How will 18inch rims effect my top speed and speedometer.

[m3f_hammerk]

Just bought 18x8.5's all around and i was wondering how it will change my top speed. Also will it throw off the speedometer. Thanks for any info.

[m3f_imran_306_cab]

Try this .....



http://www.miata.net/garage/tirecalc.html

[m3f_DSK M3/4_7bd32f4682]

if you do the appropriate plus one sizing, the effect should be minimal. contact a good tire dealer or tirerack and they should be able to set you up.