BBS 16x71/2 hub size

[Jesse]

Hi,

New guy here. I recently purchased a 1987 635Csi for my son and it came with BBS rims. I have a shimmy at higher speeds and realize I need hubcentric rings. I know the hub size for the car is 72.56mm, but don't know the hub size of the rim. Does anyone know? I don't have a micrometer to measure it.

Thanks!!!

[tschultz]

Likely the 74.2mm from the E39 as that's the only other major BMW hub size.

I didn't know they made a 7 1/2" width wheel for the E39 though...

[hornhospital]

Are there spacers behind the wheels? That hub looks to be abnormally deep in the wheel hub.

And the E39 wheels have a 74.1 hub bore, not 74.2. You need 72.56 to 74.1 hubcentric rings.

[Jesse]

I guess this are E39 wheels. Yes I'm looking for the aluminum ring that goes behind the wheel and centers it on the hub. Just wasn't sure on the size. http://www.discounttiredirect.com/direc ... sWheels.do

[mojocoggo]

Those aren't any sort of E39 wheel. However, lots of cars came with wheels, so those could be from a GM car with a 5x120.7mm bolt pattern and a larger hub bore.

Those aren't stock lug bolts, so someone at some point made a decision to change something. Just take all the lug bolts out, and see if you can slide the wheel around on the hub. If it's the right size, you'll feel absolutely no movement. If there's even a little play, chances are the wheel hub bore is too large.

There's also a 90% chance you need new upper control arms.

[tschultz]

Are you sure they aren't the E28 M5 wheels?

These are from mine... just with caps:

[Jesse]

They do look alike. I'm going to pull one off this weekend and measure it. Had to replace the clutch and master cylinder this weekend. That was a PITA.

[TN_M6]

I've searched and study wheel options at times and to the best I've learned the only 7,5x16 wheel in the cross spoke design was the M5.

If the spokes or ribs touch the outer lip rather than end flush with the inner face it's almost positively an M5 wheel.

[Jesse]

So it ended up being a combination of the tires and a bent rim. The car had been sitting for a long time. Replaced the tires and put the bent rim in the back for now. Didn't need the rings. Thanks for all your responses!