Road to Roubaix

Note: Before buying SILCA I was fortunate to spend nearly 15 years as the Technical director at Zipp.  I worked with the most amazing team of engineers and production specialists to create some amazing products.  This story would not be possible without the efforts and brilliance (and blood, sweat and tears..literally) of Michael Hall, David Morse, John Fearncombe, Nic James and many others.  Please check out the video produced on this by Zipp and other info from them over HERE
Thanks Everybody! - Josh


Part 1:

One might think that the catastrophic failure of a carbon wheel is a particularly dramatic, loud, or impressive occurrence, but you would generally be wrong. In an ironic twist, you find that impacts at 90% of the energy required to create a failure, can sound like a gunshot, can wrench your handlebars from your hands, or nearly throw you from your bike. However, an impact at 110% of the energy required to break a wheel can feel quite minor, and the failure itself often sounds like a sudden crunching of paper rather than anything very dramatic. Like that, your wheel is destroyed, in a whimper rather than a bang.

So went the early days carbon wheel development for Paris-Roubaix.   It was 2006 and I was convinced that aerodynamic, carbon wheels could change the face of racing at Roubaix, yet we first had to build product that was capable of surviving the famed cobbles, and even more difficult, we had to convince the riders to actually use it!

Looking back, I see that this was the start of my obsession with tire pressures, quality tools, and optimizing the minutia of cycling details. I had spent the previous 7 years developing products for aerodynamic benefits and it had been a long and difficult road convincing top level athletes to use it in good conditions.   A project to finish carbon wheels at Roubaix felt like an entirely new adventure involving different skills and new learnings.

We began the Roubaix project in 2007 with two teams on tap for 2008, Slipstream and CSC, between them we had access to Magnus Backstedt, Fabian Cancellara, Nicki Sorensen, Roger Hammond and a crop of young and enthusiastic pros looking to find their way in the world. Pro cycling at that point (and still today) was held in tension between old-world beliefs and new world science, often the tension resulted in catastrophic combinations of both worlds.

Our focus was to get the more aerodynamic carbon wheels under these riders. We had done some testing with Cancellara in early 2008 at the San Diego low speed wind tunnel showing that 58mm deep carbon wheels would be some 28-34 watts more efficient (at 30mph) than the 32 spoke aluminum wheels they traditionally rode at Roubaix, so there was some interest by the teams and riders, but still far too much skepticism to make it a near term reality.


Cancellara and Josh Wind Tunnel


Poertner with Zipp R&D Director Michael Hall, Riis and Cancellara at the wind tunnel in 2007

Like the athletes, we believed that the real hurdle to bringing carbon wheels to Roubaix was going to be comfort. The entire world believed that there would be no way to achieve the ‘comfort’ or ‘compliance’ of box section wheels in deeper wheels. After-all, we all KNEW that deeper wheels were stiffer, and therefore harsher, it had been written a thousand times and was therefore true. So in late 2007 we set out to understand the baseline standards for both durability and comfort in these ‘classics’ wheels.

An Instron machine, is generally the cornerstone of any good mechanical testing lab. Instron is the company most widely known for making this type of machine which looks like a large H sitting on a steel table. The machine works by driving a crossbar up or down at a very controlled rate, in the center of the cross-bar is a load cell and a gripper, or a pusher (anvil) which either stretch or crush the object being tested. An Instron can be used to test the strength and stiffness of most anything provided you have clever engineers to build the fixturing.




Setting up for radial stiffness test of a wheel with tire.

The initial testing was conducted with about a dozen wheels including prototype Roubaix wheels, vintage Mavic Roubaix aluminum box section wheels, and the 2007 race favorite 32 spoke Ambrosio Crono box section rimmed wheels. After the first full day of testing, crafting new anvil geometries, re-thinking the fixtures, re-thinking everything we could be doing wrong, we realized that we weren’t doing anything wrong at at all: The box section wheels were in fact, radially stiffer than most of the deeper carbon wheels!

