[Cognac340]

Im about to lock in a trade for 405m wheels for my f30 340 xdrive but im worried about the possibility of blowing up my transfer case and other things of that nature current setup on them is 235/35/20 fronts
265/30/20 rears. Will this work for xdrive ?

[quixotemi]

Helpful video here:

Use this calculator: https://tiresize.com/calculator/

With your setup you'd be at -0.8% which is under the required 1%.


But your better question is whether you can run those 265/30-R20 tires without rubbing - for that I have no idea.

[johnung]

Originally Posted by Cognac340

Im about to lock in a trade for 405m wheels for my f30 340 xdrive but im worried about the possibility of blowing up my transfer case and other things of that nature current setup on them is 235/35/20 fronts
265/30/20 rears. Will this work for xdrive ?

What brand/model tire do you plan to use? Tires can vary and the sizes on the sidewall are only manufacturer ballparks, making Internet calculations based on them not accurate enough.

Look up exact measured tire diameter on TireRack website in each tire's Specs section. If front/rear difference is 0.2" or less then it's okay, within 1% difference. But 0.3" or greater could risk $4,000+ Transfer Case.

[J555]

I am afraid nobody can confirm this setup will not cause x-drive to judder/jerk, especially when launching or low speeds. The correct setups are either 225/35 + 255/30 (BMW standard) or 235/35 + 275/30 (not recommended for 405m, as the rear rims are only 8.5" wide). In general, the x-drive on F30 is far more sensitive to smaller rear diameter than vice versa.

If you have a chance to test it on your car, do it and pay attention to slow launches, hesitation of the car during acceleration from very low speeds, and small jerks during braking, when stopping the car. If not, measure the diameters - what calculators say can be pretty different from the real world (and in your case, the front tires are slightly stretched, while the rears slightly bulge). If you can't do the test drive or measure it, you're at risk of either need to switch the tires or sell it.

You don't need to worry about blowing your transfer case with this setup, though - it ain't so easy, and would probably need (many) thousands of miles.

[shiftdnb]

If you're looking for more sidewall 235/40 and 265/35 work as well.

[J555]

Originally Posted by shiftdnb

If you're looking for more sidewall 235/40 and 265/35 work as well.

No way, it's a great 19" setup, not 20".