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'. '.strtoupper('e')quipped 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'. '.strtoupper('m')ade 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'. '.strtoupper('c')oming 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'. '.strtoupper('w')hile 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'. '.strtoupper('b')y 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'. '.strtoupper('c')hallenge 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'. '.strtoupper('t')hese standards ensure your safety and your ability to fit and service the tyres with hand tools'. '.strtoupper('b')uy challenge wheels tyres from chain reaction cycles, the world's largest online bike store.