Finish Line Claims New Mountain Bike Tire Sealant Will Never Dry Out

Finish Line is marketing a Kevlar-based, tubeless mountain bike tire sealant they claim will never, ever dry out.

By Greg Heil
March 21, 2018 Last Updated: March 22, 2018

8 comments

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Finish Line is now selling tubeless mountain bike tire sealant, and they claim that their formula will never dry out. As a result, they claim there’s no need to refresh the sealant every few months, and that the “sealant will last the entire usable life of the tire.” This is a pretty bold claim that we hope to put to the test ourselves.

Finish Line says the sealant is “naturally non-toxic, hypoallergenic, and safe for carbon fiber rims,” since it doesn’t have any liquid latex or ammonia in the solution. The company also claims the sealant is much easier to clean up as a result.

How is this possible? Finish Line has created a technology they call “FiberLink,” which uses Kevlar fibers to plug any holes or punctures that may occur. “As the tire flexes while it is ridden, the FiberLink™ mesh tightens and reinforces itself, creating a confidence-inspiring seal that will last ride-after-ride,” according to Finish Line.

Finish Line tubeless tire sealant is available in 4oz, 8oz, and 1-liter bottles, and it’s even sold in 1-gallon jugs for shop use and rental fleets. The 4oz bottle sells for $8.99 online, the 8oz bottle for $14.99, the 1-liter bottle for $39.99, and if you want to go all the way up to a gallon, it can be had for $139.99 on some websites.

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8 Comments

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triton189 2015
Mar 21, 2018

At those prices I'll just keep refreshing my stans.

0 reply

Runeshadow Indiana // 2020
Sep 1, 2020

Finish Line tubeless sealant did not fare well. They started shipping out new labels to put on the bottles. They removed the statements about never drying out, and lasting the life of the tire. They also doubled the recommended amount to use. It’s hard to sell, with Orange Seal and Stan’s sitting right next to it.

mongwolf Mongolia // 2011
Mar 22, 2018

Greg, any info available about how much you should use per tire (and of course tire size)? I guessing the 4 oz bottle is supposed to do two tires and the 8 oz four tires etc. If so, and if it really lasts for the life of the tire, then that is quite reasonable pricing. And who doesn't love the idea of put it in once and forget about it. That is certainly worth the price points they are listing.

Bike Nerd Colorado // 2017
Aug 18, 2018

I tried Finish Line sealant and it just doesn't seal punctures well. After just a couple a months, I had to convert back to Stans. Thumbs down!

EricRybarczyk 2015
Mar 22, 2018

I'd like to read the results of a long term test. As others have noted, if it really lasts a season or a set of tires then it would be worth that price.

Slyham Arizona // 2015
Mar 23, 2018

If testing can verify the claim then this will be my new sealant.

sissypants 2015
Mar 21, 2018

So it may never dry out, but the utility of the sealant will decrease over time as the kevlar fibers in solution are packed and get stuck. This applies to all sealants that use solid mediums suspended in liquid. There just isn't scientific long-term testing data to determine whether latex-based sealants or bead/fiber-suspension sealants perform longer/better.

Help info and explanation BB. Thanks. That being true about kevlar fibers, I guess the real/next question is whether the sealant truly lasts the life of the tire for most people. If it does, then the packing issue of the fibers is a non-issue.

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