Necessity of 0.5mm Thick Hub Rings?

Joined
Mar 16, 2009
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2,159
Location
Southeast Michigan
I have an aftermarket set of wheels on my 2013 BMW 335i. They came with 72.6mm ID to 73.1mm OD hub centric rings. During a tire rotation today, I discovered that one of the hub rings had pretty much disintegrated. Given that they are only 0.5mm thick, how necessary are they? They are so thin and fragile.
 
If your vehicle is hub centric, the weight is intended to be supported by the hub, not the lug nuts. I would replace it.

Why / how did it disintegrate - salt / corrosion or? I realize 0.5mm - ie about 0.020 inches - is paper thin, but really it shouldn't fail - its pretty much just a shim.
 
Yeah, about 3 years of salt and corrosion seemed to do the one in.

IMG_2159.jpg
 
f your vehicle is hub centric, the weight is intended to be supported by the hub, not the lug nuts.
Ah ..... Mmmmm ...... Not exactly

Hub centric means centered by the hub - lug centric means centered by the lugs! It does not mean "supported"!

What prevents the wheel from separating from the hub is the clamping force generated by the studs (lugs) and the lug nuts. That's why there is a torque specification. That torque preloads the wheel and in turn, that generates the friction necessary to prevent the wheel from moving. Not enough torque and the wheel moves relative to the hub and that loosens the lug nuts.
 
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