Converting BMW Wheel Bolt Pattern to GM

BBShark

Garage Monkey
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The track width on my car is not stock (a little wider). So, that sort of complicated my selection of wheels. What I found is that lots of BMW wheels had the correct offset AND would clear big calipers.

There is a catch. Bolt pattern for BMW wheel is 120mm (4.724 in.) and GM is 4.75. 4.750-4.724=.026. On the radius, the pattern is .013 smaller. If I used as is, when the lug nuts were tightened, there would be a significant bending put on the studs. Not good.

The fix for this was to recut the tapered seats in the wheels. I built a fixture that has a carbide burr set at the GM radius. the other for posts on the fixture can be rotated 180 degrees to seat in the BMW or GM taper. When you cut one seat, the fixture is removed and the post for that newly cut seat is rotated to the GM pattern. Do five times.

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Hard to beat the quality of oem wheels. Sounds like a good fix. Some guys with mustangs convert 4 lug to 5 lug for the sleeper look ( I believe there is a cover over the lugs). But that involves filling the old holes with press fit alum.

How do they look? Style wise.
 
They are aftermarket BMW wheels. There are tons of different styles. I picked these because they have a traditional 5 spoke design that I thought would look good on an old car.

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Well I finally got around to doing a wheel. Went pretty easy.

I've been slacking on car work. Lots of stuff to do at the house with fall in Ohio.
 
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