In light of recurring mechanical failures of rear hubs on Spec Miata cars, NASA realized the need to update the rulebook to allow for the use of rear hubs that are non-OEM.
NASA series leadership determined that the use of non-OEM hubs presents no performance advantage, and that the use of more robust aftermarket components is a plus for safety. The NASA Spec Miata rules have been updated with an added section, which is cited below:
“15.16 Non-OEM Rear hubs are permitted provided they retain the OEM rear wheel bearing. OEM track width must not be altered. Hub flange may be increased to a maximum thickness of 12.5mm. Hub must be a single-piece ferrous material.”
The bearings are still required to be OEM, and those sold through Mazda Motorsports are the best available. OEM MAZDA rear hubs (Part No. 0000-04-5HUB-RR) are sufficient for the needs of the community, and the failures commonly seen across the country are frequently due to age and mileage, crash damage, or lower-quality reproduction parts. However, racers now can elect to move to a stronger design to lengthen the safe service cycle of their rear hubs versus those built to factory dimensions.
“Hubs have been a conversation point within the greater Miata community for several years,” said NASA Spec Miata National Director Jim Tramontano. “Our leadership has been keeping a close eye on the state of rear hubs as they relate to Spec Miata racing within NASA. As racers, we continue to find new ways to make our cars faster. It has become clear that the aging factory-spec hubs have an increasingly difficult job to do. Due to the often-catastrophic nature of rear hub failures, we felt it was in the best interest of our racers to amend the rules and allow aftermarket hubs designed specifically to live up to the rigors of modern racing and tire technology.”
