[ahgil]

Hi Guys,

I saw many post mentioning about square setup and talk about the variance for front and rear wheels from factory is 0.4% and if we are doing any wheel change or tyre change. As long as it stay within 1% the X drive should be fine..... well i still cannot figure out how to calculate the math.

If i play to do square setup. 20x 10.5 front and back. with tyre size 285/30/20 front and back. Does it mean the variance will be 0% and i am safe, and i assume the offset does not affect the variance

[blackops23]

Originally Posted by ahgil

Hi Guys,

I saw many post mentioning about square setup and talk about the variance for front and rear wheels from factory is 0.4% and if we are doing any wheel change or tyre change. As long as it stay within 1% the X drive should be fine..... well i still cannot figure out how to calculate the math.

If i play to do square setup. 20x 10.5 front and back. with tyre size 285/30/20 front and back. Does it mean the variance will be 0% and i am safe, and i assume the offset does not affect the variance

You are correct 285/30/20 is 0% variance. There is a helpful tool here to check the variance:

https://www.calculator.net/tire-size-calculator.html

You will have rubbing in the front with this set up and severity of rubbing on the inner fender "fins" depends on your suspension set-up and spacer use. I currently run this setup on my car with 12mm front and 15mm rear spacers. The rubbing at full lock is not present after removing fins and replacing with wheel arch aluminum metal plate. Install here:

https://g80.bimmerpost.com/forums/sh....php?t=2073263

[ahgil]

Oh Thank you so much for that calculator, i think that is what i need to bookmark. yea i know it will rub so if i do decide to go this setup, i will cut out those fin to avoid rubbing. Just find it super headache to run stagger width and deciding on the tyres. Its like a puzzle game haha

[BIGW0RM]

Heres another offset and circumference calculator for wheels and tires.

https://www.willtheyfit.com/

[VELGEN WHEELS]

We’ve done a lot of them with a 285-30 front and a 295-30 rear and have never had a hiccup with it at all. Dropping it to the 285-30 square will be no different you’ll be 10000% fine

[mjponti]

Originally Posted by VELGEN WHEELS

We’ve done a lot of them with a 285-30 front and a 295-30 rear and have never had a hiccup with it at all. Dropping it to the 285-30 square will be no different you’ll be 10000% fine

Any modification needed on MPerformance HAS? I'm looking to do this is exact setup - 285/30 front and 295/30 rear.

[VELGEN WHEELS]

Originally Posted by mjponti

Any modification needed on MPerformance HAS? I'm looking to do this is exact setup - 285/30 front and 295/30 rear.

You might need to push in the vent up front on the fender liner with a heat gun or buy liner replacement if it really bothers you but you might get a very very minor rub on full lock turn reverse. It rubs out eventually we usually heat gun it and push it in.