At the 2018 Sea Otter Classic, we spent quite a bit of time in the Challenge Tires booth, talking fat tubulars and shedding inner tubes, and inspecting the new bikes of Helen Wyman and Molly Cameron.

We saw hints of it at Frostbike, and grabbed a quick look at NAHBS 2014 but it’s official: Challenge has added the Gravel Grinder in three forms: clincher, tubular and open tubular, giving you the ...