With gravel and adventure riding growing at the fastest rate in all of cycling, tire tread and volume options have proliferated. With tubeless technology and wider rim/wheel designs opening further breaking down boundaries and opening up new possibilities. Amidst this rush of growth, the Challenge Gravel Grinder Open Clincher remained a premium option for those who have been running standard clincher rims, running tubes. Challenge had borrowed the tread pattern for the Gravel Grinder from it's Chicane cyclocross tire and offered in larger volumes. Now, with Challenge finally offering a tubeless ready tire (TLR), the Gravel Grinder has reasserted itself as a fast rolling tire that can now take full advantage of it's shoulder knobs for greater traction in rougher terrain redefining the balance that the tire already owned in the gravel world. Taking advantage of the lower feasible pressures of tubeless Available in 700x33 (just like the Chicane TLR), 700x38, and 400x42mm, the Gravel Grinder TLR Tire offers options for more bikes, wheels, and conditions.

The Gravel Grinder TLR is built around a 120 tpi Nylon casing which is supple enough for the full size range from 33mm-42mm. A specially shaped and reasonably flexible tubeless rubber bead it built with an aramid core, so it has some pliability for reasonable installation yet doesn't really stretch. Challenge recommends a 15-19mm internal rim width for the 33mm, but a more contemporary 17-23 range for the 38 and 42mm versions. The recommended pressure range for each size varies as well, with 45-75psi for the 33mm, 40-75psi for the 38mm, and 35-60psi for the 42mm. These details matter so you can ensure your wheels and need match the proper size. Challenge is fairly conservative in their specifications, but they have tested to make sure you are safe and you won't damage your equipment, so we recommend you follow them.

The story of the Gravel Grinder design has always been told by it's tread pattern. The pointed diamond knob file tread center delivers excellent speed, especially with a little wear, but provides stability, straight line traction excellent power transfer in packed material and small loose material over hardpack. The distinctive edge knobs are directional for speed and hold while cornering on pavement or hardpack, but also aggressive enough to hook up in soft material. Now, with lower pressures allowed by tubeless use, these knobs will be more active for grip and traction, even in mud, making the Gravel Grinder even more effective and versatile on long distance rides or events where conditions can be variable.

The tubeless bead sets up well on rims with short depth bead seats (such as those championed by Stan's NoTubes) and ammonia-free sealants. For puncture protection the rubber is the only provided answer, along with the nylon casing. Challenge has yet to offer much more detail about the rubber itself, but early reviews demonstrated good puncture protection and tear resilience. Overall, we have been excited to see Challenge embrace tubeless technology. It truly enables a great tire to be more versatile and effective while meeting the width and volume requirements of today's gravel and adventure bikes and riders.