Now this wasn’t universal, deep rims with V shapes were very stiff, though even then the correlation to stiffness was more stronger to spoke count than to rim depth, with only the original 16 spoke Campagnolo Shamal being the outlier, though with a perfectly V shaped rim, and bladed 14 gauge (non-butted) spokes, this made some sense.

However, we found ourselves in possession of data that pointed to the fact that the conventional wisdom of an entire generation of cyclists, mechanics and even industry engineers was just generally plain wrong. In the years since, I’ve taken part in studies and even designed studies to look at these perception vs reality situations and know that perception and conventional wisdom generally win, but at the time, my 2007 brain was blown away by this information.






2007 Radial Stiffness Testing of various wheels

This information really changed the entire vision of the project for us. It was immediately clear that what we believed to be the major problem “how to make a deep carbon wheel as comfortable as a box section wheel” was not actually a problem at all, in fact, most everything we were making was already there. The real problem was going to be convincing the riders of this.

With this information in hand, the team built some 20 pair of prototypes and headed to a team camp just outside the dreaded Arenberg Forest.

For the uninitiated, the Arenberg is considered the most brutal sector of Paris-Roubaix, massively crowned stones, few decent lines, incredibly narrow, sloppy when wet, dusty when dry, and worst of all, an ever so slightly downhill run-in to the sector which narrows dramatically at the entrance. The top teams put maximum effort into getting their riders to the front, and that means 60+kph speeds as the riders hit the stones.  Oh yeah, and occasionally people have been known to steal a stone here or there as a souvenir..making for the most unbelievably dangerous hole in the ground you'll see on any racecourse anywhere in the world.





            Photo Credit: Grubers 2019

The goal with the prototypes was to build sets of various strengths and stiffnesses to see what the riders would prefer as well as to determine the strength requirements of the rims. The test plan was to have them ride various lines to see if they could break the wheels and also to try and determine the handling characteristic the riders were after. After-all, we knew that we could make the carbon wheels ‘comfortable’ enough, but could we make them last?

90 Minutes

90 Minutes was all it took for 4 riders to break 20 sets of wheels on that first trip. Hard to remember the other details, but unsurprisingly comfort didn’t really come into the equation for this test. Our team was needless to say, devastated.

Yet, the testing had revealed some very useful data, and by early spring 2008, we had 404’s measuring equal in radial stiffness to the Ambrosio Crono wheels, but at more than 2x the impact strength of before. An early test with Slipstream showed no issues in more than 40 passes through the forest when paired with 28mm Dugast tires. We were ready! Or so we thought..

I don’t remember much from the day of Paris-Roubaix 2008, but I do remember getting the phone call. “Magnus broke both of his wheels and could not rejoin, we need to talk.” Devastated.

For those of you who don’t remember this event specifically, we were thrashed in the media for attempting this. A major US magazine gave us a ‘Thumbs Down’ award for ‘putting sponsor desires above rider’s safety.’ The general lament was why we would ever even attempt this as EVERYBODY knew that it wouldn’t work and that there was little benefit possible, yet so much downside risk. In those dark moments afterward I even wondered why we had even spent so much time, energy and money on this..

At 7 AM the next morning my phone rang, it was that Magnus and I felt a tremendous sense of relief when I couldn’t detect any anger in it. Turns out he was spending the day with his wife and children at Disney Land Paris, they were having a good time, and he wasn’t blaming us (too much).  He pointed to some critical factors that may have caused problems, mainly, they had made the decision to switch to 24mm tires the night before the race as conventional wisdom held that in the dry, these narrow tires were faster. He soothed my worries by pointing out that he was more than 1 stone above his weight of last Roubaix (14 pounds..I had to look it up at the time) and that he didn’t blame us entirely thinking that the tires were a mistake since the testing was all done on 28mm. He also was the first to let me know that Martijn Maaskant a young pro with the team had finished 4th on a pair of 202’s which were not anything special we had produced for the race, he suggested we look at the dynamics of those wheels as Martijn was really happy with them!

