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      06-17-2012, 09:59 AM   #1
Brigadier General
Fraggy's Avatar

Drives: 2016 M3
Join Date: Jun 2005
Location: San Diego

iTrader: (11)

Wheel and tire advice please

I am considering purchasing a CPO 09 335 sedan. The used car manager decided to put the sport line wheels from an F 30 on to that car using the original tires. The tire size is 225/45/18 versus the cars original 225/40/18.

I used the Tire Rack calculator and basically what it told me is that the new overall diameter would be nearly 1 inch larger. The calculator then went onto say that at 60 mph The speedometer would be reading 62 mph. I'm a bit confused by this, as my tiny brain leads me to believe that a larger overall tire, at 60 miles an hour would be turning more slowly than the smaller tire and showing a slower reading at 60 mph.

Please help me understand this, as I'm planning to look at the vehicle today and possibly purchase.
2016 Alpine White M3