed Chip or Endurance Chip to your wax pot once, any wax in your pot will have the advantages of this chip for all future waxings. All of our wax additives may be used at the same time in the same pot of wax. If you are using multiple additives in your blend, please follow the heating instructions for the additive with the highest required temperature. 

Endurance Chip: 95C

Speed Chip: 95C

Strip Chip: 125C

See Strip Chip Specific Instructions Here

Once your order has been placed and processed, you will receive a confirmation email with your order details. This email will include a tracking number and a link to our tracking page.

Click on the tracking number link or enter the tracking number into our tracking page.

Tracking information may not be immediately available after your order is placed. It can take up to 48 hours for the number to become active in our system. We only ship out Monday - Friday, 8 am - 5 pm. If you don't see any updates right away, please be patient and check back later.

In Part 1, we discussed actual tire width, specifically how it was affected by the bead seat width of the rim, and also how it was generally NOT equal to the number printed on the sidewall.  

In part 2, we are going to look specifically at how tire width affects stiffness by measuring the vertical stiffness (more specifically, the vertical force at a given displacement) of various mounted and inflated tires.

Is wider stiffer/Harsher?

The initial design of this test was to show that larger-diameter tires are actually Stiffer/Less Comfortable when inflated to the same pressure.  This is due to an effect known as ‘Casing Tension’ and is caused by the internal air pressure acting on a larger surface area in the larger tire.  Essentially, the same pressure acting on more surface area makes for higher casing tension.  The best explanation of Casing Tension we’ve seen was done by our friends at FLO Wheels and can be found HERE if you are interested!

For this part of the discussion, we used an Instron machine to look at the force required to deflect tires at various pressures and widths.  To keep things (relatively) simple, we will refer to the tires by the number printed on the sidewall while also mentioning the pressure used and the rim bead seat width.  You can refer back to the chart in Part 1 if you are interested in the actual sizing for comparison to other tire models and brands. 

An Instron machine is a large H-shaped piece of lab equipment that can drive the center beam of the H up and down with extreme accuracy while measuring either tension or compression on an object in the middle.  Chances are that if you ever see anybody say that part A is X% stiffer/stronger/more elastic than part B, the numbers were generated in one of these machines.

The Test Machine with 8mm Anvil In Place (photo not taken during actual testing)

For this test, we used a solid steel wheel-holding fixture bolted to the base of the machine and 3 different test anvils to push on the tires.  We tested tire stiffness against a Flat Surface, an 8cm radius Cobble Surface, and an 8mm radius Bump Surface.

Below are the actual measurements of the 3 Tires on the rim used for testing.  Please note that we will continue to use the size printed on the casing to refer to the tires as it is much less confusing than using the actual measurements, though the actual measurements will be important for determining optimal pressures.  Also, 17c is the industry standard for a bead measuring 16.5 mm -17.5 mm.  The Rim we are using is a 17c rim which measures 17.5mm, please consider them interchangeable for the purposes of this test.

Flat Surface Data

Our first study was just to look at the differences between 3 different tire widths on the same wheel with a 17.5mm inner bead at the same pressure.

23, 25, and 28mm Tires on the Same 17.5mm Bead Width Wheel – Flat Surface

The first thing to notice here is that the wider tire (28mm) is actually Vertically Stiffer than the 25mm tire, which is in turn stiffer than the 23mm tire.  The most common response we get to this graph is, ‘That’s not possible, I went from 23s to 28s, and it’s noticeably better.’ 

My initial thoughts about this were that the ‘Just Noticeable Difference’ which is the smallest change that can be accurately noticed by humans has been shown to be between 10 and 15% for ride stiffness (much of the work on this was done by Damon Rinard, mentioned in Part 1 and his work on this topic with Cervelo can be found HERE)..and the difference here between the 23 and 28mm tire is only about 8-9%.  

I have often seen in testing that if a rider believes something to be true, he/she will very often ‘feel’ that in the test ride, particularly if the effect in question is relatively small.  So based on this first piece of data, it would seem that perception and expectations may be driving some of the ‘wider is more comfortable’ beliefs (assuming the same tire pressures). However, there is clearly much more to learn.

So with this data in hand, we went about building a complete data sheet of all 3 tires at all 3 pressures on the 17.5mm Rim.  We used 6Bar, 7Bar, and 8Bar (87 psi, 101 psi, and 115 psi) to build this data set as it gave us a large total range of pressures commonly run in tires of these sizes.

23, 25, 28mm Tires on Same 17.5mm Bead Width Rim at 3 Pressures – Flat Surface

This graph really helps set the stage for the relative differences we are looking at.  As the tire pressures were changed in 1Bar increments (14.5psi) you can get a feel for the magnitudes of difference between the width changes, in this case increasing from a 23mm to a 28mm tire at 7Bar increased stiffness by 9%, while increasing pressure by 1Bar increased stiffness more than 21%.  The data grouping is mostly dominated by tire pressure, so clearly, the effects of these 2-3mm width changes are below the 1Bar delta in pressure change used for the test.

To really take this study to the next level, we decided to not just push on the tires with the flat surface but to also look at a simulated cobble-stone (8cm radius) and a simulated pavement lip (8mm radius) to see what the effective stiffness of the tire would be against those surfaces.

Visualization of 3 Different Test Anvils Used for Testing

'Cobble' Surface (8cm Radius) Data

Here is the data for the same 3 tires on the 17.5mm Bead Width rim at the same 3 pressures; only the ‘anvil’ in the test machine is now a machined piece of steel with an 8cm radius to mimic the crown of a cobble.  

