Originally Posted by donatelli
Wanna to reactive my old RC car - HPI Pro 4. Wonder if there is any chance to change the rear ball diff to gear diff?
Much thanks for all your advice!
If you could find a current car with the same (or at least close) rear bulkhead spacing as your Pro 4, you could just use its gear diff and shim it to fit. There's also the chance that there's an older Nitro car with a gear diff that would work better, as gear diffs in electric TC are still a fairly new thing. Be mindful of the tooth count on the pulley, though, as if you don't get the same size as you had, or at least change the front to compensate, you could have some over or under drive.