My E320 4MATIC has 16 x 7 1/2 rims. Can I change to 17" rims without upseting the computer? How about the width, does that change anything?

 

changing the wheel size does little. it's the overall circumference which impacts readout.

use this ----> http://www.miata.net/garage/tirecalc.html

to help you decide size and keep within reason.

when you change to larger wheel size you begin to limit the flex/cushion that the taller sidewalls provides with the smaller wheels. price of larger tire begins to go up. wheel weight also climbs unless you're into big money and forged rims.

p.s. forgot to answer your question: yes, you can easily change from 16 to 17 w/o affecting speedo etc. just use the above calc and plug in your current tire size. juggle the newer size for yoru 17 rims so that it is well within single digit differential. the wheel width will not affect speedo....but you need to keep an eye out so that nothing rubs. if you keep within reasonable widths....say, no more than 8 to 8.5" you should be safe but again, check to see what others have done on the MB boards.

do NOT stagger the sizes....given that you have 4matic. may look cool, but may potentially trash your gear box

 

Thanks Raymond for your very informative reply.