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Silca Ultimate Tubeless Sealant 32oz
Silca Ultimate Tubeless Sealant 32oz
Silca Ultimate Tubeless Sealant 32oz
Silca Ultimate Tubeless Sealant 32oz
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Silca Ultimate Tubeless Sealant 32oz

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Mfg PartNum: AM-AC-039-ASY-0102
rating(9 customer reviews)
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MSRP: $42.00
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Leverage The Power Of Recycled Carbon Fiber

SILCA Ultimate Tubeless Sealant uses the power of a foaming latex formula combined with chopped carbon fibers to boost sealing power even at higher pressures. Ultimate Tubeless Sealant contains 5% by volume, 6, 9, and 12mm chopped carbon fibers which have been reclaimed from recycled bicycles, carbon wheels, race cars, and aircraft components.

A unique foaming latex formula allows for the very lightweight carbon fibers to be evenly dispersed within the sealant while riding, which allows for a higher fiber content than possible with Kevlar or fiberglass.

Bundles of recycled carbon fiber are carried directly to the puncture by the sealant flow where thousands of micro-bubbles collapse on each other, depositing their high stiffness carbon fibers over the puncture forming a seal. During this process, the carbon fibers form a dam of fibers against the tire casing not unlike a beaver dam of sticks blocking the flow of a stream. This dam of high stiffness/high strength fibers has been shown to seal holes in testing up to 7.5mm, some 25% larger than conventional sealant technologies.

One thing to note is that Silca's Ultimate Sealant must be poured into the tire during tire install. Because of the high carbon fiber content, Ultimate Tubeless Sealant will plug any syringe or valve hole you try to pump it through.


  • The sealing power of a race-specific formula with the longevity of long-lasting formulas
  • Seals up to 25% larger punctures than conventional sealant technology
  • FiberFoam Technology uses a blend of 6mm, 9mm, and 12mm long carbon fibers which are 400% stiffer than glass fibers with better dispersion through the sealant
  • Effective down to 10°F / -12°C
  • 32oz replacement size

  • B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.



    Mfg PartNum: AM-AC-039-ASY-0102 


    Ordered by Most Relevant First
    5 stars
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    Really effective!
    by Anonymous
    Competitive Racer
    Portland, OR

    I have a bit of experience with a few different sealants, but this one probably is the quickest at actually sealing, especially on bigger holes or higher pressures (i.e. road tires). While the other sealants would spray a bit out of the tire as they were sealing up, in my one puncture with this sealant, I didn't even notice until I got home. This benefit does have one drawback - cleanup is a little messier when first installing, as it dries so fast, you can't just wipe up accidental spills like some other sealants. Also, you have to pour it into the tire, and not inject it through the valve because it's so good at plugging up.

    Reviewed 5/20/2024
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    Seams to seal really fast, buuut........
    by chainsaddiction29er
    Competitive Racer
    Aztec, NM
    6 of 6 customers found this review helpful.

    I have tried many sealants over the past 20+ yrs since tubeless came out and I do want to point out some traits of this sealant when you're considering this. My experience with Silca's Ultimate sealant has been mixed overall. The CF strands and latex mix make for a compelling sealant, right? Well, since using it, I've not had a single puncture or leak, so the sealant is doing it's job, right? Sort of. There are some annoyances and concerns about it's usage though. I still race MTB and often ride through goat head and cactus country quite a bit around here and will find both items stuck in tires occasionally but have not had pressure loss or issues sealing any holes since using this sealant. I'm waiting for a rock puncture to see what happens. Using Stan's many years ago, and seeing how watery and ineffective it truly was for me at sealing several small punctures during 2 different races, left me looking elsewhere. I dove into the dark underworld of making my own sealant for many years with great results and it would last ~2-3 mths. When Silca released this product, I thought it would be the magic elixir of sealants having the ideal combo of longevity and effective sealing. Here's what I found.


    1) Thicker consistency than some other brands.