The significance of this conversation cannot be overstated, in 24 hours we had gone from the terrible people who cost Magnus his race to learning the other side of the story that we had the first carbon wheel to ever finish in the velodrome at Roubaix, and it was nearly on the podium!

The lessons learned from those 202’s with 28mm Dugast tires would pave the path to a total rethink of team wheel, tire pressure and tire management, a rethink of rim geometry, tire/rim aerodynamics, tire/rim interface and ultimately Paris-Roubaix race strategy.


2009 was spent obsessing over tires. We found that the difference between 24 and 27mm tires was the difference between making it through the forest and walking and we theorized that 28 and 30mm tires would be even better if they would fit in the frames! We learned that 10psi could increase speed over the cobbles by nearly 1kph at a fixed power. We looked back at the original stiffness data to understand how the 82mm 808 could be so much more compliant than the shallower wheels, and then we used those lessons to completely change the face of classics wheels by making a 28mm wide 303 with massively bulging sidewalls and a tire bed optimized for 27-28mm tires with an added focus on the outer rim edges where the tire bottomed out under heavy impact. These edges could be tuned to both better spread impact loading to save the rim, but also we learned that the same impact spreading could save the tire from pinch flatting.

Yes, you heard that correctly, once we had rims strong enough to survive Arenburg, we started to have pinch flatting issues..with tubulars!

Meanwhile in the test lab, we were working on solving the impact issues both for tire pinch flatting and for rim cracking. The new rim shape was very compliant under impact compared to anything else we had seen, but the effect of tires was really pretty unbelievable in terms of protecting the rim. 


Tire Height


Tire Height Typically runs 90-105% of tire height (Clincher shown here)

At a very basic level the key to the wider tires really that they are also taller. In general a tire will be slightly less tall than wide (this can vary with tread thickness and tire design, but highly efficient tubulars are always shorter than wide when installed.  So in an unloaded condition a 25mm tubular tire will keep your rim about 24mm off of the pavement when your bike is just sitting there, but when you are sitting on the bike the tire compresses (we call this tire drop) and for a drop of 15% (common) you will have only 20mm between your rim and the pavement.  So when we introduce bumps, road seams, potholes and (gulp) cobbles to the equation, we find that those 20mm really aren't all that much!


Tire Spring Rate


Clincher Rims and Tires shown with various Drop Percentages

So really the most critical aspect of tire width is that every millimeter of tire width brings a critical millimeter (or nearly) of height from the ground.  While lower pressures needed for these rough conditions increase the tire drop bringing the rim back closer to the ground.  The balance between tire height and pressure (which affects drop) is critical in balancing efficiency, ride quality and impact durability.  Solving for the most effective tire size and pressure is hard enough for standard conditions, but when you have cobbles with sharp edges and as much as 30mm of height difference between them, the problem becomes very,very hard to solve.  

All indications after the Magnus Backstedt rim failures were that the 24mm tires (which had never been tested on the pave with our carbon wheels) were the likely cause for the rim failures, but the data now could prove it.  Those 3mm of reduced height between the rim edge and cobbles meant a more than 20% reduction in the amount of impact energy the wheel and tire could handle before damaging the rim.

Evaluating the aluminum wheels used in previous Roubaix races taught us even more.  The rims were full of nicks, dings and deformations around the perimeter.  This meant that the tires were routinely bottoming our, but the aluminum was able to stay intact even when bent, dented or dinged.  Carbon fiber doesn't have these properties.  While aluminum will generally deform 10-13% before failing, carbon fiber usually will only yield 1.5-2% before doing the same.  Engineers refer to this as 'toughness' and it is critical to the amount of energy that something can absorb before failing.