23, 25, 28mm Tires on Same 17mm Bead Width Rim at 3 Pressures – Cobble Surface

Of note is that the rounded impact anvil, ‘the cobble’, resulted in a considerably lower force at the 15mm displacement than the flat surface.  This is largely the result of how much of the tire is able to deform at the contact patch between the anvil and tire. 

Interestingly, with the Cobble Impact head, the radial stiffness is still mostly dominated by tire pressure, though the differences between the tire widths and pressures have condensed somewhat.  The shape of the object being pushed into the tire makes a large difference in the tire's stiffness.  With this data set, we are beginning to see some overlaps; for instance, the 23mm tire at 8Bar is very nearly identical in stiffness to the 28mm tire at 7Bar.

'Pavement Lip' (8mm Radius) Data

Wanting to push this further, we looked at the same conditions with an 8mm radius anvil, which simulates a concrete lip, rock, or similar object that your tire may hit.  As the radius of this anvil is considerably smaller than any of the tires, we were interested in seeing how the data would change. And, wow, did it change!

23, 25, 28mm Tires on Same 17.5mm Bead Width Rim at 3 Pressures – 8mm Radius

Look closely, and you will see that the results have completely separated out by air pressure and the different width tires have become almost identical to each other when at the same pressure.  It would appear that for this small radius, the tire size is of little factor compared to air pressure.

So what has happened to drive this?  It would seem that the changes in air pressure are making similar differences to previous studies, yet the tire width is not contributing in quite the same way.  There is more to learn here for sure, but at this point, it seems that for bumps smaller than the tire diameter, the shape and size of the bump are driving the stiffness more than the effective width of the tire itself.

Please see the post-script to this paper about why we believe this to be true, but keeping it simple based on the data we’ve seen here, it certainly seems that wider tires are every bit as good or better at absorbing small bumps and imperfections than narrower tires at the same pressure.  This is most certainly not the expected outcome of the study as we planned it when we started, but most certainly is a fascinating one!!

Converting it to Vertical Stiffness

Up to this point, we have been using the phrase 'Stiffness' to explain these graphs, which are actually Force-Displacement Graphs.  Stiffness is actually defined by the slope of the line in the graph, but adding that made the graphs even messier and harder to read!  Below are the actual calculated stiffness values from these tests.  These values will become important in part 3, where we look at how the tire stiffness affects the ride quality of the entire bicycle system.

Vertical Stiffness of 3 Tires and 3 Pressures against 3 Surface Geometries

Summary and Recommendations

What we can say is that all those people who feel their larger tires are more comfortable, you may be correct for bumps smaller than 8mm radius...we could not measure that, so it is hard to know, but for larger radii, you are best to lower your air pressure a bit to truly take advantage of the larger tire widths.

The most exciting aspect of this study is that it has begun to point us in the direction of how much pressure we need to lose with tire width increases, and even better, it hints that while lower pressure will provide similar ride comfort on most surfaces, it will likely improve comfort on small bumps.  

Our recommendation is that you decrease tire pressure by 2-3% for each millimeter of tire width increase. This will ensure similar compliance over most surfaces while providing improved compliance over small bumps and edges.  Keeping a log of your pressure experiments will help you decide what pressures are ultimately most comfortable and most efficient for your weight and road surfaces.  This will be important to know as we begin discussing Rolling Resistance and Aerodynamics.

Our next Tech Tuesday discussion will cover Ride Comfort and Compliance and how tire pressure and stiffness affect the entire bicycle system.

Post-Script

I have to say that at this point, we certainly don’t have the answers to the questions brought about by this data, but we consider it a reasonable theory that there is something happening at the interface between the small anvil and the tire, which is adding apparent stiffness to the smaller width tire data.  This could be the result of casing stiffness, localized distortion, surface friction, or other factors.  There is more work to be done on this.

Also, for the purpose of this study, we are only showing the force at 0 and 15mm of displacement.  This is partly to keep the data clean but also to simplify the chart reading.  We found for each test that the first few millimeters of displacement were non-linear, and then the graphs would become more or less linear.  For the sake of keeping our sanity working with the data, we chose to assume that the curves are fully linear.  However, with the 8mm anvil, the data showed a larger non-linear section, so this is likely due to the relatively extreme localized deflections and deformations required within the tire at these large displacements.  

15mm was chosen as the deflection data point to ensure that none of the tires were beginning to bottom out on the rim.  Past 15mm, the force data for the 23mm tires begins to bend upward as the casing deflections become extreme, and then inner-tube materials become pinched within the system.  Taking stiffness data from 0-15mm deflection ensured that the force data represented the effect of the casing stiffness and the air spring only.

Common Tubeless Tire Issues Solved

We sincerely hope that your tubeless installation goes smoothly and holds well, but unfortunately, this is not always the case. Every tire, rim, and tape is different and can cause some of the following common issues. 

Some common issues that we have seen include:

- Sidewall Weeping 

- Sticky Valve Cores

- Air Leaking from the Valve or Nipples

- Kinks in the Tubeless Bead

In the case that you are unfortunately not having the smoothest process and experiencing one of the above issues, please reference this informational blog post.

If you would like to cancel or edit your order, please contact our customer service team at sales@silca.cc or by calling 1-800-905-2157. Please include your order number and the reason for cancellation or details of the change you would like to make in your message.

