How To
John Paul, AAA Northeast’s Car Doctor, answers a question from a BMW owner wondering whether it’s best to replace all four tires at once.
Q. I just replaced the front tires on my 2006 BMW 330xi. The tire shop said because the rears are at 5/32, that is too much difference from the new front tread depth, and running the car with two new front tires and half-used back tires will damage the transfer case. Should I replace the rear tires also? I looked in the owner’s manual as well as my BMW repair guide and found no reference to replacing all four tires at the same time. What happens if I had a blowout on one tire, would I need to replace all four?
A. Looking at other makes and models of all-wheel-drive vehicles, most state if there is more than 4/32 difference in the tires, it is possible over time to damage the drivetrain. If this were my car, and I planned on keeping it a good long time, I would replace the other tires and sell the used tires. If you damage one tire and the other three are in good shape, you can buy one new tire and have it shaved down to the tread of the other three. Also, as a side note, when only replacing two tires, the new tires should go on the rear of the vehicle, not the front.
Q. Like most people I’m online a lot and see people doing reviews of products, especially on TikTok. When you, the Car Doctor, mention a product, are you paid by the company?
A. No, I have never been paid to do a review of any product, although it has been offered. I do from time to time receive products to evaluate. The products that work as advertised I will mention. In a past column I mentioned the Garmin dash cam. Over the years I have purchased Garmin GPS units, I like their quality and…