Tony Martin’s TT world championships win in Doha was notable for the “Panzerwagen’s” dominant performance, but his tire choice was worth noting as well: Martin eschewed tubular tires in favor of Specialized’s Turbo Cotton clinchers.
Tubular setups are nearly universal in the pro peloton because tubular rims are lighter than clinchers, tubular tires offer a supple ride quality, and, most importantly, tubular tires are somewhat rideable while flat, which makes them safer and allows pros to continue moving forward while waiting for the team car. But according to the tire team at Specialized that includes Wolf VormWalde (director of tires and tubes) and Oliver Kiesel (product manager for tires), clinchers are faster than their glue-up cousins — particularly the Turbo Cottons.
“The clincher tire with clincher rims has less energy loss from deformation, which makes it faster,” says VormWalde. “The Turbo Cotton tire is the fastest option we have. The cotton casing offers much more speed compared to a nylon tire or tubeless tire. The cotton casing material is impregnated in a latex solution, so it’s not cured rubber as it would be in a regular clincher tire.”
That means TT riders get better damping properties, yet the tire’s tread can be the same as it would be on a full-nylon tire. “This latex solution has less hysteresis loss, so there’s more rebound, less damping,” says VormWalde. “There’s less resistance to deformation in a cotton casing compared to a cured nylon casing.”
VormWalde and Kiesel say Martin’s not the only one using clinchers during time trials, either. Many riders on Etixx – Quick-Step run a similar set-up, as do a few riders on Tinkoff. Astana, another Specialized-sponsored team, doesn’t run clinchers because the team uses Corima wheels, which are tubular-only. But it wasn’t a fast sell for Etixx: Martin rode clinchers in 2012 at the Tour de France and flatted. It wasn’t until 2013 when Martin had more success on clinchers that the rest of the team embraced clincher tires, only on the front wheel at first. When Zipp released its Super-9 carbon clincher disc wheel, the team began running clinchers in the rear as well.
Martin ran a HED Jet Disc Plus wheel in the rear and a Roval CLX 64 wheel in the front in Doha. It’s no surprise that Martin ran the Turbo Cotton tires: In the VeloNews tire rolling resistance test (November 2015 issue), the Turbo Cottons were the second fastest tire we tested. The only tire that beat it was Specialized’s S-Works Turbo tubeless.
Kiesel says Martin ran a 24-millimeter tire in the front and a 26-millimeter tire in the rear. The CLX64 rim was designed to work with the 24-millimeter tire specifically: There’s an aerodynamic advantage to the clincher tire over a tubular, because the clincher tire has a straighter sidewall when hooked into the rim. This means air flows more smoothly over the tire and rim, whereas a tubular’s round shape would cause turbulence.
Since there’s so much turbulence in the rear regardless of tire choice, Martin used a 26-millimeter tire because the wider tire offers lower rolling resistance than a 24-millimeter tire.
This wasn’t the first time Martin has run clinchers and ended up on the podium. During his 2013 TT worlds win, Martin ran Zipp wheels with Specialized tires. And Martin used clinchers as early as 2012 at Valkenburg Worlds, again on Zipp wheels.