This is the Challenge Gravel Grinder Open Tubular/Clincher tire for Cyclocross, gravel adventure, and all around in between fun riding. The open tubular means that it is the same suple handmade casing featured in the Challenge Tubular tires raced by the world's top pros.
When searching for a Tubular or Open Tubular, consider the following factors, all of which play a role in the tire's performance.
- Tubulars and Open Tubulars: Tubular tires are, well, tubular. They are sewn shut around a Seamless Latex Inner Tube, already in a tube shape, and are mounted and glued directly on a rim, rather than around a tube. However, they require a purpose-made tubular rim that would usually only be used on race day to avoid damage. Open Tubulars mount like a standard clincher, but are made using the same artisan Handmade process as our Tubulars and maintain most of the suppleness and ride quality gained from a Handmade Tubular.
- Non-vulcanized: Ultimately the major difference between a Handmade Tubular or Open Tubular and the majority of clinchers is that it will avoid the heat and pressure process called vulcanization, which most tires undergo in production. It is used to bind the materials, but compromises the ride quality when the rubber gets stiffer. Treads are hand-glued onto Challenge Tubulars and Open Tubulars, and the latex and rubber maintain their ideal quality.
- Thread count (TPI): Thread count plays a major role in the weight, suppleness and durability of Tubulars and Open Tubulars. The higher the number of threads per inch (TPI), the thinner each individual thread, making a thinner and lighter casing and a more supple tire. Our lower TPI casings are thicker and more durable.
- Casings: Challenge offer casings made from silk, cotton or polyester. Silk provides the highest ride quality, with threads so fine we don't measure the thread count, and is stronger than cotton and polyester. Corespun cotton casing is lite and supple, and available up to 320TPI for maximum control and performance. SuperPoly and Poly polyester casings are less expensive and more durable, still providing the qualities of top-end tubulars.
- Rubber: Challenge treads are made from locally-sourced natural rubber in our own factory in Thailand. Not only is natural rubber more supple than synthetic rubber — which accounts for the majority of the world's tire production — the grip is far superior.
- Puncture Protection Strip (PPS): An extra layer of uniquely-crafted fabric with highly resistant properties sits between the casing and the tire to reduce the risk of punctures. Tires intended for use in intense conditions with a high puncture risk are reinforced with a second PPS layer beneath the casing.
Tire Type: Clincher
Compound | Casing: SuperPoly
TPI (Threads Per Inch): -
Puncture Protection: Yes
Inflation: 45 - 130 PSI
Weight: 355g (700c | 36mm)
This product was added to our catalog on March 7, 2018