Quote:
Originally Posted by vladniko86
Whats the big deal with the difference in diameter? I downgraded to 245/40/18 in the front, but you know those low profile tires are more expensive that's why I got 40 series
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A 245/40/18 is 4.5% larger than the OEM diameter. A difference of +/- 3% or less is what is generally accepted as a good idea. I know there are alot of guys running 245/40/18s. I think it's alright, but would not go larger.
The diameter difference will change the accuracy of the speedometer and the odometer, can cause rubbing, and IMO adds unnecessary weight.
The largest diameter tire I would suggest is a 265/35/18. It is 2.8% larger than OEM. If you need a wider tire, a 285/30/18 is actually only 0.4% larger diameter than stock, 24.7" vs 24.6", and fits on the car easier than a 275/35/18.
A 275/40/18 is 8.5% larger in diameter than OEM and is 1.1" taller than your 245/40/18s!
I would sell the 275/40 tires and get smaller diameter ones.
Also, the profile of a tire changes with its size. A 215/45/17 and a 275/35/18 both have the same exact tire profile height of 3.8".
https://tiresize.com/calculator/
Play around with this tool. It helps see what tires will fit best.
Cheers!
