Have you lost the ability to smoothly select 5th or 6th gear in your GR Yaris or Corolla? It’s likely the soft and fragile OEM hub has cracked. We’ve spent the last year testing solutions to this problem.

Our revised hub is made out of an SCM415 case hardened steel (58-62HRc). The case hardening extends to the webbing and keyway area, as well as the inner and outer splines, unlike the OEM unit which is only induction hardened on the inner splines. Aside from the material improvement, we have improved and adjusted radii around the keyway and oil slots, all while keeping the overall design similar to OEM so that it works with the standard components such as keys and the sliding sleeve.

But revising the hub is not enough – we found the hardened hub was causing premature OEM synchro failure, as the synchro shoulder was wearing out on the hard hub. Our solution, which is unique in the market, is custom chromoly synchro rings that are significantly harder than the brass OEM units. An added bonus is that the chromoly rings have an improved friction surface with moly coating, so shifting is better, too.

When you purchase this set, you get a hardened hub, and 2 chromoly synchroniser rings.

This is THE solution to the 5th/6th gear lock out issue for the GR Yaris and Corolla.

We have a video that explains some of the details of this product that you can view on youtube here.