When I got my MINI, I was concerned that the speedo would be way off because of the 235/35/19" tires, so I had a friend who has access to a radar gun check my car... At 55 mph on the radar, the speedo registers the exact same, 66 mph... So, the taller than stock 19" tires hit the sweet spot on the speedo calibration... Who'd have thunk...

 

On my first trip home with MCCs at 120 I was being passed by everyone. Normally at 120 I am seldom passsed and never receive a ticket as the limit is 110. When I checked the digital readout I was only doing 114. I'm not sure if digital is off as well. The difference is porportional and at 50 there is little difference.

 

My speedo reads 3-4 MPH fast at 60 with 195/50/16 wheels and less than 2 mph fast with my 18" summer wheels. Minis have several different tire packages. I'm guessing they have 1 speedo for all the mins so they calibrate it to be close and work with all wheel options.

 

Mine is right on in mine. it reads the same as the Garman. They may be able to reset the tire size at the dealer since there are so many tire combo's