[nnj2024]

New BMW owner needs some help on M850i gc tire size.

I read through almost all tire-related threads on this forum but still have some questions.

I am planning to replace stock summer tire (245/35/20 Front, 275/30/20 Rear) to all season (245/40/20 Front, 275/35/20 Rear). Reason is there are too many potholes in my area.

If anyone has done the exact or similar upsizings, could you share:

1. Does this void any warranty on the new car?

2. Will the upsized taller tires rub and affect your normal driving without doing any adjustment? I am not that an enthusiast...so long as the car can still drive normally, I am happy.

3. If you have upsized and did adjustment, what are the adjustments?

Thanks for your help if you can shed some lights on this.

[John H.]

I've spent time in CLE and NE OH. I am very familiar with tire swallowing pot holes, salt, and snow hidden obstacles.

I guess your SA can give you trouble for not running specific tire sizes but highly unlikely.

In my opinion, the height increase is minimal, and you should not experience any issues.

Keep your summers. Invest in a winter set.
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[nnj2024]

Originally Posted by John H.

I've spent time in CLE and NE OH. I am very familiar with tire swallowing pot holes, salt, and snow hidden obstacles.

I guess your SA can give you trouble for not running specific tire sizes but highly unlikely.

In my opinion, the height increase is minimal, and you should not experience any issues.

Keep your summers. Invest in a winter set.
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Thanks for the quick help. Your information is really useful. I've had three tire bubbles in the past 6 years by running through potholes, all happened to the front passenger tire.

Based on the information you shared, the increase in front tire sidewall height is like minimal (0.5'') and probably will not make that much a difference when running through potholes again.

I think I will take your advice and invest in a winter set, which makes more sense.

Thanks again for the details! I really appreciate it.