One advantage of carbon is that we could design flex into the system by allowing the sidewall of the rim to act as a leaf spring.  This decouples the outer diameter of the rim from the inner, and by shaping the rim we could allow it to essentially act similarly to a tire.  While the conventional wisdom had been that the box section rim was comfortable because it could deflect radially inward, the reality is that to deflect inward in one place, it had to deflect outward somewhere else and all those spokes kept that from happening.  With carbon, we could engineer the flex into the cross section of the rim so while the inner diameter of the rim remained more or less round, the outer diameter could flex, this is almost exactly how a tire behaves.


HighSpeed Video of 303 Prototype Impact - 3.5mm Rim Compression After Tire Bottom-Out

This video of a 303 prototype shows the ability of the very bulging rim to deform similarly to the tire, the cross-section of the rim can deflect outward allowing the rim to compress under load.


Once we had the hard data on impact energy with the various tires and had developed new rim concepts that we believed could better handle the shock loads of the bottoming tire, we had an even larger problem: Perception.  The perception was that the 24mm tires were 'Faster' in dry conditions.  Now the problem with Perception and Conventional Wisdom is that it isn't always rooted in data, but is rather the result of people drawing correlations between features and benefits.  So when we talked with the riders we heard everything you can imagine about why 24's were faster in the dry and 27's in the wet, but the most logical was that the 27's allowed for lower pressure which meant more grip in the wet.  24's were also more aerodynamic according to the riders and this seemed logical as wider tires always bring a drag penalty from everything we'd ever seen.  So the challenge really became to make the wheel as fast with the 27 as the old wheel was with the 24.

 Making it Aero

In 2008 we went back to San Diego wind tunnel to look at the Ambrosio Crono with Roubaix tires along with numerous 303 concepts based around tires that wide. In a lot of ways it was a very liberating test for us. Out of desperation, we had thrown out all of the conventional wisdom and had made about 20 plastic prototype wheels (by Steriolithography) that were really, really outside the proverbial box. One of those was shape that would become the Hyper-Toroidal 303 that we went to production with and interestingly, the craziest of the lot was a wildly pear shaped thing we dubbed a ‘Pear-oidal’ rim shape that would ultimately become the impetus for the future Firecrest geometry wheels


New Rim Shape


Rendering of 2010 27.5mm wide Hyper-Toroidal Rim vs 2007 22.5mm 303 both with 25mm Tire 

You can see here the dramatic difference between the 2007 rim and what became the 2010 rim. This would be the first Pave specific, cyclocross oriented rim anybody ever made, and it was very strange looking. 

I remember the first time we showed it to our sales/marketing team at Zipp. The response was anything but positive. ‘It’ll have to win Roubaix if you expect anybody to buy such a damn ugly wheel,’ was one of our favorite comments. I think most everybody had the same response at first, and of course with our 2015 perspective, it doesn’t look at all out of the ordinary.

 However, the wind tunnel data spoke for itself. 




Wheel/Tire Tunnel Data From 2008 Testing

In many ways this testing was transformative for our entire team, and it ultimately changed much about our vision for future wheels.  Note on the graph that the 27.5mm wide rim with 24mm tire is very nearly identical in performance to the previous generation 22.5mm wide wheel with 24mm tire, and the wider rim with the 24mm tire was a very significant improvement over the previous rim with same tire.  This test was really the one that solidified the movement al all rims to very wide widths as previous to that only the 808 was 27.5 wide as it was necessary due to the depth.

The data from this test as shown above became a critical factor in getting the riders to open their minds to using them again following the issues of 2008.  The difference between the aero wheel with a 27mm tire and the old wheel with the 24mm tire was between 15 and 30 watts depending on wind angle...that is a tremendous amount.  Now we can't think for a second that this changed anybody's mind.  Cancellara made a very good point that this only mattered to him if the other guy was on the 303, otherwise he would rather pick the more proven and robust wheel that was equal to what the other riders had, than to have a faster wheel that brought risk of a rim failure.  

