I've looked around the forums and haven't found an answer, so I'm throwing out my question as a new thread

Does anyone know how to correct for the speedometer error in a Mini (mine's an R60) resulting from changing the rolling diameter with increasing wheel & tire sizes? On my Mustang it was just finding the right performance programmer and plugging it into the OBD data port.

Thanks!

 

You'll find a calculator here. Lots of good stuff on the home page. The second link has what you need.

http://www.csgnetwork.com/automotiveconverters.html

http://www.csgnetwork.com/tireinfo4calc.html

 

I know that you can code out the over estimation on the digital speedometer with software and cable. I have never seen a discussion on calibration for tire sizing. There is a coding thread here somewhere in second generation cars or Countryman.

 

Thanks! One of my friends suggested that the NCS Pro software might be able to tell the ECU/PCU that the tire circumference is larger and correct the speedometer error created by up-sizing the tires. I know its sacrilege on this site, but I need to soften the ride on my S model (with sport suspension) for the sake of my back.

 

it is not worth the trouble.

i have had 3 sizes of tires on my 12 all4.

stock 225/45R18, OD 25.9 inches, speedo fast by 1.9 mph

oversize 225/50R18, OD 26.9 inches, speedo spot on

big oversize winter tires, 205/70R16, OD 27.3 inches, speedo slow by 0.9 mph