It's time to replace the tires on my 2004 Mountaineer and I thought it would be a good time to change the stock 16" wheels to a set of OEM 17" wheels to make it look a little better (assuming I can find a set for a reasonable price). What will I have to do after I change to the 17" wheels to the vehicle? I guess the speedometer will not be correct.

 

I think your speedo will be the same as long as your overall tire diameter is the same.. if the overall tire diameter is bigger then it will be off

 

If you go from say a 265/75/16 to a 265/75/17 the speedometer error will be aboout 1mph at 25mph and about 3mph at 65mph