Quote:
Originally Posted by MattR
Wow, great communication from the vendor, but too bad on the part failure. Is it caused by torque on the wheel or by vibration? No chance you can run with the stock wheel correct?
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The manufacturer of the part is claiming that the failures are all due to over-torquing the nut that holds it to the steering column. Now I know I used a torque wrench when I installed mine... but I don't remember the torque spec I used. The hub adapter manufacturer says 25 ftlbs max, the factory spec is 36 ftlbs. I may have used the factory spec because I don't remember even seeing a spec in the adapter packaging/instructions. My guess though is that the break occurs if you have to remove and reinstall the adapter. I installed mine, then had to take it off in order to fix a bad relay in the steering column. In order to break the nut loose to remove the hub adapter, I had to install the steering wheel and hold it while breaking the nut loose w/ a breaker bar. It took kind of a bunch of torque to get it to come loose... I'm willing to bet that's when the spline fractured, then the crack widened with use.
Either way, MiataRoadster is revising what they sell when it comes to those adapters... they're going to be including explicit warning not to over-torque the nut, a different nut w/ a washer or flange to distribute the force of the nut, and a pressed on steel ring around the back of the adapter to prevent any possibility of a fracture. The problem is, those kits aren't going to be ready in time for the track day.
So, Bill at MiataRoadster is sending me a different version of the adapter (the 20mm shorter one) that's billet instead of cast aluminum. It's designed to be more compact for use with a wheel quick-release without changing the location of the wheel... but since I'm so tall, I need the wheel to be pretty far away from the dash (which is why I purchased the longer 3" adapter in the 1st place). So Bill's also selling me a 30mm spacer for use with the shorter hub. I should net a +10mm longer adapter which should fit well for me in the car. And it should be in the mail today, so I might even have it before this weekend.