my new axle came in today and i just wanted to know what size the axle nut is? i thought it was supposed to be 36mm so i bought a 36mm socket but it isnt fitting the nut that came on the new axle. also, is this nut supposed to replace the new one because it has something at the end of the nut that doesnt let it screw down past a certain point. or do you just reuse the old one?