I have a very heavy magnetic base with arms on it that ajust, attached to one arm is a 1 inch gauge, in thou,s. The whole thing sits on the floor, I simply aline the guage to the rim of the wheel first, spin the wheel, once thats in tolerance, check the sprocket as well. Piece of cake. the whole thing cost me 24 bucks at a local tool shop. sorry can't post pics. ( yet )