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KEEP M3POST ALIVE BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER LINK! |
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07-23-2009, 07:37 AM | #23 | |
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This is done to cut manufacturing costs for the wheel company, by making their standard center bore for the vehicle with the largest wheel hub. That means one car will have a direct hubcentric fitment (perfect), while all the other cars with that same bolt pattern will be forced to use hubcentric rings, in order to close that small gap. If you don't do this, there is no way to properly center the wheel on the cars hub, creating a shaking sensation at speed. Just another way we get screwed in the grand scheme of things...
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07-23-2009, 01:39 PM | #24 |
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Thank you for your answers folks, but remember I have STOCK 19s. The rear hubcentric 'rings' don't fit my wheels like a glove, meaning there's a very small gap since I can easily push the wheel in and out without having to 'shove' it in place. Yes, the wheel is beveled to make it easier to install the wheel, but there's minute play when fully mounted with no lug bolts inserted. In addition I had to sand the rusted 'rings' a little to remove all that crap, but shouldn't make a difference with 400 grit sandpaper. I honestly don't think that the 'rings' are an issue just at 60-65 mph; if there was a wheel 'bouncing' problem it'd increase with speed, correct?
My guess is probably balancing, but who knows. Wonder if BMW would pay to check that. Thanks. Last edited by JCtx; 07-24-2009 at 01:29 PM.. |
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07-24-2009, 01:32 PM | #26 |
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Is it also intermittent, and between 60 and 65 mph? Wonder if it's wheel/tire or suspension/steering related. Mine is not bad enough to do anything about it now, but will be watching it. Thanks for your comment.
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07-24-2009, 03:14 PM | #27 | |
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If that is ruled out as the root cause, then it's very likely that you have a brake rotor problem. (embedded brake pad deposits) The reason it only shows up at certain speeds, is due the centrifugal force involved in spinning a large round object like a wheel, brake disc, or tire. There is a point where the revolutions per minute (rpms) are just right to re-create the shaking (vibration) which results in a out of balance condition. You'd think the shaking would be consistent with predictable linear progression...but it's not. It's very sporadic due to the harmonic balancing issues mentioned above. It only takes a small shift in the overall weight distribution of a wheel, tire or brake disc to cause this shaking problem. (just a few grams in fact) This has happened to me more times than I care to remember, because I'm always changing out the tire and wheel combos on my cars. (I get bored with the same look) +1 to the guy that said it's annoying.
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