speedometer problems
 

Hello all, I am new to the corvette world. i just recently got my first, a 1984. I love driving this car, it is a hoot! I have noticed that the speedometer is off. at 30mph my gps says 25, at 60 mph my gps says 50. my first question is and may be silly, but could tire size make that much difference, as my car does not have the tires that were spec for it. was just wondering before I moved on to other reasons. any help would be great thanks.mark

no it may be just a faulty speed meter problem that all