[Chrisxdrive]

Hi,
On my M235i xDrive GC the original tires are 225 x 40 x 18" on 8" ET 54 rims.
I would like to change them to slightly taller tires for driving comfort.
So for tires 225 x 45 x 18" on new BMW rims 8" ET 57>
The simulation shows that I will get a Negative Scrub Radius -7.
compared to original tires and rims.
A question for those who know the secrets of BMW suspension settings .
Is this difference [ -7 ] within the tolerance limits of the suspension ( Scrub Radius ) settings .
What is the factory value of Scrub Radius ?????
If not, does this difference affect ride quality.
I can't find technical exact suspension data for the M235i xDrive GC anywhere.
I will be grateful for your help ....

[schnell325]

What simulator are you using for your calculations?

[Chrisxdrive]

I received a message that you replied to my post
But your answer is empty
There is no text...
Chris

[Chrisxdrive]

https://www.wheel-size.com/calc/?whe...cl=30mm&sr=0mm

I didn't notice your text until later..sorry
Chris

[schnell325]

That unfortunately, is beyond my suspension knowledge. Though

Why not use the ET54 rims?

But I’d be more concerned about increasing the rolling diameter by at least 4%…I didn’t know if this is within allowable tolerances for the xdrive / ABS computers.

[Erebor]

Well, the 19" wheel of the 235 has 235/35 tires on it, there is a margin for bigger ones, but 225/45 18 is even bigger than that. Do you have the adaptive suspension? If so, the bigger tire might touch the strut.
To improve the driving comfort, id first suggest to check the tire pressure and lower it. Whats the pressure on your car? I'd start with around 35psi, but wouldnt go below 32.