bgood

Does anyone here know if the C7 speedometer auto calibrates based on GPS?

One of my other vehicles does this and it is a nice feature when changing wheels or replacing worn tires with new ones.

BRCC

GPS is point to point, when driving up and down hills GPS measures point to point and not actually the speed on the road. Don't see how that would be a accurate mph reading, unless it only calibrates on flat roads. How does it know??

Cruiter

Try to picture square grids beaming down on you from space (they actually are). The device calibrates the speed between several squares to average out. My Lexus has this feature, usually you use it after changing tires or if your tires are about 50% or more worn. It works too. I've noticed after doing it, the GPS speed shown on my Escort Max (with smart cord) measures up to the speedo better.