Challenge Grifo Open Tubular Tire
The Grifo owes its success to a host of seemingly singular contributions, but ultimately, it all comes down the tread pattern. Challenge bestowed a pattern, that, at first glance, appears low in profile — and that's because it is. The pattern design doesn't require the extra weight of bulky, tall knobs. Instead, the evident knob shape provides ample grip in terrible conditions while minimizing the associated rolling-resistance over harder stuff. The highest point of the pattern lies in the middle of the tire, while moving outward, the knobbies gradually take on a svelte shape to provide traction in corners. However, the Grifo's tread pattern is intended to be mounted in either direction. Should you require heavy traction, say in hearty mud conditions, Challenge recommends that you mount the tire with the tread orientation facing backward. For "normal" race conditions, mount with the tread rolling forward.
The Grifo is also constructed from a highly puncture-resistant and lightweight Super Poly casing for durability. The open tubular clincher construction uses the same hand-made construction techniques and materials as Challenge's tubulars. The only difference is that instead of being sewn, beads are actually formed by folding the casing around Aramid fibers. This fiber prevents rolling-off in corners, and adds to the cumulative strength of the tire.
The Challenge Grifo 33 Cross Tire - Clincher is available as a 700c x 33mm open tubular tire and in the color Black/tan. Each tire weighs in around 340g without tubes.