Chris switched from a seat rail with discrete detent positions to a sliding clamp that allows infinite adjustability. It had to be carved out of billet stock to match the shape of the main tube, which he claims did not take as long as you would expect.

(This could have something to do with the borderline obscene assortment of power tools he is alleged to have available both at work and in his basement!)

The clamp also carries two plastic idler wheels on one axle to produce an X-shaped chain line. The frame has clearance for knobby tires, partly with an eye toward next year's ice races.