Sealant Update

First of all, I want to send a huge thanks to all of our loyal fans and customers who helped make SILCA Ultimate Tubeless Sealant one of the fastest growth products in the history of our brand. I also want to thank everybody who has left detailed reviews both good and bad; and those who have engaged with us in trying to identify situations and circumstances where the sealant has been either exceptional or lackluster in its performance. 


Even with a 2-year development process, it just is not possible to test every single tire, rim tape, puncture object, etc. Your help and feedback are greatly appreciated as we continue to refine our processes on all our products in our relentless pursuit of perfection. 


What we’ve learned and our best suggestions for the ultimate no-flat experience.

 Bottling equipment headaches have caused some of you short sealant life. Our biggest learning curve, so far, has been that the carbon fiber is phenomenal at plugging holes that it has continually defied all traditional bottling equipment and mixing machine technologies. As a result, many of our early bottles went out with too much carbon, as the bottling equipment was insufficiently mixing the product while continually adding carbon. Those early inefficiencies left some of you with sealant that last only 4-6 weeks in the tire before thickening and drying out almost completely. Along with this issue, some of you have experienced little carbon balls forming in the tire during that time. These little balls are the result of too much carbon which sticks to other carbon once the sealant has thickened. The foam can no longer function properly to maintain and separate the carbon fibers. The solution is to add Replenisher to the mixture to balance the ratio between foam and carbon fiber. For a visual, here are two bottles, one with the specified 5% carbon fill and the other from our early production at 20% carbon fill.  If your bottle looks like the 20% bottle, please email us: and we’ll get some Replenisher out to you ASAP.

Strange interactions with some tires. We have seen some strange interactions with certain tires leading to a thickening of the sealant, plus a changing color. We are currently working on this issue with our chemist. If your sealant has thickened and turned orange or blue, this is from the sealant reacting with a mold release compound used on the tires during production. This only seems to happen on the initial installation of the sealant and can also be improved by adding Replenisher. However, the best solution would be to wipe out the thickened sealant and replace it with fresh sealant (reinstall).  We have found that these same tires have a similar effect on other natural latex sealants including both Stan’s and Orange seal, but the formation of carbon balls in our sealant makes the situation more immediately noticeable.  For optimum performance with the following brands of tires, we recommend replacing new sealant after 2 weeks of initial install. Sealant life for the second charge of sealant can be as long as 3-4 months.

    1. Specialized tires made in Vietnam
    2. Terravail Tires

Strange Rim tape interactions. We have seen some instances of the sealant interacting with printed rim tapes sourced from China. In this instance, the sealant leeches the printing from the tape. Some have seen the beginning of delamination, as well as the thickening of the sealant. We have seen similar reactions with Orange Seal, but not with Stan’s. Our recommendation here is to only use tensilized polypropylene rim tapes, which are typically bright colored and cannot be printed.  These tapes are much stronger than laminated tapes with printing; and have no interactions with any sealant that we can find. 

Tires with weeping sidewalls. We have noticed that insufficient rubber coating in the sidewalls can lead to a reduced sealant life. Very lightweight casing tires which ‘weep’ through the sidewalls will reduce sealant life on the initial install. This can be remedied with an immediate injection of Replenisher to re-balance the sealant. SILCA Ultimate Tubeless Sealant contains more latex than other brands, so it will thicken faster with the loss of its solvent. If the latex must coat and seal the insufficient casing of the sidewall, adding more sealant is only solution to remedy the sidewall and perform beyond that initial coating. Many of you have pointed out your experience with other sealant brands and that it’s not unusual for the tire weeping to last for days or weeks after initial install or had continual air loss; but SILCA sealant sealed the tire within minutes or hours and then held air pressure much better. This improved ability to seal is a powerful feature of this product, but we must then be sure to replenish the sealant for optimal performance on the road. We recommend adding 1oz of Replenisher when using the following tires:

  1. Rene Herse – All models
  2. Continental GP5000TL and GP5000TR
  3. Challenge – All models
  4. Vittoria – All Corsa series models
Now for the GOOD news

    While we’ve been learning the limitations of this new technology, we’ve also been receiving hundreds of amazing and positive stories and reviews.  We’ve learned that some combinations seem almost ‘too good to be true’ results and have since demonstrated in our lab that this performance is real! Primarily, the sealant seems to work most optimally with Panaracer produced tires. We have stories and now lab data showing the ability to seal punctures up to 10mm with sealant life equal to or better than stated on the bottle (3-4 months between ‘Replenishings’). These results seem to be linked to the high consistency of tires produced by this brand as well as the rubber compounds used in the casings. The fact is these tires are cleaned at the factory to remove mold release or other contaminates, which eliminates any chemical reactions with sealant. Similar results have been reported with Hutchinson produced tires as well. Tires with consistently excellent performance (including one Unbound rider who counted 5 punctures on one tire with only 3psi loss of pressure) are below:

    1. Panaracer Gravel King – All models
    2. WTB – All models
    3. Compass/Rene Herse – All models except lightweight casing variants
    4. Ultradynamico – All models
    5. Hutchinson – All Models
    6. Zipp – All ‘Made in France’ models


    Ultimately, I know that this level of transparency and complexity will turn some people away.  We’ve already had numerous customers tell us they are ‘going back to the devil they know’ with another brand to not have to change rim tape, add more Replenisher, or put any more thought into their tires and sealant than they feel is necessary. For those of you who’ve had a poor experience we truly apologize and have done everything we can to improve the experience.


    We completely understand the desire to make this easy, and we are committed to improving our technology to ultimately make it easy as well.  However, I also remind everybody that the reason this product is so exciting is that it’s also demonstrably better than what has existed before. In the pursuit of better, we also must do things differently than what has been done before, which presents many new unique challenges. We are not going to make a product that seals holes 2.5X larger than Stan’s or Orange Seal (See independent video review of this happening) by doing the same thing that they are doing.  So, for the rest of you who are still interested in better, here’s our latest update:


    We have invested in new mixing and bottling equipment which was installed early June resulting in a significant improvement in product consistency. We are now able to control carbon content between 5% and 7% which we know to be the optimal level.  We have also tweaked the formula of the Replenisher to contain slightly more solvent so that it can better replenish the sealant thickening in tires (noted in the cases above).  We are also working with the rim tape and tire manufacturers noted above to determine exactly what components of the sealant are involved in these adverse interactions in the hope that we can tweak our formula slightly to eliminate or significantly reduce any adverse interactions.


    • Travis Verhoff

      @Chris, DT Swiss offers a rim tape that is printed so it is not the Tensilized Polypropelyne tape that would be stronger. That being said it does appear to be an issue that is being resolved with the bottling updates we have made. The rim tapes have not had any chemical reaction we can find but the abrasion from the carbon balls when the carbon is too dense can cause this delamination. Out an abundance of caution we would still recommend upgrading the rim tape but it shouldn’t be an issue moving forward with stock tapes as well.

    • Chris Singleton

      The rim tape issue is far more than ‘rim tape from China’ it destroys DTSWISS tape on near new wheels, and destroyed rim tape on brand new ZIPP 303 firecrest wheels that were fitted with new Pirelli cinturato M tyres and filled with silca, sub optimal when in the back of nowhere and massive fail with goo inside the rim and around the spoke nipples, be interesting to see if they fail due to corrosion, and then there was the first fail on DTSWISS wheels sitting on the start line of a road race watching goo come out of the nipples, luckily could borrow a wheel before the gun

    • dwight cheu

      I think for a tubeless newbie, having to pour the sealant into a partially installed road tire rather then via the valve stem would be challenging — especially with tight fitting tires. I’ve installed a couple dozen tubeless tires, so I’ve learned a bunch of tricks / techniques through YouTube and trial & error… soapy water, taking the valve core out, making sure the tire is in the center channel, etc.

      Having to get the last part of the 2nd bead over the rim on a road tire with 2+ oz. of sealant sloshing around is even more of a faff. While wrestling the tire, I lost a bunch of sealant, so I added about 1/2 oz more to replace what was lost.

      When installing the tire & seating the beads with my air blaster — keeping the valve at the top and the sealant at the bottom was certainly key.

      The final result was great, though. Seated the tire and held air on the first shot. With the identical tire (a new 25mm Michelin Power Cup tire & a LightBicycle AR56 rim), I was getting an imperceptible leak that eventually deflated the entire tire in 2-3 days. This was after multiple mountings using Muc-Off sealant.

      The Silca sealant seems to have made the difference as the tire has held air for over a week.

      Thanks, Silca!

      p.s. I wonder if it would be possible to pour the sealant through the valve with the valve core out (not using a syringe, etc).

    • Daniel

      Thank you for being this transparent. I have the feeling from my own experiences with road and gravel tubeless that tyre brands, rim tape and the sealing agents influence each other more than is typically communicated. Therefore, and as someone else said already, it would be great if you could update this post with any recommendations regarding rim tape, e.g. the MucOff translucent one.

    • Zak

      I second James’s comment. More companies like this with engineering on the forefront. The world would be better off with this kind of transparency and less marketing BS. Thanks Silca!

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