Paratrooper34

Hi All,

I am looking to remove my stock 17" wheels and put on a different set. I found a nice set of 18" wheels and am wondering what effect a bigger size wheel and tire combo will have on the car. Can I just put them on and go or will some kind of reprogramming be necessary? If something needs to be reprogrammed, can I do it with a tuner that I am getting?

cruisin5268d

The wheel size doesn't matter, it's the overall height of the wheel+tire together. If you maintain that same height, then no reprogram needed for the speedo to be accurate.

jpplaw

Here's a rule of thumb - not entirely accurate but - multiply the width of the rear tire (i.e., 255) by the sidewall aspect ratio (i.e., .45). You want the result to be right around 114 or so, then you won't need to reprogram anything with the speedo.
For example - 255 x .45 = 114.75, ok; 285 x .40 = 114, ok

Paratrooper34

Very interesting! Thanks!!!

Nuke

Unless you own a handheld tuner, you can't adjust for changes in tire O.D.. If you go from 17" to 18", then you simply need to choose a tire with an equivalent O.D. as the factory tire. Unfortunately, you'll end up with a lower profile tire (a.k.a. less sidewall).