These are 5 on 4.75 2 piece drums. I have a 51 1/2 ton but somebody rolled a 53-54 3/4 front end under it. I found one drum/hub from a guy. He's the one that told me it was off a 53-54 3/4 ton. I have measured the studs. The knurl is .700, shoulder is .55 and it's 1/2-20 count. I've looked all over. The closest I can find are .685 and I don't think that will work.