It is still in the build stage. John Deere T30c (30cc), a Wal-Mart bike (Next Shocker, with a BMX style handlebar, by me), a road tire in the back, and a mini bike wheel. I took the wheel, ground the weld in the center that holds on the rim halves, and knocked off the halves. That left me with a greaseable, ball bearinged, 1 5/8" diameter shaft 6" long. The weld-a-pulleys that Farm & Fleet sells, made by Weasler, also fit sprockets. The W series pullies and sprockets have an inside diameter of 1 5/8", go figure. I'm using a 19t #40 sprocket on the roller, and an 11t sprocket on the engine. Just ordered, not received. That gives a drive ratio of 1.72:1. My tire to roller ratio is 16:1. Even if my engine doesn't pull great, it can be modified, or just use it as an assist, as I like to haul when I ride my bike pedal power. I figure I can leave the #40 chain a little loose, and not worry about it falling off, as I don't want to burn the bushing in my trimmer clutch. I'll probably install a bearing on the very end of the clutch to help preserve the bushing. Will post pics when the build commences.