Orders can only be canceled or edited before they have been dispatched. If your order has already been shipped, please refer to our return policy for further instructions.

'No single adjustment to a bicycle will affect comfort, handling and confidence as much as tire pressure.' 

 

 

Make that 'Harsh' Aero Bike Ride like 'Plush' Comfort Bike: Change your pressure!

That's a bold statement, but one that has proven true over and over again.  One that has driven professional athletes and mechanics to use high-tech pressure measuring equipment, high-accuracy gauges on pumps, and even tire pressure spreadsheets and logs covering course and conditions as well as tire choice and pressures.  For this part in the series, we will look at the 'Why' behind the bold statement.

First of all, every component of a bicycle is essentially a spring.  Even things that seem very rigid will deflect at some load.  That seat post seems quite rigid, but load it, and it will bend slightly.  Engineers take the amount of load applied and divide it by the amount of deflection to get the 'spring rate' of the item in question.  This is what we did with tires in Part 2: we loaded them up, divided by deflection, and the result was the chart below:

 

 

Vertical stiffness model for Surfaces: Stiffness given in N/mm

Technical Note about N/mm:  1 Newton (1N) is

 

The basic argument for tire pressure being the most important adjustment is that the tire is the softest spring in the entire bicycle system, and when springs are added together in a system like this (what engineers call springs in series), the softest spring dominates.  Springs in a Series add up like this:

 

 

Let's look at an example here using simple numbers, You can see that the lowest spring rate completely dominates the system:

 

 

The result here feels counterintuitive; the sum total of the springs is LESS than that of the weakest spring, so I like to think of it this way.  If we had our 10N/mm spring in series with a spring of infinite stiffness, we would be left with a spring rate of 10N/mm, since any other spring we put in series with the 10N/mm spring has a rate far below infinity, then the system will be less stiff.

When we talk about comfort in terms of cycling, the system from the ground up is made of springs in this order: tire, rim, nipples, spokes, hubshell, bearings, axle, frame, seat post, and saddle.  For simplicity, we generally measure wheels as built and the frames as frame and seatpost.  We also have an amazing resource in Tour Magazin in Germany, which measures frames for vertical stiffness from the seat post-rails to the dropouts.  This gives us a single 'frame-seatspost' stiffness number to work with.  So, for our purposes, we will use this equation where K is the spring rate variable:

 

To the engineer, all of this looks something like this (and yes, I know that the 'rear' wheel has radial spokes, it's just for visualization! ;-)

 

 

CAD Visualization of Springs in Series Model of Bicycle/Wheel/Tire System 

This helps visualize the differences in spring rates where a wheel can be 5-10 times stiffer than the frame/seatpost, which will be 2-5 times stiffer than the inflated tire.  In all non-suspension bicycle systems, the tires will be the spring dominating the system over bumps and other rough surface features.  

Putting all of it together: Effect of Different Frames

To put all of this together, we've created a small chart based on our tire data, the wheel stiffness data from the Road to Roubaix Story, and some frame stiffness data based on actual data taken from Tour Magazin out of Germany.  The Tour stiffness data measure from the seat rails to the rear dropouts, so it gives us an excellent model for the ride stiffness of a bicycle as it would be sold to you.

We modeled using 3 different frame stiffness: 250N/mm, 200N/mm, and 150N/mm.  These are generally representative of what we see in the Tour Magazin data for frame vertical stiffness, though there are outliers worth noting.  We highly recommend looking at Tour Magazin data as there is a very aero bike with 125N/mm stiffness and another 'Comfort' looking model at over 300N/mm stiffness, which goes to show that the design details of a specific frame can certainly matter more than the look of the frame!

For the sake of this study, we have broken all of the tested frames into 3 representative ranges, which fall in the Stiffest Third, Middle Third, and Softest Third of the complete data. We called these ranges 'AeroRace', 'Race', and 'Comfort' to simplify things.    The actual data from the last few years spans 100N/mm-350N/mm for road frames.

The chart below uses our spring equation with actual measured data from our tire study, wheel study, and frame/seatpost study, The resulting data represents the system stiffness from seat post rails to ground.

 

 

 Vertical stiffness model for 3 Frame Categories: Stiffness given in N/mm

For these models, we are looking at the system stiffness on an 8mm bump with Zipp 303 wheels, 3 different tire sizes, and bicycles from the 3 general classes we defined above.  What is notable about this is how much the system stiffness is dominated by tire pressure; in fact the difference between the 'Aero Race' frame/seatpost and the 'Comfort' frame/seatpost is LESS THAN 1 bar (14.5psi) of pressure!  

Clearly the differences between the stiffest third of bikes tested and the most comfortable third of bikes tested are very real, but it just isn't very large in magnitude when you consider that you can go up a tire size and down 1 bar of pressure and be roughly equivalent or even better off.  Again, when optimizing for a specific event or race, the athlete should be maximizing every single advantage within the system for the largest possible total benefit, however, if you only can afford one very expensive race bike, you can take comfort in knowing that some clever air pressure strategy can put you right there with your comfort/endurance bike friends in terms of ride quality.    

Now, let's look at the differences within a category.  Below are the equations run on 3 different bicycles within the 'Comfort Race' category.  All of these bikes have been ridden at Flanders, and all of them are top sellers from major brands.  