Changing Perceptions

For 2009, we continued to try and convince Cancellara and CSC, but we were also working with the very technically advanced Cervelo Test Team, and with the help of CTT management were able to convince the riders to have a go on the carbon wheels, but it would require extensive testing.  However, the Backstedt failures still loomed large with many riders and others just couldn't come to terms with the 27mm tires, or the idea of carbon wheels being comfortable.  These are times where data is critical, but even in the face of very good data, perceptions can drive what the riders are feeling (or think they are feeling) and perceptions can drive doubt and doubt can be a very self-fulfilling thing.

Our first test with CSC in the Arenburg that year brought highly variable results, ones which made no real sense and left our team, the riders, and the staff feeling uneasy.  The breakthrough came when we realized that amongst the 3 pumps on the team truck, we had a variability of 12psi when inflating to 70.  This all came in a fit of frustration when we plugged two of the pumps together on a valve stem ripped our of a tube, pumping the one to 70psi had the other pump showing 64psi and plumbing it to the third gave us 76psi.    Considering that we had been working to optimize pressures for riders like Thor Hushovd down in the region of 64 front / 70 rear, it was no wonder we were having intermittent failures and other issues.

We were facing as much as 12 psi pressure difference depending on which pump was being used!

We changed to only using one pump and completed testing with much better results, but the riders were still uneasy about the whole thing.  Before the CTT test we decided to improve the level of control.  We built a gauge setup we jokingly called 'The Truth' using a $500 Ashcroft 0.1% accuracy digital gauge, an old SILCA disc adapter and some precision industrial components to create a gauge with very high accuracy bleed.  The Truth was capable of bleeding pressure at a rate which could yield repeatable 0.05psi readings.  We knew that this accuracy and precision would be key to getting repeatable data and also to making sure that we got it absolutely right on race day.


SILCA Super Pista


Photo of 'The Truth' Gauge Hanging out at the Service Course with Team SILCA Pump (2009)

Now that we were properly prepared, the CTT testing went as smoothly as you could possibly imagine and the team was sold.  We spent a lot of time trying to find a good balance of comfort and feel for the riders by lowering pressures, but also safety margin for the wheels by not going too low.  This type of iterative testing takes a lot of time, but we found through use of power meter data that as the pressures decreased, the speeds also went up.  The better the ability of the tire to absorb the impacts of the cobbles, the more efficient the bike travelled over the cobbles.  Similarly, once the rim was routinely bottoming out, the speeds come down again.  It was as if we had opened a door into an entirely new critical variable in performance and were the first to begin imagining what benefits were there to be found.

Roubaix 2009

The Flanders-Roubaix week came and went in 2009 with little drama.  Thor Hushovd finished 3rd, the first podium for a carbon wheel at Roubaix and Roger Hammond finished 4th. 




Roger Hammond on way to 4th in 2009 Roubaix (photo from

The planning and preparation had done us well, Hushovd and Hammond 3rd and 4th.  Roger also pointed out something that would be critical to all future Roubaix attempts.  He noted that the latex tubes weep air, that is they allow air to slowly escape, which is why your tubular tires need to be inflated every day.  However, this request was that he noticed the tires were lower at the end of the race than the beginning and shouldn't we look at optimizing pressure for the Arenburg and then figure out what the race starting pressure should be since the two happen about 4 hours apart?

It was immediately clear that for 2010 we would be spending a lot of time with 'The Truth' and a stopwatch..

PART 3:  We Just Invented the Future!

The podium and 4th place for Thor and Roger at the 2009 Roubaix had been a real rush for the team, we were truly thrilled, but at the same time it felt like the learning had just begun.  

First of all..

