Steering Wheel Bolt Patterns - Grant, Momo, Nardi
Here is another in the EZ Read series of guids. Trying to make your own hub adapter? Trying to figure out which steering wheel fits what adatper, well look now further (well you could I guess). Here is a few LARGE images which outline each of the more common steering wheel bolt pattern. Wheels included are -
Here are steering wheel information for the following brands
Grant Adapter 3 Bolt and 6 Bolt
Nardi and Personal with 6 Bolt 74mm PCD
Momo, Sparco, ISOTTA and NRG with 6 Bolt 70mm PCD
Mountney, Lecarra, Moto-Lita and Springalex (9 bolt 4" PCD)
Many of these share the same patterns so look below for more info on which ones does. Once tricky part is horn buttons. Some wheels the horn is secured in the steering wheel itself. In others (like Momo) they rely on the steering wheel adapter for it to snap into, or a add on plate that sandwiches between the steering wheel and the adapter. Most companies don't give out much information either, parts and adapters to different wheel companies and hubs are available from many sources such as Amazon and EBay.
Last note is that it's unclear what type of bolt are used for some wheels. For example any wheel with countersunk bolt holes should use the proper metric or imperial (USA mostly) bolt style. Metric countersink bolts are 90 degree angled and imperial style are 82 degree which can cause some issues. Again, I have not seen any company that defines what is what on their wheels. Some adapters also give metric hardware, some imperial. I have used both but not really sure which is right or specific for a brand of wheel. I sent a request to Momo, will report if I get an answer. Also if using imported spaces it might be a good idea to check the quality of the fasteners. I have got some that do not look that great and worth a few extra bucks picking up some high quality from McMaster-Car, they have them in stainless, and black, Metric and standard, and in many different lengths and head styles.
Most (not all) fall into one of these categories. I'm currently missing the Grant style wheel and one other, but will add them shortly. If you need more info on one that is not listed, send me a note and I'll add it in for future reference!
Scroll on down for the EZ Read Steering wheel hub patterns