 

 

Comparison of 3 Comfort/Endurance Race Bike Brands with the Same Tires and Pressures

These three models are all highly successful and all hotly sold against one another in the market touting the industry standard mantra 'laterally stiff yet vertically compliant.' 

While there are differences between them, it equates to about 0.2Bar or 3psi difference in tire pressure.  While this difference is non-zero, it is also less than 1/3 the gauge error and within the range of repeatability of most bicycle pumps.  Think about that, between these 3 $10,000 models, the difference in ride quality is equal to the difference you will get if you pumped to the 'same pressure' each day and is likely a fraction of what you would get if you pumped to the 'same pressure' on somebody else's pump.

Editors Note: This was the 'smack in the face' moment for me during the Roubaix project, the realization that the quantitative difference between the bike the team was convinced was 'too stiff' for Roubaix and the bike that was completely designed and optimized for the race, was less than 1bar of air pressure.  Clearly, you take every advantage you can get, and every little bit helps, so you take the most comfortable frame, the most comfortable wheel, AND you optimize the pressure.  Yet, at the same time, we so often paint these decisions as being black and white, and they simply are not.  The reality is that the difference between the 'too stiff' bike and the 'just right' bike on a normal day is about the difference you get if you haven't pumped your tires in a few days.

Putting it all together: The effect of wheels

The effect of wheels and comfort has been long debated, and I count myself as being completely surprised to learn that my own 'magic carpet' Ambrosio Chrono Roubaix wheels weren't actually that compliant.  These effects again point to the strong placebo effects of believing something to be true and also point to the 'Just noticeable difference' threshold as being greater than most of the variables we are changing here.  Look at the chart above again, and you see that the difference in system stiffness between the 250N/mm and 150N/mm frames with 28mm tires at 8 Bar is right at 10%, which is right on the edge of what people can perceive when blinded to the study variables.

Of the 3 springs in our model, the wheel is by far the stiffest and therefore has the least effect.  As to our point above, they still make a difference in the model, so optimizing wheel stiffness is worthwhile, but as you see below, the effects are significantly smaller than those of the frame and roughly 1/10th of the effects of tire pressure:

 

 

Vertical stiffness model for 3 Wheel Models: Stiffness given in N/mm

Here we have the best possible example of the effects of our Springs in a Series model.  The 303 project detailed in the Road to Roubaix story was able to reduce the radial stiffness of the preferred cobble wheel by nearly 50%. It was a major breakthrough in both concept and execution, and yet, from the system perspective, it represents an improvement of just under 2%.  

What is 2%? Well, if you are a pro at Paris-Roubaix, it could be everything!  For the average cyclist reading this post, 2% is something very real that you could completely wipe out by over-inflating your tires by a few PSI.  

Conclusions and homework

Bringing all of this back to the opening statement and image, we see that the difference in vertical stiffness of the 5 frames in the opening image can be offset by using the 5 different air pressures shown on the gauge.  More interestingly, from a SILCA standpoint, is that the difference between 4 of the 5 frames is less than the gauge error of a standard bicycle pump (+/-5%), which has driven us to produce pumps with gauges of significantly higher accuracy.  It is our sincerest hope that you, the cyclist, can use this knowledge to begin doing your own testing and study on air pressure for your bike/wheel/tire system.  

When researching new equipment choices, remember, it ALL matters.  That more comfortable frame really can be a big deal.  Those more comfortable wheels most definitely are a big deal, and of course, top it all off with optimized tire pressure, because the wrong tire pressure can quite literally undo all of the benefits of the highly engineered equipment you are purchasing or already own.

Our recommendation is to begin keeping a log of your air pressures.  Start where you are today and reduce the pressure by 5 psi or 0.5Bar and ride it for a few days, then reduce it a bit more, etc.  We have worked with hundreds of athletes, both professional and amateur, and find that just a few weeks of keeping a pressure log will begin to completely change the way you think about your pressures and tires.  In many cases, we find athletes deciding that they can race their aero road bike on that course they were planning to buy a more comfortable bike for.  Triathletes, some of whom are now racing at pressures 2Bar (30psi) lower than before, are telling us that they are running better off the bike as they are less fatigued from vibration, and better still, they aren't riding any slower!  

Next week in Part 4 we will be looking at tire size and pressure and how they affect Rolling Resistance!  The results will surprise you and will explain how you can lower pressures up to 2 Bar and STILL have Low Rolling Resistance, if not even LOWER Rolling Resistance!

Using CO2 with Tubeless Setup 

It's okay to use CO2 in a pinch, but it isn't ideal. This is because CO2 is acidic, and when it hits the sealant, it will drop the pH of the liquid. Once the pH drops from 11-12 to around 9 with the use of CO2, it hardens/dries out. If you are using it just to get you home after a puncture, it's not a big deal, you'll ideally want to change out your sealant as soon as possible after this. If changing your sealant isn't an option for you, then you will at least want to empty the air from your tire and then fill it back up a few times to try to get as much CO2 out as possible and then add some replenisher to try to bring the acidity back up. 

Which bike computers will fit on a Chisela?

Great question! Our Chisela mounts will fit all Garmin computers and all Wahoo computers except the V1.This includes the new Garmin 1050! The T-Tray mounting system also makes for a removable mount for your lights, cameras, and more! 

How do I determine which Chisela will fit my stem? 

What will happen if my products freeze?

This is a great and common question. All of our products, except for the Super Secret Chain Lube, will be okay if they freeze. The chain stripper will sometimes appear more cloudy than clear, but it is just fine and will not affect the quality of the products. 

