Dear Car Talk:
I bought a 2019 BMW 540Xi brand new. I love the car. But here is the problem: The car comes with run-flat tires and no place for a spare or jack.
I hit a pothole on the highway in the middle of the desert. Although the tires are run-flat, they recommend driving not more than 50 miles and at no more than 50 mph. Being much further than 50 miles from home, I needed to get towed into a dealer.
My question is, can I put regular tires on the car? Do I have to replace the wheels, too? The run-flat tires are low profile. Because of that, I have already had two cracked rims that needed to be replaced.
I would be happy to use the trunk for a spare, jack and lug wrench. — Don
Yes, you can replace the run-flats with traditional tires, Don. And you don’t have to replace the wheels. You’d want to replace all four tires, rather than mix run-flats with non-run-flats. And then you’ll need a fifth one and an extra wheel to toss in the trunk as a spare.
I don’t know if you’d need to do any reprogramming to the tire pressure monitors, but your BMW dealer can answer that question for you since they sell this car with both types of tires. If I were you, I’d also ask your dealer to tell you the highest profile tire size that will fit on your car.
Your low-profile tires, combined with your apparent lousy driving, Don, are causing those cracked rims. Low-profile means short sidewall. And, because there’s so little sidewall between the road and the wheel, when you hit a pothole or drive up onto the sidewalk to park and get coffee, it’s very easy to dent or damage those rims. And, as you know by now, they’re extremely expensive to replace.
So, a higher profile tire will give you more sidewall and more rim protection. It’ll also make the ride more comfortable and quieter — as will the non-run-flat tires, by the way. The higher profile tires might make the handling of your 540Xi a tad less sharp, but at $1,000 a wheel, that’s probably a trade-off you’re ready to make.
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