Challenge Gravel Grinder Tubeless Vulcanised TyreReady for the rough and tumble of gravel riding, this Challenge tyre is up to the task of keeping you upright and unrivalled over such loose and rugged terrains. Equipped with a flat centreline tread, it rolls like a dream with speed and confidence, while the raised shoulder knobs give exemplary traction when cornering and braking. Made from a dependable vulcanised 120 TPI nylon casing and reinforced with a Challenge's Puncture Protection Strip (PPS), this tyre provides the strength and sturdiness you need for a confidence-instilling ride. Coming complete with a fast-rolling diamond centre, this tyre is perfect for all-around gravel and adventure riding.Features: Tubeless Ready: Yes Use: All Around Gravel Size: 700 Tyre Width: 33mm Internal Rim Width: 17-25mm TPI: 120 Bead: Aramid Casing: Nylon Flat Protection: PPS BAR: 3.1-5.1 PSI: 40-75 Weight: 375gTechnologies: Vulcanized Tubeless Ready (VTR): The highest level of performance offered by car, truck and motorcycle tyre manufacturers is a vulcanized tubeless system. While this is an old technology for cars and trucks, for bicycles it is relatively new and did not even have an internationally accepted design standard (ISO or ETRTO) until recent years. By eliminating the inner tube it is possible to lower the weight and create a softer, more comfortable, more efficient, lower rolling resistance tyre system by running lower tyre pressure. Challenge started introducing Vulcanized Tubeless Ready (VTR) tyres in recent years because the ISO and ETRTO standards for proper VTR tire and rim fit have finally been completed. These standards ensure your safety and your ability to fit and service the tyres with hand tools. Buy Challenge Wheels & Tyres from Chain Reaction Cycles, the World's Largest Online Bike Store.