For help with the super secret, please see this article: Help With Frozen Super Secret

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Please keep in mind that order processing can take up to one business day, and we only ship Monday - Friday.

We've decided to push Part 4 back a week and do an FAQ about the first 3 segments of our series as we have had so many questions and comments regarding the series so far.  For a quick recap:

Part 1: History of tires getting wider and the effect of rim width on actual tire width

Part 2: Measuring Tire Stiffness in the Lab

Part 3: How Tire Stiffness effects ride comfort for the entire bicycle

FAQ:

Q: I weigh 210 lbs and have a history of pinch flatting.  I like what you are saying about lower pressures having more comfort, but I am worried about flats.

A1: What rims and tires are you riding on what frame? 

Q1: Mavic Cosmic, 23mm Continental GP4000s on Cervelo R3

A2: At your weight, you really need to consider wider tires.  Your frame will accommodate 25mm tires on 17c rims.  Looking at the chart in Part 1, your 23mm Conti's on those 15mm rims measure 22.2mm tall and 23.8mm wide.  Moving to 25mm tires on the same wheel will net you 24.2mm height and 26.2mm width.  The extra 2mm height and 2.4mm width will significantly increase the amount of energy required to bottom out the tire onto the rim and cause a pinch flat.

This graph shows a 23mm tire at 8Bar vs 25mm at 7Bar, Vs 28mm at 6Bar, Tires Are Displaced until Bottoming on the Rim. The area under each curve is Energy Required to Bottom Out.

The graph above shows the Force-Displacement curves for all 3 tire widths tested with the tires pushed to the point of beginning to bottom out.  The energy required to bottom out the tire can be approximated by calculating the area under each curve.  In this case, we have lowered the pressure by 1 Bar with each width decrease.  You can see that while the 28mm tire at 6Bar is less stiff (the steeper the slope of the line, the stiffer the tire) than the 23mm at 8Bar, but it can handle an additional 5.2mm of displacement which also results in a higher force at the point where it bottoms out on the rim.  In this case, the 28mm tire at 6Bar requires over 50% more energy to bottom out against the rim compared to the 23mm at 8Bar.  For you particularly, the 25mm tire at 7 bar will require 19% more energy to bottom out AND be 5% more comfortable.  If you optimize your tire pressure for equivalent stiffness (25mm at 8 psi lower than the 23mm tire rather than 1 bar (14.5 psi)), a pinch flat would require some 24% higher energy- your choice.  We like the 25mm at 7Bar for achieving the best of both worlds: more comfortable AND a significantly reduced likelihood of pinching.

Q: Since wider rims make narrow tires both wider and taller, do you treat them as if they are the same as a tire of the wider width on a narrower rim?  For example, a 23mm tire on a 19c rim should be the same pressure as a 25mm tire on a 17c rim, as they are similar on your chart.

A:  While a wider rim may make a 'narrower' tire measure wide, it doesn't necessarily make it as tall, and it is the height of the tire that gives you the protection from pinch flatting.  Generally, we suggest that lighter riders, or riders on smoother pavements, can consider narrow tires on wide rims to be similar to wider tires when setting pressures.  However, on harsher pavements, gravel, cobbles, etc, there is NO SUBSTITUTE for the added height of the tire with wider casing, and if possible, you should choose the wider tire AND the wider rim.  

Look at the actual size chart again:

Note that the 23c Tire on 19.5mm rim is almost exactly as WIDE as the 25c Tire on the 17C rim..However, from a pinch flat/rim damage perspective on rough pavement, cobbles, gravel, etc, the 1mm height difference between them represents a significant difference in the energy required to bottom the tire against the rim.  So we must look at both from a perspective of balancing grip, comfort, and rolling resistance (to be covered in Part 4) AND from a damage pinch perspective.  If rim damage or pinch flatting is your issue, then the best solution is the wider tire, followed by pressure optimization.

Q: Why did you bother measuring tire stiffness? We already knew that wider tires are stiffer, and you should lower air pressure.

A: From working events around the world, I would say that the statement 'we know this' is quite an overstatement.  Over 80% of the people we talk to at events (including pro team training camps, ProTour Races, major gran fondos, the Olympics, etc) say that they run the same pressure in their wider tires or with their wider rims than they did before.  I honestly believe that much of this is just a matter of habit and the belief that it is better to have too much pressure than too little.  I see athletes and mechanics alike continuing to just throw 120 psi into front and rear tires without even considering what those tires are.  

As for measuring this effect in the lab, our study was actually one of only 2 that we know of to look at actual vertical stiffnesses of inflated tires against different forms, and the other source of data is not a published source, but rather some data shared by Damon Rinard, one of the kindest cycling engineers around.  Surprisingly, the data on this topic is very thin to nonexistent, and while you can easily find dozens of tests of frame, seat post, wheel and other stiffness testing, there is almost no actual vertical spring rate data on the tires, which is ironic as the tire completely dominates the system (as was shown in Part 3). 

Much of the inspiration for this series actually comes from taking our 'Inflation Station' to races around the country and finding that in more than half the cases, we end up removing air pressure from people's tires.  I would confidently say that in road and triathlon-type events, including Gran Fondo events, over 80% of the people are running too much air pressure.  

Q: If wider tires are stiffer and wider rims make the tires even wider, then are we doing this wrong?

