Old Tire Replacement on My BMW Gran Coupé: A Run-Flat Story

Cars · Published 7/4/2026 ·

A month ago I brought home this Gran Coupé. One of the rear tires kept throwing a low-pressure warning and giving me grief, so I took it to a tire shop. Here’s how the swap went.

It had only been a month since I bought the upper-trim wheels and tires, and the tires that came mounted on them were 2019 Bridgestone AO tires — in other words, the factory tires that ship on an Audi A5. They were run-flats. But that wasn’t the real problem. Run-flats have very stiff sidewalls, while the contact patch has to stay soft enough to grip the road properly. The seam where those two parts meet had hardened to the point that the tire couldn’t really do its job anymore, and somewhere in that gap — I couldn’t tell exactly where — air was slowly but steadily leaking out.

And then another problem… on a wheel I’d only mounted a month ago, one of the bolts just would not budge. Two of us worked at it for over ten minutes and it still wouldn’t come loose, so in the end we had to wreck the bolt to get it off.

The stubborn wheel that wouldn’t come off…

The fronts are still good, so I’m leaving them alone. I went with 19-inch wheels and tires just for the look — but honestly? It’s taking a bit of time for us to become friends.

Here are the engineers, deep in thought.

In the end there was a whole process of destroying the bolt, tapping it out in reverse, and separating it. Meanwhile the wheel on the other side came off in no time…

I don’t know why, but that spot is always rusted. Even so, it’s rusted less than usual because I’d done some anti-corrosion work on it. This is how cleanly it’s supposed to come apart…

The undercarriage is still in decent shape — and this is a car that’s already ten years old…

Eventually we got it out, and I drove home with only four of the five bolts fitted. Naturally I ordered the missing one right away, and once it arrives I’ll have to go back to get the bolt fitted. While I was ordering, I decided to get rid of the wheel-lock bolts (the anti-theft ones), since they’re a headache if anything goes wrong… so I paid a bit extra for that.

Because of budget constraints, I carefully picked out a good-condition used tire and had it mounted. Brand-new is obviously best, but since I don’t even know how long I’ll keep the car, I decided to make peace with my wallet.

A 2022 Michelin all-season tire with about 80% of the tread left.

Here’s the problem tire. As I explained above, the seam is a mess. It’s all hardened — honestly it feels like the cords are basically severed. The guy told me the answer with run-flats is to run them exactly three seasons and then replace them.