Silca's 'Ultimate Tubeless Sealant' is made from recycled carbon fibre

I’ve had my HED vanquish 6s set up with Muc Off tape and Silca sealant since April, maybe early May without issue.

I spent a good amount of time cleaning up the original tape and some orange seal that had gotten under the tape. Retapped with 2x layers of muc off, set the tape with a tube and dumped the sealant in.

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Mine took about 2 months to be an issue. YMMV but it wasn’t an immediate problem. Also, my wheels are 303 S so it’s conceivably possible they use cheaper tape there since it’s a budget wheel :man_shrugging:

They are not that transparent. At their prompting I left a product review on their sealant with photos politely pointing out the issues with rim tape that caused sealant to leak into both of my new Roval wheels. They sent me an email back stating they had never heard of this and there was nothing in the MSDS of their product that would cause the rim tape to degrade. Of course my review never appeared on their website.


Lame. And definitely unfair of them. As of now I definitely regret this purchase.


Thanks for sharing. I just got a new set of wheels today and was trying to decide if I wanted to take the risk. Them deceiving you about a known issue and not posting your review is the straw that broke this camel’s back. I’ll be sticking with Orange Seal.


So this stuff sucks.

Just took my wheels off to check.

Tape seemed beat up but like it was still holding. It’s original Zipp tape do I didn’t want to take it off if unnecessary.

What I think is happening is that this carbon fiber balls up horribly, then probably acts as an agitator inside the wheel. I’ve only had it in my wheels a few weeks. There was pretty much no “free” carbon fiber strands left. A few sporadically around the wheel, but not near enough to actually stop a leak. As you can see, it all clumped together. Plenty of sealant in there, and it sealed fine, but the big benefit, and the reason I bought it, to seal big holes, is not going to happen.

Check out the pics

Recommend NOT purchasing this stuff. Good idea perhaps but does not work for me.

Going to ask for my money back. Switched back to Stan’s.


How long after install was this? Which tires? New or used? Trying to understand if anything might be related to the Silca blog post. The tape seems to be the type that the Silca sealant “eats”, but that’s obviously not the main issue with your set-up as tape looks pretty good.

ENVE doesn’t list Stans on their approved sealant due to ammonia content (even though that’s what I was running before this. I guess it’s Orange or maybe Effetto now.

Has anyone had this work properly for 1.5-3 months?

I ordered this June 19th. Installed in a few days later with brand new Conti Terra Speed 40s. The tape was in great shape when I installed it… So this stuff is definitely tearing it up. Seems like quality tape though that is holding.

Switch to orange seal at least! Ime superior to stans for road

Curious anyone on this thread not have the carbon ball up after it’s been in there a few weeks? I had this sealant in a few tires and literally have never seen it not balled up after application.

Maybe its great if you can replace your tires and sealant before every race, but as a long term thing for the vast majority of us, it looks like the main benefit of the carbon fiber is gone after a couple weeks and may actually be damaging.

I’d think there is at least a chance the carbon could still serve its intended purpose of obstructing flow out of a puncture when balled up. Doesn’t seem like it would be nearly as effective as the free strands floating in fluffy white foam though.

I won’t be using this sealant any more regardless.

I’m in Leadville for the LT100. Today I was able to speak with Josh directly at the Silca booth at the Expo. He didn’t say anything really new, but he does think the carbon balling up is related to too much carbon in the initial batches. This in turn was damaging some types of tape. I did ask him about the Muc-Off tape but he wasn’t certain (my own experience so far has been ok with Muc-Off tape). He mentioned that the equipment that injected the carbon fiber to the bottles was actually clogging from the carbon fibers and led to the issues of variable amounts in the early batches.

Looking at the bottles of sealant at the Expo there was no question way less carbon in them compared to the two bottles I had initially purchased. Josh handed me a couple of bottles of the Replenisher for free which was nice. Hopefully the early kinks are just that and that the sealant starts to work as intended with the changes, but time will tell.


Thanks for the info.

Sounds like this is then the case. However, I don’t have an old batch, mine matches their supposed “good” on their blog.

In any case, thanks for reporting what he said! Hopefully there is a solution. It isn’t a bad idea, but as it stands, it isn’t just worthless, it is actually causing damage. At least in my application.

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I’d be curious to know why they don’t just recommend more replenisher for just about everyone. Too much carbon concentration is bad as has been seen. Is there a problem with too much replenisher? I’m guessing slower sealing, but that would probably still seal better than a giant ball of carbon.

Doesn’t seem like adding more replenisher fixes anything regarding the balling up carbon. It’s not drying out and then balling hp, it balls up before it can even dry.

The blog post talks about an ideal 5-7% carbon content and about how different things (reaction with certain tires, leaky sidewalls, excess carbon content from production) can cause a higher carbon content which leads to the carbon balls. Of course, I don’t know if that’s the cause or not, but that’s what Silca claims. If that’s the case, it begs the question of why not run 3-4% carbon in the mixture (e.g. dilute with replenisher)?

I am curious how just the replenisher would work without the carbon… It clearly tacks up quickly, I wouldn’t be surprised to see it on parity with the likes of stans or orange seal.

I don’t think all replenisher would seal much. It’s just latex. You need something to clog the hole. Most use ‘glitter’ and Silca uses carbon fibers. It just seems like too much carbon in the ratio is proving bad for a lot of people, so why fly so close to the sun? Dilute the mixture instead. I don’t know if that would work. Maybe I should send it in to AJA (Ask Josh Anything).

I’d say the biggest issue is knowing what 3-4% means. It seems like than can QC the CF content very well and are still getting it wrong in new batches based on peoples experiences. It might be more than just a % issue and also a CF length issue causing the initial balling