A:  If you are maintaining your original air pressure as you go wide, then you certainly aren't doing it right!  The point we hope to make as we pull this data together is that a 23mm tire is rarely ever a measured 23mm.  So once we start talking about specific air pressure for a 23mm tire, we will need to be on the same page in terms of what '23mm means.  As not everybody has a digital caliper, we will try to be specific by saying things like '23mm tire on 17c rim measures 24.9mm' or something like that.  Essentially, what we are getting as is that if you were running 120psi on your 21mm tires on 13c rims (which will measure 21mm) then you need significantly less pressure in your 23mm tires on 17c rims which measure at 24.9mm as effectively you are on a 4mm wider tire and not actually on a 2mm wider tire as it might seem.

We also hope to convey that rolling resistance, aerodynamics, comfort, and grip are a direct function of measured tire width and pressure, while impact and damage resistance are more related to tire casing circumference and tire height and pressure.  With a little bit of knowledge, we can help you make decisions for your event.

Q: What about the MAX and MIN tire pressures listed on tire sidewalls?

A: We advise that you NEVER exceed a MAX or go below a MIN, as stated by the manufacturer.  Those numbers on the tire sidewalls are generally driven by internal testing done by the manufacturers and are related to safety rather than speed, comfort, or efficiency.  MAX ratings are there specifically to eliminate the possibility of a tire blowing off the rim under extreme conditions, such as very hot and prolonged braking in the mountains.   While MIN ratings are generally related to the minimum air pressure required to keep the tire mounted in the bead under heavy cornering.  If you feel that you need to go over or under these numbers, then you should seek out a new tire that specifically meets these criteria.

Q: What about rider weight? You aren't considering rider weight which is HUGE! 

A: This will be covered in Part 6.  As a general rule of thumb, you can scale recommendations for tire pressure by your weight compared to the weight used in the study by dividing your weight by the test weight times the pressure recommendation.  More in Part 6!

Q: This has all been covered already by Jan Heine and Frank Berto, and the answer is 15% tire drop. You should go read that article HERE

A:  Thanks, Mark. Yes, we have read Jan Heine and have seen the Frank Berto graph shown below: 

Graph showing 15% tire drop for given pressure and mass.  Source: Bicycle Quarterly

For starters, we've been using the pressures from this graph for a while, and on most surfaces and uses, these numbers are great starting points.  It has been our opinion that the chart typically results in an under-inflated front tire as cornering feel can become a bit vague or squirmy, and also, the chart does not specify road surface.  Much of the research we are doing is to try and better understand all of the interactions in play, including comfort, grip, rim protection, aerodynamics, and rolling resistance.  If we ultimately end up confirming the chart with all of this data, then that would be a major advance in the art as far as we are concerned.  In the meantime, we highly suggest everybody read the articles over at Bicycle Quarterly as well as Jan Heine's Blog, which is full of great stuff. 

Q: I've seen Josh post some stuff to Slowtwitch comparing various component changes to tire pressure changes; where is that?

A: Josh did post some stuff a while back comparing various component and material changes to tire pressure changes.  The most important thing to note about this, however, is that generalizations are nearly impossible to make.  We have seen carbon posts that are stiffer than aluminum posts, and some that are as much as 30% less stiff, so you cannot just say 'carbon post vs. aluminum post. '  Similarly, there are carbon aero frames that have equivalent vertical stiffness to some of the most comfortable 'endurance' frames and 'endurance' frames that are as harsh as the stiffest aero frames.  The data Josh posted to Slowtwitch is below:

• 1 1/8 Steerer vs Tapered 1 1/8-1 1 ¼ steerer (same brand carbon fork): 1.2psi 
• 24 vs 28 spokes Zipp 303: 1.8psi 
• 3x vs radial spoke lacing, Zipp 303: 2psi 
• Curved vs Straight seat stays, Carbon Frames (Model Year Change): 4psi
• Carbon Vs Steel Similar Geometry Custom Frames: 4psi  
• Comfort/Cobble Frame design vs Full Aero frame design: 19psi 
• Aluminum bar to Zipp SL: 7 psi
• Aluminum bar to Zipp SLC: 2psi
• Zipp 27.2 Seatpost to Zipp 31.6 Seatpost: 4psi
• Zero Offset Zipp seatpost to 25mm offset Zipp seatpost: 3psi
• Thomson post to Canyon VCLS SeatPost: 24psi

The important takeaway here, though, is that to compare two specific things, you really need to compare those two things.  Generalizations are sure to be wrong. However, this list does a good job of putting things in perspective.  We so often talk ourselves into the importance of 4 fewer spokes or replacing that aluminum part with a carbon one, when in reality, the difference in system stiffness that results is very, very small..in fact, most all of these are well below the gauge error of a standard floor pump.  Perhaps most interesting of all is how the very well-designed Canyon seat post can make a significantly larger difference than the two very different frame designs!

1. Blot up or scrape off the excess
2. Rinse the spot in running water to flush out as much sealant as possible.
3. Treat the spot with equal parts dishwashing liquid and warm water.
4. Pre-treat the spot with commercial stain remover, and then wash the garment as you would normally.

Chisela Troubleshooting 

Unfortunately, bike computers suddenly not being stable in our Chiselas is an issue that we have seen from time to time. This is often caused by a small tab being damaged on your Garmin or Wahoo puck. Please use care when mounting, removing, and moving your computer, as excessive force during these processes can damage or break this small tab. If you believe that this broken tab may be the cause of your issue, please refer to the information below or reach out to us.