Not much about this type of engineering is very glamorous, looking back on it I realize now that all of these stories sound rather romantic, but being there at the time reminds me of that old joke about flying where the punchline is something like 'long periods of boredom interspersed with moments of shear terror.'  Much of the time spent with the teams is spent cleaning things, fixing things, replacing things, and preparing for other things.  It's non-stop work making sure that every single detail is covered, every bolt is tight, every tire is perfect and while enjoyable it generally isn't very exciting.

Riding in the team car at Roubaix is a truly bone shaking and mind numbing experience, the roads are narrow, the riders are far ahead of you and there is no way for the cars to get past each other in the Pave sections so it makes for hours spent listening intently to race radio (in French) to hear who had a flat, needs a bottle or when crashes occur.  Every single puncture or crash announcement comes with a massive adrenaline rush, 'Oh $@#$ it is OUR guy?  Is it OUR product?! Is it a wheel failure?..'  Everybody experiences the same, the mechanics are thinking 'It is something I did (or didn't do)?!?!' the environment is unbelievably stressful, and unlike most races, you have these long periods where you can't get to them quickly..

Our biggest excitement from 2009 was tiny cracks in rims as well as some pretty serious tire cuts AFTER the race.  These evoke that certain kind of fear about things that could have or might have happened, but like a scary movie you've seen before, the ultimate outcome is known already.  So 2009 was mostly boredom during the race itself, with the fear happening before and after the event.

On the technical side, all of these emotions are really a mixed bag.  The problem for the engineers is that you NEED to see failures in order to understand how and where to improve, but at the same time, you need to see them before the event an not during.. Yet, looking at the speed and power data, there is just nothing you can do in training or race prep that comes even close to the real thing, so technically, nothing you do in testing is going to come close to the real thing..

Some fun P-R race data I've seen:

1 minute power leading onto the Arenburg Pave: 658 watts

1 second wattage on the Arenburg Pave: 1584 watts

5 minute wattage covering run into Arenburg AND 2,400 meters of Pave: 561 watts

These are truly amazing numbers, and as you can imagine not something you get in training runs.  We even tried motor pacing riders onto the Pave..but nothing matches the adrenaline and quite honestly the terror of running this stretch in th actual race!

More testing

The opposite of all that race adrenaline are the hours spend measuring the rate at which tires weep air, or impact testing tires and rims at a range of different pressures and sizes.  

For 2010, test engineer John Fearncombe developed a highly automated impact test platform at Zipp which used the basic concept of the UCI test rig, but could automatically launch the impact sled at very precise speeds and energy.  This allowed the team to very quickly test the spring rates of tires at various sizes and pressures, find the ultimate failure energies and make extremely direct comparisons between options.  For instance, a carbon wheel with 28mm tire might handle a 90 Joule impact before failure while an aluminum rim may be dented at 70 Joule and rendered unrideable at 80 Joule when used with same tire.  We could also create equivalency between systems, so if a rider liked one wheel and tire at one pressure, we could test that and them iterate the new wheel or tire using pressure to have identical spring rate.  Over a few months we impacted literally thousands of combinations:


Impact Sled Testing with Steel Cobble

The end result of this was a matrix of pressures and tire sizes to render equivalent spring rate.  We will publish something similar in an upcoming technical paper on tires, but for the team's purposes this became an invaluable tool to ride tuning.


Solving for Latex Tubes

Thanks to Roger Hammond (who is not just one of the greatest english speakers and hard-men ever to ride the Pave, but is also a mechanical engineer) we would spend the run up to 2010 Roubaix evaluating the leak-down rate of the team tires while also convincing them to go ever wider!  Turns out that a tubular tire with latex tube will lose 0.5-1.5psi per hour, which over a 7+ hour period (figure the race will be ~6:30 and the mechanics have to have the bikes ready at least 30 minutes before the start).  This turned out to be a very critical aspect of pressure optimization and planning as the comes some 4 hours after initial inflation and the nearly equally bad (but the riders are strung out and going slower..) section at the Carrefour de l'Arbre comes nearly two hours after Arenburg.

