This article originally published on BikeRadar
As a Clif Bar Cyclocross Team rider, Brady Kappius is one of only a handful of racers using Challenge's new handmade tubulars with cotton casings. Current Challenge tubulars have polyester casings, which are arguably more durable but a bit less supple than cotton, according to many riders.
Kappius and other Challenge-sponsored riders got batches of the cotton tires in September.
Like Challenge's current polyester models, the cotton-casing tires come with a thin layer of latex to protect against both water and cuts.
"I definitely feel like they're a little more supple," Kappius said. "They may lose a little bit of durability, but it's nice that they come pre-sealed. They are definitely a step up from Dugast [cotton] sidewalls, in that you don't have to seal it."
Challenge has four main treads that sell for $104-$110 with poly casings: Grifo, Grifo XS, Fango and Limus. Challenge also has a silk casing for the Grifo tread that sells for $170. Click through the gallery at right to see all the treads in both the currently available casings and the pro-only models.
The Limus is a newer tread for softer to muddy conditions.
The Fango (mud, in Italian) was created for muddy races, but has turned out to be appreciated as an aggressive, all-around tire, said Stefano Lumbaca, Challenge North America's managing director.
The Grifo is an all-conditions tire, and the Grifo XS has a file tread down the center with bigger knobs on the side for cornering traction.
Except for the 32mm Grifo XS, all the tires come in a 33mm width, with claimed weights between 400 and 415g.
The current polyester casings are woven at 300tpi for all tires except the Grifo XS, which has a 260tpi casing. (Tires are like sheets, in that a higher thread count generally means a higher quality tire.)
The cotton tires will likely have 300tpi casings across the board.
All of Challenge's tires are designed in Italy and made by hand in Thailand. All of the tubular tires have a seamless latex inner tube, which Lumbaca said is unique and proprietary to Challenge.
"We are the only ones who can do that," he said. "Others have a long pipe, that is turned and glued together. Ours is literally built out of one piece."
Lumbaca said the cotton casing should become available in all of the production models for next season. For now, though, you can spot them under Cal Giant, KCCX and Clif Bar team riders.
Pro riders say the cotton casings on the team-only Challenge tubulars are more supple than the current polyester casings