BMW M3 Forum (E90 E92) - View Single Post - Bbs FI 18”

Richbot · 05-05-2019, 10:18 AM

That’s ~1” smaller diameter than GTS with same widths. ~24.8” vs ~25.9” diameter. Ground clearance (and center of gravity) will be lowered about half an inch so keep that in mind if scraping on stuff is a concern

I think handling wise it’d work fine especially with the Yokohama which runs very wide. The gearing change from the 285/30-18 is significant so keep that in mind too. You’ll be shifting more and earlier than a stockish size tire, and running higher rpm on the highway in top gear at the same actual road speed. Indicated road speed inside the car will be off by a couple extra mph as well. None of that is that big of a deal.

Truly analogous to GTS size would be 255/40-18 and 285/35-18

05-05-2019, 10:18 AM	#2
Richbot Major General 2760 Rep 5,483 Posts Drives: Jerez Black E90 Join Date: Sep 2007 Location: STL iTrader: (5)	That’s ~1” smaller diameter than GTS with same widths. ~24.8” vs ~25.9” diameter. Ground clearance (and center of gravity) will be lowered about half an inch so keep that in mind if scraping on stuff is a concern I think handling wise it’d work fine especially with the Yokohama which runs very wide. The gearing change from the 285/30-18 is significant so keep that in mind too. You’ll be shifting more and earlier than a stockish size tire, and running higher rpm on the highway in top gear at the same actual road speed. Indicated road speed inside the car will be off by a couple extra mph as well. None of that is that big of a deal. Truly analogous to GTS size would be 255/40-18 and 285/35-18 __________________ Last edited by Richbot; 05-05-2019 at 10:23 AM..
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