My speedometer according to a couple of GPSs is reading 3 mph higher than I am actually going.

Anyone else have the same issue? Can the dealer adjust?

 

My speedo is about 3 km/h (about 2 mph) optimistic at highway speeds according to my GPS. That is an error rate of about a 2-3%. OTOH, the odometer is almost dead on.

I'm not complaining; most of the motorcycles and motor scooters I've owned have had speedometers that are 10% optimistic.

 

A few days ago I was driving with my GPS in car. I noticed the car speed on the HUD was often 0-2 MPH faster than what the GPS showed. Close enough for me. I noticed that the speed needle and the HUD were sometimes about 1 MPH off. Not sure how often the HUD actually refreshes the speed shown, same for GPS so that could account for some of the differences. This was done without cruse control, so my speed was mostly was not steady.