We ran testing leading up to 2010 in the Carrefour de l'Arbre looking at the minimum allowable pressures for that sector and determined that those numbers would be used, plus the leak down rate to set the starting pressure.  The wheels for the top riders were selected from the tires that had the lowest lead-down rates (near the 0.5psi per hour) and the numbers were written on the sidewalls to be sure and the race morning pressures were given to the mechanics with all of this factored in!

Doubts remain

During the week long run up to Roubaix, some of the riders, Fabian chief among them still had some doubts. Remember that he had won the event previously on the old-world wheels and tires and wasn't sure that he wanted or needed the new technology.  This is understandable as the large tires and carbon wheels seemed to offer small benefits yet come with large risks.  One of the problems is that riders really don't 'feel' aerodynamics while riding..this is true for all of us, you go hard, you go fast, there is nothing really to compare to. 

To try and demonstrate the benefits in the real world (the wind tunnel doesn't always 'feel' real).  We did a test both on the cobbles and on a few pavement sections between some of the key sectors where it seemed an attack might be likely or where a rider might find himself isolated.  The results were eye opening.




Fabian's mechanic Roger Changing Wheels on the Recon Day (AFP)

With the larger tires, we found that the riders went faster over the Pave as pressure was reduced..until the point that the rim was bottoming out, and then the speeds reduced again.  

This is similar to the effect of why increasing air pressure can make you slower on rough roads, rather than the tires absorbing the imperfections in the road, the bike is being lifted or rather bounced over the bumps.  A tire bottoming on the rim dramatically increases the spring rate of the system causing the bicycle to bounce off of the cobble which can cause loss of traction, discomfort and loss of speed.

Coming out of the Pave portion of the testing the riders seemed to be truly sold on the larger tires once and for all.  The 28mm tire in the low-mid 60psi range proved to be nearly 1km/hr faster than the 24mm tire with pressure in the mid 70 psi range (which is what is required to prevent bottoming the tire) when the data was normalized for rider power output. 

Moving on to the pavement testing, we had Fabian do some interval efforts on the new wheels and the old wheels to try and demonstrate the aero differences.  The results even shocked our engineers!  The traditional wheels with 24mm tires required 24-26 additional watts to go the same speed as the aero wheels with the 28mm tires!

Finally, we had officially debunked the conventional wisdom that 24mm were 'faster'.

Change in Tactics

This new data was worked into all of the computer simulation models and in many ways the overall picture was even more promising than just looking at small sectors of the race.  

During a Paris-Roubaix, the top riders are expected to burn 6,500-7,500 calories.  The field data pointed to a 500+ calorie savings due to improved aerodynamics (remember, generally you aren't using aero to go any faster, it is buying you the same speed at a lower power). 

The analysis of the final 50km of the race pointed that the aero wheels would allow for an extended breakaway compared to the traditional wheels.  One estimate was that using Fabian's previous data a 20km solo effort could work and with the new tires and wheels a 30 or possibly 40km final effort might be possible!

Ultimately, races are not won on technology or computer screens.  It's real people suffering at the edge of what's possible, making thousands of decisions per hour with fatigued minds and bodies.  However, all of this data, technology, and testing started to swing the belief of these riders in the favor of technology.  It felt as if the conventional wisdom was turning in our favor.




Fabian's Bike Race Morning, with hand written notes to mechanics on tire sidewalls (James Huang)

I've seen over and over that riders who believe in something are more willing to commit to it, and it becomes a self-fulfilling prophecy.  When you believe the thing is more comfortable, you fatigue slower.  When you believe a tire has more grip, you will push it closer to the limit.  When you feel that something gives you an advantage that nobody else has, you feel empowered to use it.. and so on.  In many ways, all of this technological improvement led to the biggest improvement of all, which was that these athletes now had access to better equipment, but they were willing to optimize around that equipment, and were then able to come into the race knowing AND believing in what they had done.