    2) "Appears" to seal punctures and holes quickly.

    3) Price, considering what you get compared to some other brands.


    1) You cannot inject this Ultimate Sealant through any Presta valve, so you need to pull off tire from rim to add sealant. I suspect same applies for Shrader valves.

    2) Dries too quickly! After installing proper amounts into my MTB and road tires and rechecking 4-5 weeks later, I discovered almost all sealant was completely dried up already, leaving me disappointed:/ 5oz for MTB and 3oz in my 32mm Corsas, and both seemed to dry out similarly. I will say, temps had been quite warm 85-95F during that entire time so likely attributed this. But this is the area where sealant matters during rides and Silca indicates replenishment occurring every 3 months which seems far too long of a stretch.

    3) Clogs valves quickly. Days after installing sealant, I noticed pumping up my tires pre-ride, the air just wasn't going into tire quickly at all. Turns out, the 5 holes in my valve stems were almost completely plugged from sealant. This happened on both my road and MTB wheels. Cleaning valve holes out regularly resolves the issue, but for how long?

    4). Carbon fiber strands separate from latex sealant. As sealant dries up in the tires, the CF strands stick to the tire and don't stay suspended in sealant fluid. I cannot attest this being a bad thing yet, buuut, I don't see how those strands are going to help much when puncture occurs if they're already stuck to tire and not where puncture is and you're left with just the limited amount of fluid sloshing around inside.

    5). Environmental impact? So where are these CF strands going to ultimately end up? Landfill? Scattered out on trails? Will this CF eventually break down? Ehhh, not sure about that. Obviously we aren't talking about much volume of carbon here, but still. Is there a more environmentally safe filler/additive that could be used?

    6). Doesn't smell like fresh baked cinnamon rolls, but would be cooler if it did:)

    Reviewed 9/24/2023
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    Mixed thoughts, possibly a race only sealant
    by Michael
    Competitive Racer
    5 of 5 customers found this review helpful.

    Set this sealant up this summer on a pair of Zipp 303s wheels and Cannonball tires for training. Used 3oz sealant. After three weeks of use, mostly hot weather rides, likely 300 miles on the wheels I wanted to see how the sealant was doing as there where reports of it drying up fairly quickly and the carbon shreds clumping. Sure enough the sealant was almost completely dry and the carbon shreds where clumped up in 5-6 balls adhering to the tire. These where rides in Kansas, with heat approximately 90-100 degrees. Wheels stored in house otherwise.

    Decided to then use this on my race setup and assess one week later. Now on my 303 firecrests, continental terra speed tires with 2.5oz sealant. One week later and less than 200 miles of riding the sealant was not diminished but there was some clumping, but nothing significant. I decided to go ahead and complete a race with this sealant and setup the tires two days before. I really like the theory of the sealant and I think it could work very well in its current iteration as a race day sealant.

    It does clump some around my valve stem in the wheel and when you pour this sealant into the tire I would suggest pouring it quickly as the carbon shreds tend to settle quickly and adhere to the bottom of the cup.

    I really like Silca products, huge fan of their podcast and own many of their products. I think right now this is a great race week sealant but otherwise there is only downside when compared to Orange Seal. Review wise this is hard because to be an ultimate sealant it needs to not be limited to race specific applications. If this was sold as a race week sealant I would give it 5 stars but alas that is not how the product has been marketed.

    Reviewed 8/29/2022
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    I see why it was on sale
    by IsleofT.
    Cycling Enthusiast
    Los Angeles
    3 of 3 customers found this review helpful.

    As others noted, it is a pain to use if you like to inject through a presta valve. I'd assumed the carbon pieces were tiny, but, they totally sealed up my Stan's injector and I ended up tossing it.

    What spilled out from pouring it into the tires dried quickly and was a bigger pain to clean up than my normal sealant (Orange seal.)

    I'll probably save the bottle for big ride events. Seems like it might be okay for those but, not as an everyday sealant.

