Need some HELP from the Gurus...
07-26-2018, 11:06 AM
#26
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W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Yes, the 10" rim itself will be ~12.5mm wider than a 9.5" rim - but it's not the rim, it's the tire that rubs. 
You need the wider rims to properly support the tire carcass - it has nothing to do with the tire rubbing. To deal with the rubbing, you need to correct the wheel offset. By moving the offset from your ET 45 BBSs to ET 50 rims, you are moving the outer edge of the tire (that rubs on the fender) inwards by 5 mm. The same tire mounted on a 9.5" wide rim and a 10" wide rim with the same offsets will rub just the same (I am neglecting the minuscule width change near the contact patch due to the tire shape change resulting from the change in rim width).
You need the wider rims to properly support the tire carcass - it has nothing to do with the tire rubbing. To deal with the rubbing, you need to correct the wheel offset. By moving the offset from your ET 45 BBSs to ET 50 rims, you are moving the outer edge of the tire (that rubs on the fender) inwards by 5 mm. The same tire mounted on a 9.5" wide rim and a 10" wide rim with the same offsets will rub just the same (I am neglecting the minuscule width change near the contact patch due to the tire shape change resulting from the change in rim width).
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07-26-2018, 11:27 AM
#27
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2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
+1
The same size tire will stretch out more on a wider rim, reducing the shoulder bulge at the top that you currently have by mounting it on too narrow a rim. This alone will round out the tire profile and reduce the possibility of rubbing.
The same size tire will stretch out more on a wider rim, reducing the shoulder bulge at the top that you currently have by mounting it on too narrow a rim. This alone will round out the tire profile and reduce the possibility of rubbing.
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07-26-2018, 01:16 PM
#28
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2015 Mercedes C63 amg 507
Brembo from FCPEURO...
Thanks for all the help... should have asked the experts first before buying the wheels instead of searching the forums...
At least the brakes are set for the weekend at VIR... new Brembo front rotors and a 2 liter Castrol SRF flush...
