Bikes and Tech
Photo: Specialized

Specialized’s S-Works Turbo RapidAir tires make road tubeless viable on the racecourse

Re-thought manufacturing method and road-specific sealant claimed to make Specialized’s new tubeless tire the rubber to beat

HARROGATE, North Yorkshire, England (VN) — By now we know the pros have been running tubeless tires at the world’s most illustrious races. Specialized recently made it official when it launched a new addition to its top-end S-Works Turbo tire range, the S-Works Turbo RapidAir.

The tire is designed to be run tubeless though is also compatible with a tube, and the brand is claiming it to be “faster, more comfortable, better handling” than anything they made before. Oh, and if that’s not enough, it’s claimed to be self-sealing and easier to install than their previous tubeless set-ups.

Given the popularity of the S-Works Turbo tubular, clincher and tubeless range with pros and amateurs alike, that’s some claim.

VeloNews met with Specialized representatives to make the case for why the RapidAir is the best race tire they’ve ever made.

Those of you that have jumped on board the tubeless tire trend will most likely have a horror story of a tubeless failure. You’re 80km into a ride, you puncture, the sealant fails to work, and the tire is so tight that you fight for an age to uninstall it and pop in an inner tube. Worse still, your hands are so cold, or you’re already so spent from training, that you can’t remove the tire from the rim at all.

Specialized says the RapidAir promises to put an end to all that. The tires have already performed well enough that Deceunick-Quick-Step riders opted to use it at the Tour de France. Much of the appeal comes from the low rolling resistance tubeless tires offer.

There does appear to be some legitimate science behind the claims for better gip, speed, and comfort, along with ease of installation. That all lies in the tire’s construction, and the sealant designed to be put inside it.

Clincher tires are manufactured in a largely standardized way, with the primary casing material being folded and layered, with the most layering occurring at the tread, where the casing layers overlap. A final puncture belt layer and tread pattern is then piled on top of the casing.

The RapidAir has shifted this established method however, by removing the central overlap point from the center of the crown, and shifting the point to where the casing layers ‘close’ to the sidewalls. An added wrinkle to the innovation is leaving a slight gap in layers either side of the tire’s crown, allowing a small pocket of space.

The idea behind this construction is that the thickness of the tire casing is shifted to the sidewalls, but leaves the puncture belt and tread pattern where it should be — at the center. This solves the issue of puncture-prone sidewalls, and allows the tread area to be more flexible and supple.

This combination of suppleness where the tire meets the road and rigidity at the rim allows for better ride feel when moving in a straight line, and more stability and improved handling around the bends. Indeed, Specialized are claiming the RapidAir to boast 6% better grip than their S-Works Turbo Clincher, and 18% more than a Turbo Tubular.

The removal of the overlapping casing from the tire’s crown also lowers the tire’s rolling resistance, making it faster. Specialized claim this simple re-invention to reduce the RapidAir’s rolling resistance by 13% over their Turbo Clincher, and 15% over the Turbo Tubular.

The new layer pattern, with the casing density shifted to the sidewall, not only offers more protection from those ride-ending sidewall gashes, but means that the tire should theoretically remain more airtight when being run it tubeless.

The layering pattern also adds an outward tension to the tire. When squeezing the sidewalls of an uninstalled RapidAir tire, it has an elastic feel. This outward tension makes the tire easier to install into the rim of your wheel. Combine this with the high-tensile material used at the tire’s bead, and you get a tire that locks onto the rim’s bead hook more confidently, and can withstand high pressures. Having had a go at installing the tire on a Roval rim, we can confirm that even the puny hands of a VeloNews writer can easily install it onto a rim.

Lastly, the second major development: the sealant. All the RapidAir tires are supplied with RapidAir sealant, which has been specially designed to be run at a high pressure (72psi+) with a road set up. This contrasts most tire sealant, which is designed for universal use on the trail, gravel, or road and cannot be run at such a high pressure. The RapidAir tire is also compatible with a standard sealant, though not at the high pressure offered by Specialized’s specific compound.

Whereas most sealant is made up of uniform size filaments with rounded edges, RapidAir sealant is comprised of a pick’n mix assemble of size, shape, and smoothness of particle. This mixture of filaments is claimed to be more effective when bonding the liquid to the rubber of the tire, and when bonding to surrounding filaments in the sealant. This strengthened bond lead to Specialized’s claim that it can plug a 3mm hole in a tire instantly.

Though we haven’t tested the tires yet, we were shown a shot of a RapidAir tire ridden by Michael Morkov (Deceuninck-Quick-Step) at the first stage of this year’s Tour, and there was a large hole in the rubber that had been plugged as he rode.

The RapidAir tires are available now, in 26mm or 28mm, and are compatible with the vast majority of readily-available wheels.

VeloNews Tech Editor Dan Cavallari has a set of RapidAir tires in for testing now. Check back later for a long-term review.