    Reviewed 11/30/2023
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    The Best Sealant Period
    by LongCaneRider
    Cycling Enthusiast
    Greenville, SC

    Usually I'm a frugal cyclist, not brand loyal and I go for the best bang for the buck... but sometimes a product comes along that is just so head and heels above everything else that it can't be ignored. Here's why it's so much better: I used this sealant in a set of Maxxis Ramblers. Had them mounted to the same wheelset for over 12 months. I was lazy so I didn't do any maintenance to the sealant over that period and probably put 100 miles per month on the tires. The Ramblers never flatted, but when I went to change the wheelset to different tires, there was still a hefty amount of wet sealant in there, probably more than 2oz... and I was confused. I was fully expecting, due to my laziness, that the sealant would be totally dried up.

    Here's what happened: the sealant made an airtight chamber for itself. It totally sealed off the inner part of the tire, rim, and bead so that it was 100% air tight. I then tried to think the last time I pumped up the tires but couldn't. It's possible that I only pumped up the tires a couple times in a year!

    This sealant is the absolute best on the market. As long as they don't change the formula I'm not going to use anything else. Yes it's more expensive than other stuff out there, but this time, it's worth it.

    Reviewed 6/9/2023
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    It worked where others did not
    by Anonymous
    Cycling Enthusiast

    I recently bought a bike which was "tubeless ready". The bike did come with tubes though. Fairly soon I got a puncture and decided to go full tubeless. I purchased tape and sealant from a competing brand and installed. The leak continued. I brought the bike to a bike shop and they installed another brand tape and sealant. Again the leak continued. The bike shop told me the tire while fairly high end had sloppy construction around the bead which caused a poor seal. I purchased and installed the Silca sealant and tape about two months ago (400 miles) and have only needed to top off the pressure once. Use is primarily light gravel and poor quality road.

    Reviewed 3/16/2023
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    Others work, this is the best
    by Anonymous
    Cycling Enthusiast

    The only thing that isn't fun about this one is that the fibers in it mean you can't use an injector. So you will need to be pretty comfortable installing your tire by hand.

    Reviewed 2/26/2024
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    Seems to be an Excellent Sealant
    by Mars Rover
    Competitive Racer
    San Diego, CA
    3 of 3 customers found this review helpful.

    Being a new product, there were limited reviews out there. But my go-to product - the CaffeLatex sealant - was out of stock everywhere and I've already tried nearly all of the rest of the sealants out there and not liked various aspects of them: they clot up into rubber marbles (common), they don't seal well (common), or in one case, caused the tire to start weeping sealant (very bizarre). There are definitely a lot of subpar sealants out there that tout themselves as being the best (not). I'm an off-road endurance cyclist (mtb, gravel) now focused on just gravel riding, training, events.

    THIS product - the Silca Ultimate Sealant - seems like a good product, and Silca doesn't ever make garbage products. It is a little quirky to install, since the size of its clotting fibers require pouring the liquid into tire vs my usual injecting it via the valve. Easy to make a latex mess when pouring, just requires care and attention to detail.

    Performance so far: I'm only 2 months into usage and I have not re-opened the tire to examine for rubber marbles/clots. No leaks so far but no punctures detected, so its sealing performance is unknown. However, no issues with sealant seepage via the sidewalls or leaking around the bead.

    We are heading into goathead thorn season in a month, so we'll see how both the tires and sealant handle them.

    Reviewed 7/7/2022
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    Ultimate sealant
    by Anonymous
    Cycling Enthusiast
    Los Angeles

    The silca sealant works. Better than other brands? Maybe. I've had good luck with it in my current setup. Other members in my club like Silca as well. I punctured my back tire a day after putting new tires with Silca and never knew it until getting home 20 miles later. The evidence was splattered all over the bike and my jersey. Tire held air and still does . Use the replenisher as scheduled.

    Reviewed 11/15/2022
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