What "tab" are you talking about?

Please see the pictures below of both the Garmin and Wahoo mounts. The "tab" that has been referenced can be seen in the bottom left or right of the puck. If you do not see this tab on your puck, it has most likely been broken off, and a new puck is needed. 

How can I get a new puck if mine has been broken?

New pucks can be ordered here: Replacement Pucks

Please make sure that you select the correct puck for your computer brand. 

Part 4A in this Series covers the history of Bicycle Rolling resistance and the how and why Pneumatic tires are so awesome.  If you just want to see the data, you can jump to Part B HERE

Back in 2007-2008, during the Paris-Roubaix wheel development, I had an interesting moment in the Arenberg Forest.  I was working with one of the most famous Roubaix winners of the last 10 years, one whom I had also worked with to win Tour Stages, Tour time trials, and even a World Championship.  We had been running tires at ever lower pressures, trying to find the point at which a rim/wheel failure was inevitable, and right there plotted out on the screen was a trend that has been frozen in my brain for these last years:  every time we lowered pressure, he went faster.

It has long been known in CX and Mountain Bike racing that lower pressures are faster, but in road racing and triathlon, we have long held onto the belief that most road and even cobble surfaces are smooth enough that higher pressures will be faster, at the expense of comfort.  Even at the beginning of my history with Paris Roubaix testing (~2005), the belief was that we needed to find pressures high enough to be fast yet low enough that the riders could handle the bikes over cobbled sections.  And yet, right there, every which way we looked at it on the computer, repeated across multiple riders: Lower Pressure was Faster.

Fast forward to today, and we have numerous good sources for Crr (Coefficient of Rolling Resistance) testing, and we have a real movement to identify and improve aspects of high-performance tires.  We are, in many ways, in a golden age of tire Rolling Resistance advancement, much in the way the 2000s were the age of massive aerodynamic advancement.  However, none of the Crr studies in the lab have yet truly explained or predicted the phenomenon we saw in the Arenberg Forest. 

A Theory in the Making

In the last 10 years, two sources that I know of have identified similar effects in their data. Jan Heine of Bicycle Quarterly has written about the effect he calls 'Suspension Losses', which you can read HERE.  Some of Jan's most interesting work is in looking at the power required to ride on different surfaces, including very aggressive ones such as highway rumble strips.  

The theory behind 'Suspension Losses' is rooted in pre-pneumatic tire experience and is also a topic of discussion amongst in-line skating athletes.  Solid tires make surface roughness incredibly apparent to the athlete both in terms of comfort AND speed. 

Imagine a rigid tire and wheel rolling over a 5mm bump in the road.  In this case, the tire is rigid, so the entire wheel/tire and, therefore bicycle will be raised and lowered by 5mm

Model of a Rigid Tire on 5mm Bump. This scenario is quite literally how the early 'Boneshaker' bicycles earned their names, it was neither fast nor comfortable.

The rider of the bicycle becomes the suspension system to absorb the bump as the tire is incapable of handling it at the point of impact.  The forward momentum of the bike is converted into a vertical force, which is partially absorbed within the rider's body as well as absorbed in friction at the contact points between the bike and rider.  

Another way of describing it is that the bump is essentially lifting the entire system by 5mm and dropping it in a sort of pavement bench-press of the bike and rider.  Think of 1000 5mm bumps in the road as the road doing 1000 mini-bench presses of a 180lb object, and it becomes clear that energy is not being used wisely in this scenario.

Pneumatic tires were such a revolution as they were not only more comfortable but proved significantly faster than the solid tires they replaced.  

Looking at the similar bump with a tire modeled at 100 psi and we see that rather than lifting the system by 5mm, the system is only lifted 1mm off of the ground, with the other 4mm of displacement being absorbed by the tire.  As the pneumatic tire is very efficient, much of the energy absorbed is returned, with the primary losses being small amounts of heat produced in the tire casing.

Model of 23mm Tire at 100psi Absorbing 5mm Bump.  The entire system is lifted 1mm, with the rest absorbed by the tire. 

Our second data point came from Tom Anhalt, who has been studying Rolling Resistance and other bicycle physics on his website HERE

Tom has picked up the baton from Al Morrison and has been measuring and posting bicycle tire rolling resistance data taken on rollers.  Tom posted a very interesting piece in 2009 related to the differences between roller testing and real-world testing, where he was able to roughly match roller data at lower pressures but saw a divergence in the data at higher pressures.  Tom's article mentioning this was published at Slowtwitch.com and can be found HERE

Similar to Jan Heine's data, Tom found that rolling resistance decreased as pressure increased up to a point and then began increasing again as shown below:

Tom Anhalt's Real World Tire Test on 'Good' Asphalt Surface, Compared to Identical Tire Tested on Rollers by Al Morrison

Tom coined the phrase 'Break-Point Pressure' to describe the point at which the Crr changed from decreasing with pressure to increasing with pressure.  Tom was also the first to theorize that we could estimate what he called 'Transmitted Losses,' which were the losses due to vibration and roughness, and that we could (and should) model them into our theories about optimal tire pressure.  

A new term: Rolling Impedance or just Impedance

For the rest of this series, we will be using the term Impedance to define this resistance to forward motion caused by surface roughness.  I have stolen the term impedance from electrical engineering, where it is defined as the resistance of a circuit to an alternating current.  The phrase feels more natural to me than any used previously and was also approved by Tom Anhalt, so we hope it sticks.

