Yes and i learned the hard way. I had a 95 v6 with 15 inch wheels. I put on a set of 17 inch GT rims from a 95 GT. Well i was going 61 i thought in a 55 and the officer said i was going 65. This is when i figured out that the speedo was off and other confirmed this would do it. I dont know how u correct it on the newer stangs, probably with a reflash of the computer i would say but dont know for sure.
The tuners have adjustable parameters for tire up sizes and gear changes. I just did mine for the 4.10's. Was reading 80mph when actual speed was 60mph. I read the tire change is minimal though. You can play w/ this. http://www.miata.net/garage/tirecalc.html
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, builds, modifications, reviews, engine swaps, classifieds, troubleshooting, maintenance, and more!