Challenge once licensed post-Pirelli years Clement Tire, the famed 'cross tire maker. In doing so it picked up several key tread design cue from Clement. As a result, one of the most closely duplicated cyclocross tire treads of all time is that worn by the Grifo. The best all-around cyclocross tire ever created excels in wet or dry, soft packed, rocky and root-infested courses, grass, and more. The Grifo features fast rolling, biting knobs and a center section that offers excellent pedaling and braking traction. Challenge H-TLR tires meet the new ETRTO and ISO standard and are hookless compatible, and can be used with a tube or as tubeless with hooked bead rims as well. It is designed to be complaint with UCI rules (33mm WAM) with most rim designs featuring an internal rim width up to 23mm. Handmade TLR tires from Challenge are best combined with the Challenge’s Smart Tubeless Sealant, which protects the natural properties of its components for a longer lasting performing tire, while further enhancing puncture protection and air tightness.

Challenge builds the Grifo Pro Series TLR tire with it's 300 tpi SuperPoly casing, a lightweight fine weave of soft polyester fibers that is both supple and resilient- perfect for cross racing. You get added protection from the PPS puncture strip, which is constructed like a fabric, with properties that match the casing for excellent ride consistency. The components react, responds and roll faster as a result of this combination- which is the ideal counterpart to the Grifo's loose-to-mixed surface purpose. It gives that little bit of speed advantage combination that comes from lower rolling resistance and rider confidence.

Challenge calls for a pressure range from 26-35 psi. Rider weight and actual use will determine what works best for you, but we recommend starting at 29-31psi. We find that going softer is best on rough hardpack when you need more overall footprint and grip. The tire is much faster when firm enough to really maximize the tread. Going softer may improve cornering, but won't really assist you much in sand or mud. Classic cyclocross riders carried and ran more, knowing that this approach was faster than riding. Of course these riders also excelled at mounting and dismounting, skills that not everyone can master. If you are a gravel rider, or a cyclist who trains a lot on loose, soft or mixed terrain, you will likely favor pressures in the 30-32 psi range with a high level of confidence and ultimate safe speeds. On race day as the terrain is worn in by previous races, you will likely drop it down, especially on courses with off-camber matted grass or soft corners, with a little wet dirt. Either way, have fun and ride fast!