Silca launches a tire sealant made from recycled carbon fiber

Silca Ultimate tubeless sealant
(Image credit: Silca)

Silca has developed a new tire sealant that takes an alternative approach to seal punctures on the trail. While the majority of the best tubeless tire sealants use a similar approach, utilizing a fluid latex to carry a particulate to plug any holes. Silca has taken a slightly different approach.

Most sealants are a balance between performance and longevity. Silca claims to offer the sealing powers of race sealant with the longevity of a endurance sealant with its confidently named Ultimate Tubeless Sealant. 

Silca's approach looked to address the balance between effectiveness and longevity and uses a foaming, rather than liquid, latex formula to carry chopped Pyrolized carbon-fibers. Silca opted for carbon-fiber due to it being lightweight enough to be carried by the foaming latex to give better coverage within the tire and improved delivery to the puncture location.

We already know that carbon has great stiffness to weight properties and Silca claims that by using the combination of foam delivery and 6, 9, and 12mm chopped carbon fibers, its Ultimate Tubeless Sealant is claimed to seal holes in testing up to 7.5mm. Silca states that the sealant is so effective that it's actually impossible to inject the sealant through the valve, instead it needs to be poured straight into the tire.

Silca Ultimate tubeless sealant

Silca claims that the stiffness of the carbon-fibers means holes begin to seal very quickly to minimize air loss (Image credit: Silca)

With an ever-increasing demand for environmentally friendly credentials, many sealant brands have moved away from plastic particulates. The nature of carbon fiber is also under scrutiny when it comes to production, so rather than manufacturing new carbon Silca is sourcing its carbon by recycling old carbon bike frames, amongst other end-of-life carbon products. 

The lifespan and replenishment process of Silca's Ultimate Tubeless Sealant is a little different from other sealants as well. Depending on climate and formulas, most formulas can last anywhere between six months to just two weeks. Silca says its sealant will last roughly 120-180 days, however the sealant life can be extended further using Silca's Ultimate Replenisher which increases the claimed longevity of the sealant up to a year.

The replenisher is a version of the sealant containing no carbon fiber so it is easily injected into the tire through the valve. Silca recommends that it should be added every three months in order to keep everything liquid and ready to seal within the tire. 

Silca recommends using 5 oz of Ultimate Tubeless Sealant for a 29er mountain bike tire between 2.25- and 3-inchs. The first dose of Replenisher is 2.5 oz, then 3.5 oz and 5 oz for the final refresh. Riders in warmer climates may need to use the Replenisher more often while cooler conditions will experience a longer interval between refresh.

It's not cheap although if the claims ring true on sealing ability and longevity the extra cost could be justifiable for riders looking for a dependable setup that requires little attention. Silca will offer its Ultimate Tubeless Sealant in 8 oz, 16 oz, and 32 oz bottles which will retail for $18, $24, and $38. The Replenisher will come in 4 oz bottles and cost $12 each.  

Graham Cottingham
Senior reviews writer, Bike Perfect

Graham is all about riding bikes off-road, based in Edinburgh he has some of the best mountain biking and gravel riding in the UK on his doorstep. With almost 20 years of riding experience, he has dabbled in downhill, enduro, and gravel racing. Not afraid of a challenge, Graham has embraced bikepacking over the last few years and likes nothing more than strapping some bags to his bike and covering big miles to explore Scotland's wildernesses. When he isn’t shredding the gnar in the Tweed Valley, sleeping in bushes, or tinkering with bikes, he is writing tech reviews for Bike Perfect.

Rides: Cotic SolarisMax, Stooge MK4, 24 Bicycles Le Toy 3, Surly Steamroller

Height: 177cm

Weight: 71kg