W202 C class owners with 16" rims...a quick question

[mjtray]

Hi,

I currently have a 1995 C280 which is riding on 15" rims. I'm looking to upgrade to a set of 16" 8 hole Merc alloys and would like to know what profile tyres I need to fit to avoid messing up the accuracy of the speedo.....can anybody help me with this?

And lastly, and I know that this has probably been covered before, but I get real confused with all this talk about offsets However, I have read somewhere that a set of 16" 8 hole alloys off a W124 E class would fit my C Class with no problems......is this the case?

Cheers

 

[jakmeticklerpaper]

Hi
I'm a professional engineer and I have faced these tyre/wheel questions before, in relation to Mercs and other cars. I can tell you straight away that not many people can give you the answer correctly and that includes most tyre and wheel specialists. Remember that, if you screw up the tyre/wheel combination, you not only get incorrect speedo readings but you will have affected your car's entire performance, by effectively changing all your gear ratios! On cars with traction control you may also upset the wheel sensors and end up with further problems.
What you need to achieve is to change your wheel diameter and tyre profile without going away from the original wheel/tyre's rolling circumference. To do this you will need to go back to some simple schoolboy maths. Take the diameter of the original wheel plus the depth of the original tyre and work out the circumference. Then do the same with your proposed wheel/tyre combinations, using different tyre profiles, until you come up with a combination that gives the same (or very near) circumference. Bingo!

 

[GrahamC230K]

The stock 16" sport alloys fitted to the W202 C-Class are fitted with 205/55 rubber if that helps, but I guess the width of the alloys you are fitting will also affect the profile.

I think the regular sport alloys are 7J width?