For 17" wheels, which is a good thickness of the tire 40 or 45, so it will maintain speedometer accuracy?

thanks

whichever is closest to stock tire/rim combo size....which i believe would be the 40's.....i am almost positives....the 45's on my car make my 16's really close to stock size. So i imagine 40's would do the same on 17's.

For the most accurate mph, 225/45/17 is closest to stock. Next is 215/45/17. If you want to see exact details, go to http://www.whalentire.com and look at tires. It will tell you the size choices recommended for 17" rims and the difference in mph based on the size you choose.

My stock wheels right now is 14" with 195/70/14 tire.

If you see too www.MachV.com there is a statement like this,

#
95+ with 14" wheels

Your car came with a 185/70R14 tire, which has a rolling diameter of 24.2 inches. You can install tires of size:

195/55R16

225/40R17

225/35R18

Wheel width should be 7, 7.5, or 8 inches
#

from this statement, we can see the most accuracy is with 40 tire for 17" wheels. but much of you using 45, thats why im very confuse.

My next wheel is become 17"x7.5, what is the best tire size for this wheels? is 215/40/17 fine?

Thanks for your help

stock 17 is 215/50/17