Hi, I just had my factory 245/75/16 tires switched with 265/75/16 tires. I was just wondering if this really throws off the speedometer, odometer and or tachometer and if so how much? thanx

Your speedo will be 3.9% low. Odometer will also be off by 3.9%. Tach will not change since that is engine speed.

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

//2000CAYukon

you can get a dealer to recalibrate the spedo with a tech 2. some aftermarket programers can do the same thing

I have 255/85/16's on my truck and the dealer said they could only recalibrate for them if they were an option on the truck.