Which wheel size for square tire setup where staggered setup was default one?

[svemirski_macak]

Hello,

I have 2010 BMW X1 xDrive. Default factory setup of wheel size was:
rear: 18 inch diameter, 9 inch width
front: 18 inch diameter, 8 inch width

With following tire sizes:
rear: 255/40/R18
front: 225/45/R18

I had some issues with transfer box and my car mechanic proposed me to go with squared tire setup.

My question is:
Can I put a new set of 4 SAME wheels with 18 inch diameter and 8 inch width and put 225/45/R18 tires (as it is currently just in front)?

Where can I check that kind of thing in the future? I've checked manual I received with my car and I couldn't find nothing there.

I would greatly appreciate any advice, issues with transmission box are driving me crazy. Or should I say xdriving me crazy.

[jakerazzz]

Can I ask what issues you are having? I’m having a shudder from 1st to second at low rpm. Thinking about changing tire to square setup as well as I’ve heard that helps

[svemirski_macak]

Originally Posted by jakerazzz

Can I ask what issues you are having? I’m having a shudder from 1st to second at low rpm. Thinking about changing tire to square setup as well as I’ve heard that helps

Exactly that, but it also happens when changing gears from neutral to 1st if I remember correctly. So this happened to me already several times. Each time was fixed by changing oil in xdrive transfer box. But it was about time to take care of source of the problem and not only the consequences.

Judging by what my car mechanic told me and what I've read on forums, it is due to different tire diameter back and front. Indeed, when I purchased this car, there were different types of tires back and front. Front were a bit more worn out and therefore having smaller diameter, which was probably causing the issue.

My car mechanic proposed me to put all the same tires with star on them (tires with star are approved by bmw). I bought 4 same tires, but then I realized my back wheels are wider than front and they won't fit same tires. In order to keep things as simple as possible now and in the future, I decided to put the same wheels and tires front and rear. Therefore my initial question.