Race Day

The beauty (not so much..) of being embedded with the team all week sweating all of the little details in the run up to Roubaix is that you get to fly home to the US on race day to be ready for work on Monday.  I headed for the airport while the team headed to the race depart, knowing that every possible thing that could be done was done.

Some nine hours later I landed in the US and turned on my phone as the plane taxied to the jetway.  Nothing..and then suddenly, text after text and message after message of congratulations..  Fabian had ridden an unbelievable race.  Funny enough, he attacked the lead group on the exact section of smooth road where we had done the power/aero testing during the week prior. 

You might remember that this was the attack that started the ridiculous rumor about him having a motor in the bike...the attack is simply phenomenal to watch!  


Speaking with him after the fact he had some really awesome things to say about that day, but most impressive was his mindset.  He told us, 'I remembered what you said about the advantages of technology, I felt like I was on a time trial bike while everybody else was chasing me on equipment from the Eddy Merckx era..'  which was something we had told the riders over and over.  In the end, it wasn't an equipment advantage, but rather a technology and knowledge advantage that had translated into an incredible confidence and belief.

Cancellara later commented to the media that 'Roubaix will never again be won on the old wheels,' as there was 'too much advantage' to the new technology.  Michael Hall, Director of R&D now at Zipp said at the time, 'I think we just created the future.'  


Fabian has turned out to be thus far correct about the new technology.  2011 Roubaix was won on a Mavic Roubaix wheel nearly identical in all measurements to that original 2010 wheel.  In 2012, 2013 and 2014 was won on again on the 2010 design wheel.  Best of all, the frame makers during this time joined the trend and pushed tire clearance further.  For 2014 the race was won on a 30mm rear / 28mm front tire and looking to 2015 we are working with more than half a dozen teams on gauges, pumps and other inflation related items and it is brilliant to see many of these teams running 30mm tires front and rear.  The conventional wisdom has changed, and the riders will be faster, happier and less likely to suffer equipment issues on their fatter, lower pressure tires.  

Notes: I spent 15 years developing racing wheels at Zipp with the most amazing team of engineers and technicians imaginable.  This story is about the teamwork between manufacturers, teams and athletes, but is more deeply a personal story reflecting my coming of age in understanding the importance of tire pressure optimization, the opportunity to improve pumps and gauges and ultimately the need to not just solve the technical problem, but also to educate and empower the mind so that athletes can not only make the best possible decisions, but can understand them and truly believe in them.  In many ways this Road to Roubaix was the first step in my buying and resurrecting SILCA. 

Thanks for reading!

- Josh


  • wldbmmprp

    Road to Roubaix– SILCA

  • Mark Petry

    this is a classic article and new insites are gained visiting it now and then, thanks Josh and Silca !

  • David Lilja

    Hi Josh,

    As I begin watching today’s Sunday P-R highlights from last week-end what can you tell us about Silca’s role?

    Which of the men’s and women’s riders used Silca bar tape or any other Silca products we can buy from you?

    Most of us out here in the non-Pro world can not test equipment like the Pros can.

    Now that P-R winners are riding on aero-carbon wheels you must be proud of your previous work at P-R! Surely, as tire pressures seem almost key to winning on cobbles now especially.



  • Brian

    Great story. Fascinating history..

  • Tom

    This was a compelling tale of courage, innovation, testing persistence, and advocacy. Sports like cycling occur at the nexus of technology, nature, and human physical and cognitive abilities. You can’t just invent a better mouse trap, you have to convince humans to use it correctly and believe in it. My favorite part of the story was discovering the difference in pump pressure readouts. The whole deal could have been scrapped there if not for the chance discovery of that small, hidden problem. This is a game of millimeters. I learn a lot from listening to Josh here and on his podcast, and I buy Silca products not only because of the science, but because I believe they will make me faster.

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