18" AMG wheels - will it throw out the fuel comp readings?

[Evo]

Can someone help with a query I have.

My C Class has 18” AMG wheels fitted on 45 profile tyres. The over circumference is larger than the original 16” wheels with 65 profile tyres, probably larger by some 1 ½ inches. Will this throw out the reading s I get from the fuel computer relating to the current and average mpg??

Thanks in advance

[YAD061]

In a word, yes

here's a calculator to help you find a closer profile

http://www.etyres.co.uk/tyre-size-calculator.htm

[Evo]

Many thanks,

The overall difference is 4.4 percent overall, not sure by how much it will affect the readings though.

Edited by Evo on Friday 15th January 21:24

[V8Maverick]

Evo, if it helps, I work in the industry and it is not recommended to deviate from the range of -2% to +1.5%. However, 16 to 18 inch conversion is more than possible. Please feel free to chuck over your original wheel and tyre size and I'll post the sizes you can go to under the rules of conversion.

It will signicantly affect your fuel reading, speedo, odo, vehicle handling and fee, etc if you choose to go for a conversion that is outside of these guidelines, but ultimately it is your choice.