Part 4B will take the concept of Impedance to the next level and help us begin to understand how to compensate with our tire pressures.

Preventing a Clogged Valve Stem when using Sealant 

The best way to prevent this from happening is to store your wheels so that the valve stem is at the 6 o'clock position. This will allow any sealant to drain out of the valve stem. Then, when it's time to pump up your tire, turn the valve so that it's at the 12 o'clock position. This will allow any sealant that's pooled underneath the valve to drain away from the area so that it doesn't blow back up into the valve when you're pumping air into the tire. It is always a good idea to have some spare valve cores around when you're using sealant, though, as, unfortunately, clogging can happen. When installing a new valve core, it can also be helpful to add a lubricant, like our Synergetic, in and around it to help prevent any sealtant from settling in the stem. 

The color changed

ROLLING RESISTANCE (CRR) AND CASING LOSSES

 

IMPEDANCE

 

 

 

THE TEST

 

 

 

TIRE PRESSURE LESSONS LEARNED

 

LESSONS LEARNED

 

 

'23mm' Tire Measuring 24.89mm Wide at 6Bar (87psi)

Part 1: How We Got to Now

No other single component affects the comfort, handling, and efficiency of a bicycle like the tires.  Tires are the sole connection to the ground; they are the sole transmitter of drive force to propel the cyclist forward, and they are the sole means of gripping the road during cornering.  They are the most dominant spring in the bike/rider system, which means that more than anything else, they control comfort.  They are the sole component that will (ideally) ever have to resist the abrasive contact of asphalt, concrete, or gravel with minimal damage.

In future segments, we will show data discussing the Aerodynamic, Comfort, and Rolling Efficiency of tires, but for starters, we will be looking at something seemingly so simple, yet not simple at all.  Tire Width.

Years ago, tire width was quite a simple affair.  Tubular tires were sold in different casing widths, which they maintained even if not mounted to a rim.  A 21mm tire would measure with calipers at 21mm +/-0.5mm.  With clincher tires, this became more complicated as the interface between the tire and rim became a factor in the tire size discussion.  Manufacturers were led by the ETRTO to recommend which tire sizes worked with which rims, and the conventional wisdom of narrower tires being faster kept everybody in check for some 30 years as racing rims measured 13mm between beads, road rims measured 15mm between beads, touring rims were 17mm, mountain rims were 19mm, etc.  

Fast forward to now, and things are much more complicated.  ENVE just released their 7.8 TT/Tri wheel set with 19.5mm inner bead width.  That's 2mm wider than the Zipp 303 we developed for the cobbles of Paris-Roubaix 7 years ago and 6.5mm wider at the bead than the original 808 TT wheel I designed in 2004.  

Many of these changes have come in a stepwise motion over the last 10 years with first the availability of slightly wider racing tires (23mm as opposed to the previous 21mm standard), which led aero wheel companies to make wider wheels to try and offset the aero penalties of the wider tires.  Then, athletes took advantage of the wider wheels and began trying (and liking) even wider tires.  This has gone on in 1 and 2 mm increments for some years now, resulting in the world we live in today, where the fastest racing tires are being launched with the smallest sizes at 24 or 25mm width!

As this was happening in the Road, gravel was gaining popularity as were fat bikes.  In many ways, gravel riding has further pushed road wheel development toward wider format rims, while fat bikes have pushed Mountain to think wider as well.  Today, we even have plus-sized mountain tires that are significantly wider than anything we would have imagined riding 20 years ago.

For this first part of our study, we have focused on road wheels and tires, but the learnings here are applicable everywhere.  The main lesson we want to convey is that tire size is no longer accurately linked to the number on the sidewall but rather needs to be measured based on the rim you are mounting it on.  These measurements will give us a foundation for future discussions of aerodynamics, Coefficient of Rolling Resistance (Crr), and other topics. 

Many road tires are still given their widths based on the old ETRTO fitment standards, so that 23-28mm tires are still often based on fitment to 13mm inner bead width rims, something you are likely only to find at swap meets anymore, and mounting these to wider rims will net you an effectively wider tire.  

This chart was inspired by my good friend Damon Rinard, former development engineer for Cervelo and now Engineering Manager at CSG (Cannondale).  I've borrowed (stolen) his format outright and populated it with data collected using Zipp, ENVE, and Continental components.

This chart is important because it shows that the same tire can be a lot of things depending on what rim it is mounted on, none of which are equal to the number on the sidewall!  We didn't measure on a 13c rim, but I can imagine that the 23 would be more of a 23mm width on the 13c rim, as would be the 25 and 28, but on a 15, 17.5, or 19.5mm rim, they are all much wider.  

Also, note how dramatically the tire pressure affects both the width and height of the tire.  This will be a big deal when we start to talk about aerodynamics later on.  The width also plays a large factor in determining the optimal pressure for the tire, which we will discuss in the next post in this series.

Simply saying '110 psi is optimal for 23mm tires' suddenly has little meaning anymore.  Which 23?  On what rim? What does it measure?  Not easy!

In our next post, we will be looking at the vertical compliance of these tires on these rims and, ultimately, the rolling resistance and aero performance, which gets even more interesting as the tires all change size with air pressure!

In the meantime, take a look at what size tire you're riding on and what size rim and see if it matches the number on the casing.  You might be surprised!

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