should be a neat fit into the middle of the disc, and have a little tab on it so that it can be driven by the cut outs on the hub(you'll know what i mean when you pull the old speedo drive off... the the only thing you are changing is the speedo drive plate, not the gear box, so the gearing to the speeod isnt changed...all a bolt on affair and away you go, well for the wheel anyway...peace