Originally posted by robk
Hinge pins are 2.5mm per HPI manual. 254mm = 1 in. TC3/Losi pins are 3/32" I think, so they are .093 ". Close to 2.5mm, or .098 " David probably has the best idea, use TC3 axles with Hpi bones. Just need to ream out the hinge pin hole on the hubs.
the bones on the TC3 are excactly the same as the Pro4..50mm