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Does BMW stamp the bore size on the wheels?

1094 Views 3 Replies 4 Participants Last post by  edjack
I'm sick of trying rims on! lol
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No, but you could just carry a cheap micrometer.
+1No--I use a hub rings for o.d. 72.56 & 74.1 to check hub bore-cheap and easy

Sent from my SGH-T959 using Bimmer App
The E39 has a unique hub size, 74.1 mm. cdawg246 has a great idea.

Yep, Albo, too, Harbor Freight Tools has a very nice electronic caliper for about $10. It does SAE and metric measurements. You can even zero it at any setting within its range. Even comes with a spare cell! Clever, those Chinese.

BTW, if they are genuine BMW wheels, the Roundel and the BMW part number will both be present, either on the inside, or outside.

Wheel offset is an important measurement, and any wheel you install should have an offset close to the originals. Ignore negative and positive offset; there is confusion about the definition.

Wheel Offset

Wheel offset is part of the suspension design. If you mount wheels that have a different offset than the stock wheels, it will upset the suspension, perhaps not enough that you would notice it. The worst will be premature wheel bearing failure, if the offset varies much from stock. You may also suffer some loss of steering precision.

Best to stay with stock offset. The best way to do that is via BMW take-offs from a newer model that will fit your car.

Measure offset like this:

Lay the wheel (or wheel and tire) face down on a flat surface. Measure the distance from that surface to the back of the wheel (lay a straightedge across the back of the wheel.

Measure the distance from the back of the wheel to the mounting surface. Subtract this value from one half of the above measurement. If negative, the wheel has negative offset (the wheel, when mounted, is "pushed" towards the center of the car.

If positive, the wheel is "pushed" out away from the center of the car.

Do not accept measurements like "backspacing". Always measure the wheels yourself.

BTW, chromed wheels look great for a few years, until the chrome starts pitting and flaking off. Then you will be sorry that you did it.

BTW2, if you do buy aftermarket wheels, make sure they are "hub-centric", which means that the wheel fits onto the hub of the rotor, and is thus centered, as opposed to being centered on the bolts.

Not all BMW models have the same size hub. See this site: http://www.gruppeb.com/BMWwheels/fitments/
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