CAMJAG

iTrader: (34)

When I bought my car it had 18inch rims on it front and back but my questions is if I were to change them over and put the 16s back on them would it mess up the MPH, RPMs, miles, and what not? Is the cpu going to have to be recalibrated?

P Mack

iTrader: (6)

That all depends on the diameter of the tires. It's possible for 16's to have the same tire diameter if they have a taller sidewall. But if it is different, your speedo and odometer will be off by the same percentage and will need recalibrated.

CAMJAG

iTrader: (34)

Front is 275 35 18
Rear is 295 35 18

Change to 245 50 16
All the way around

Would this even out or will it be off?

Red99TA

iTrader: (11)

Not sure if the car takes speed off the front or the rear wheels but the 295's will have your speedo reading 1.9% too slow and the 275's are .2% too fast (close enough). I doubt the previous owner had the speedo recalibrated considering it would only be 1.9% off max so throwing the 245's back on would make the speedo accurate again.

P Mack

iTrader: (6)

The car takes the speed off the vehicle speed sensor on the output shaft of the tranny, so the rear wheels.

CAMJAG

iTrader: (34)

Yea I mean everytime I drive by those radars on the side of the road that reads your speed it is accurate. The car will be exzactly at 40 and thats what the radar says so it should probablly all be the same

horist

295 35 18
= 295*.35 / 25.4 = 4.06 = sidewall height

so tire height right now is 18+ 2(4.06) = 26.13"
(245*.50 / 25.4 )*2 + 16 = 24.7"

so speed will be off...