Silca, the American producer of lovingly designed pumps, tools and accessories, has applied this same forensic design approach to tire sealants – with the result being the cheekily named Ultimate Tubeless Sealant.
Leading stats say it is rated to seal +6mm holes (up to 8mm) and up to 6mm holes at road pressures of 80-90 psi. In terms of longevity, the sealant can last an entire year – with the right care – while the tested temperature range goes down to 10°F / -12°C. It could drop, but it hasn’t been cold enough around Silca’s headquarters this winter to know that.
In terms of price, the sealant is $38.00 / £36.00 for a 32oz bottle, while Stan’s No Tubes Race Sealant is $44.00 / £40.00 for 32oz and Wiggle’s house brand , Lifeline, will sell a 950ml bottle (similar size) for $33.99 / £22.99.
You can order the sealant from Silca’s website here, but what’s really fascinating is what Silca has done with its formula.
How does putty work?
Most sealants work by taking natural or synthetic latex and diluting it with some sort of solvent and adding antifreeze. Sometimes the antifreeze is the solvent, which streamlines things. To increase the sealing power of their sealants, many companies add particles to their mixtures to help seal cuts and punctures better. These can be anything from glitter and nuts to microplastics and fiberglass.
Silca’s research has shown that often these particles can struggle to reach the puncture site, with the wheel essentially acting as a massive centrifuge, pinning the particles in place against the tire carcass, unable to move.
To address this limitation, Silca’s approach was twofold. First, a foaming solution was developed instead of just a liquid. By observing the performance of the Effetto Mariposa Caffelatex sealant – a foaming sealant – Silca found that it was a much more efficient solution for particle transport.
Second, it needed to use a particle that was super light and therefore better able to still move around the solution – despite the centripetal force of the spinning wheel. For this, Silca opted for unglued carbon fiber.
Not only are these supposed to be able to reach the puncture hole more efficiently, but Silca says they can also stack on top of each other, much like a dam. This is especially useful for high pressure systems. If you get a puncture with a road tire, the sealant will probably seal very easily at low pressure.
Then, when you inflate the tire, you may break the seal, but the carbon fibers will again build up on themselves, closing up and making the seal stronger. Even on very narrow tyres, Silca says this process means their sealant can ensure that punctures stay effectively sealed at higher pressures.
Most sealants use some form of antifreeze to keep their particles in suspension, which leads to a trade-off: increase the proportion of particles and the sealant will seal better. However, this means that the putty will also dry faster and will need to be refilled more often.
You can see this directly with different sealant brands offering different products for maximum protection or maximum endurance.
With the combination of carbon fiber particles and Silca’s foaming solution being as effective as claimed, the American brand believes it can offer superior puncture protection to competitors’ race sealants, while still not not having to make the same sacrifices in terms of longevity.
The claimed average maintenance schedule of 3-4 months (potentially a month more or less depending on whether you live in cool and humid or hot and dry conditions).
Also, since the main limit to longevity is fluid drying, Silca supplements its tubeless filler with a tubeless replenisher. This allows you to refill the tire directly through the valve – other similar puncture protection sealants tend to need to be poured directly into the tire.
Although the Silca sealant is priced quite competitively against other high performance sealants at $38.00 / £36.00 for a 32oz bottle, the replenisher price seems incongruously high. On the Silca website it’s currently down $12.00 / £12.00 for a 4oz bottle.
This puts the restock at $3.00/£3.00 an ounce – which is significantly higher than the sealant’s $1.19/£1.13 an ounce. It’s true that the replenisher is labor-saving, being simply injected directly through the valve, but for that price difference, many will probably stick with the sealant.
When it comes to knowing if your sealer has dried out, averages are all pretty good, but sometimes it’s nice to be a little more reassured than that. Less effective sealants can be drawn through a syringe to be checked. But since that’s not an option with Silca’s Ultimate Sealant, they suggest weighing your entire wheel once you’re ready.
Then you can just weigh the tire periodically and add another 2 oz – or whatever your setup needs – once that weight has been lost from the system. Asked if tire wear makes a significant difference to tire weight, Silca said they didn’t find the effect large enough to be an issue.
Many antifreezes developed for the automotive industry can be very harmful to the environment. As part of a sealed system, they are, for the most part, easily contained and easier to dispose of in a way that limits the damage they cause to the environment.
It’s still not great, but when you compare that to the de-icer used on planes that gets sprayed liberally all over, the negative impacts are much worse. Therefore, a lot of work has been done to make these defrosters more environmentally friendly – and it is from these defrosters that Silca gets the antifreeze component of its sealing solution.
The carbon fibers used in the filler also come from recycled sources. At present, it is quite difficult to effectively recycle carbon fiber from cars, planes, etc., so the supply is relatively low. But with more brands, like Silca, finding an application for it, hopefully it’s something that will grow.
Since the carbon used is bio-neutral and the antifreeze is non-toxic, Silca says the sealant’s environmental impact is less than that of wearing the sole of a hiking shoe on a trail.
We have a bottle of sealant on the way and will post a review as soon as we have the measure.