We loaded all the quads on the trailer and were going out on a Rally that was a little ways from home...when we turned on the quest the speedometer was way off!!! it added about 600 miles to the speedometer! and it is still like that now! We think its because on the way to the rally it was bumby dirt roads so we think that might be the probleme! If you have ever had this before or heard about this let me know!