What size spare do I need if I run 20"s

[Iaro]

Can somebody tell me what size spare do I need if I run 35/20 and 40/20? Would regular 155/90/18 work?

[MN2///M]

Rim size really does not matter, it is the overall circumference of the tire/rim combination. If you are running stock BMW combinations, then the stock BMW space saving spare tire would be the one to go with unless you want a full size spare. The only issue with a full size spare is that I don't believe it will fit in the compartment below the rear cargo floor.

Here is a link you can use to obtain tire circumference for whatever size combination's you are interested in:

https://tiresize.com/comparison/

[Iaro]

It seems 19" from f85 will have the closes revs and diameter

[P1]

Why not just buy the OEM spare donut?

[Iaro]

Originally Posted by P1et

Why not just buy the OEM spare donut?

Yeah that's what I'm talking about. I just wanted to know what is the closest radial size.

[P1]

Yes, the OEM spare will work whether you have 19s, 20s or 21s.

[d_v_o_1]

So for 22's the only option is a full size spare?? Damn, I just picked up a set of 22's and was going to go salvage hunting for the spare tire kit. Any suggestions (other than road side assistance) for an affordable way to mitigate this dilemma? If the full size won't fit, is there a large donut tire that would compensate?

[spike5150]

Originally Posted by d_v_o_1

So for 22's the only option is a full size spare?? Damn, I just picked up a set of 22's and was going to go salvage hunting for the spare tire kit. Any suggestions (other than road side assistance) for an affordable way to mitigate this dilemma? If the full size won't fit, is there a large donut tire that would compensate?

Oem donut will still work, especially for short distance to tire shop. If you install M Performance brakes, or other large brakes, the you would need to get the X5M version of the donut spare.

[d_v_o_1]

Awesome thank you!!