My Garmin's readings have always correlated perfectly with the speedometer's readings, if anything my top speed was higher I think....as you have to maintain a top speed for X amount of time before the Garmin registers that speed.

I had to replace my fronts a couple of weeks ago....the car was out of alignment from the factory & the fronts were really worn on the outer treads + one had a slipped belt....as an emergency replacement was called for I went with a Cooper All Season tire on the front.....I'm happy with them....but (at least not yet), Cooper doesn't make that tire in 255 /35/19 for the rear.

Anyone have the General Exclaim ? Tire Rack specs say they have a tread pattern / depth etc that meets an All Season requirement ....BUT (maybe due to temp-compound) they don't recommend they be used as such??????