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Tony Martin (Omega Pharma-Quickstep) will ride a new clincher tire from Specialized in Saturday’s 54km individual time trial at the Tour de France.
Martin and his sponsor, Specialized, experimented with clinchers in time trials in 2012, forgoing traditional tubular tires in search of decreased rolling resistance, but quickly returned to tubulars after a string of unfortunately timed flats. Testing has shown that a thin, flexible clincher can decrease rolling resistance relative to even the fastest tubular tire, but the small gains were not worth the increased flat risk.
The new Turbo Cotton has won over the German time trial specialist once again. Martin rode the tires in the Tour de Suisse, flat free, and will ride them again on Saturday. VeloNews received an early set of the tires, which will be available to consumers this fall, and has been testing them on the roads around Boulder, Colorado since early June.
Lennard Zinn’s review of the Turbo Cotton tires
This fast-rolling 25mm tire is Tony Martin’s time trial weapon, and Guido Trentin and Martin won stages 7 and 9 of the 2014 Tour de France on the tubular version with the same slick center tread. On road stages, Omega Pharma-Quick Step is on the Turbo Allround2 tubular, and Mark Cavendish raced all last year on TT version, sporting the same slick center tread.
After riding these for a couple of weeks, I can say that I’ve never ridden a nicer clincher. Cornering is fantastic, road feel is great, and when it’s wet, grip is exceptional — closely approaching that of a top-end cotton tubular.
The Turbo Cotton is made by Lion Tire (a subsidiary of Vittoria) in Thailand with that company’s 320tpi Polycotton casing fabric and Specialized’s proprietary puncture breaker material and Gripton tread compound. The tread design is borrowed from the time trial tubulars Specialized provides its top pros.
The slick center tread makes a difference, according to Specialized, albeit a small one. Specialized claims to have measured the difference in rolling resistance on a drum at 0.2 Watts at 30kph over its tread with dimples in the tread center.
The dual-compound Gripton tread strip has new rubber formulations for the center and shoulder; the new polymer for the slick center strip is claimed to provide an additional ~15 percent reduction in rolling resistance.
An open tubular is built with the same unvulcanized, filament-wound casing and hand-glued tread as a premium racing tubular, but instead of being stitched closed around an inner tube to make it a tubular, Kevlar beads are laid on it before the casing edges are folded over, thus making it a clincher. It is more supple than a standard (vulcanized) clincher, because the individual threads are thinner, and they are not stiffened by being heated in a mold (vulcanized) to harden the rubber and stick all of the tire parts together into a single unit. Instead, when the thin treads are wrapped tightly around a drum, liquid latex is brushed over them to stick them together yet still allow them to move individually to conform to tiny bumps in the road surface. The tread strip is vulcanized individually (to give it durability) and glued onto the casing by hand, while it is inflated on a rim.
On an Ultegra rim, the Turbo Cotton tires I rode measured 24.8mm wide.
Suggested retail price: $80
The scoop: Supple and light 320tpi open tubular clincher with a slick center tread with small shoulder sipes
Pros: Great grip, smooth rolling, and low weight
Cons: Price. Durability?