Steering shaft / wheel interface diameter
I have a very strange problem while trying to convert my '92 Miata from Airbag Wheel to Nardi, using the HKB OR-205 Boss kit:
Shaft and wheel meet in two points - a spline interface and a centering cone (see attached).
The cone-diameter is root-cause of my issue. On the hub, it is to wide, making the hub slip over the shaft too far (blocking the turn-light-reset plastik part and making the shaft cut into the spline of the hub). As a result, the wheel is not centering itself anymore and is very hard to turn.
In the very front of the hub I measure 17.5 mm (be careful not to measure the flange or too far into the cone). On the original wheel it is around 16.7 mm.
Now my dealer of the hubs says, all his OR-205, which are designated for NA miatas, have this diameter and he only found my diameter on hubs designated for NB models. His theory is, that I have a NB steering column in my NA.
HOWEVER, my steering wheel is completely stock NA and features the small (supposedly NB) diameter combined with the NA signal-reset hole pattern. I am super confused! I guess mazda made a custom diameter for my personal NA on shaft and wheel.
Does someone else have a pre-'94 NA-Airbag-wheel or a NA-conversion-hub lying around and can confirm / deny my measurements?
You would help me quite a lot!