We put BMW run-flat tires to the test and give them a thumbs-down
We recently had an unplanned opportunity to put run flat tires to the test. Our impromptu test vehicle was a 2013 BMW X3 xDrive 28i crossover. During a Sunday trip to a park we had a puncture that gave us the chance to see how a run flat preforms while driving deflated, as well as explore the repair/replacement options and see how they might compare to other road hazard management options like a full size spare or temporary spare. We learned quite a bit from the experience and hope you find this information helpful if you’re considering a vehicle with run-flat tires.
We first noticed the flat when we re-entered the vehicle because the car told us the front left tire was low via the information screen. A system like this is now government-mandated on all modern cars. Hoping it was just low, and not completely flat, we looked at it closely and could see it was definitely flat. Moving the car slowly with the window down resulted in the crunchy sound of a flat tire and the feeling was noticeably wiggly and sloppy. The sound was so much of a concern we opted to call BMW via the car’s SOS button. After reading, re-reading, and then re-reading the VIN about 6 times to the BMW representative after they already knew us from our name and model number, not to mention the account we called from (frustrating), the person at the other end told us to ignore the sounds and feelings and drive it under 50 miles, and under 50 miles per hour, to wherever we wanted to go. She said as long as we didn’t smell burning rubber not to worry. Off we went.
Run flat tires work by using a much more robust sidewall construction. The stiffer sidewall is able to support the uninflated tire temporarily. However, driving on the tire without air pressure destroys it. In their marketing, makers of run flats try to compare older tire technology to their new, lower-profile tires with the stiffened sidewalls, and claim some safety benefits. We are skeptical. Blow-outs and complete tire failures on new, lower-profile, modern tires (not run-flats) are extremely rare.
Update - Read What J.D. Power and Associates found out about Run Flat Customer Satisfaction and replacement frequency - Added March 27, 2015
My passenger input in a Nav course home (14 miles) that did not use freeways. The excellent BMW Nav system made this pretty easy to do, although we did have to wait a few minutes while it would only display a warning message about the tire. As we drove my passenger also called the BMW dealership the car is serviced at. To its credit the dealership did answer, but since it was Sunday, they could not help us in any way. Take note of that. Next my passenger looked up the local tire place she services her Honda Fit. It was also closed. We looked for a third place along our route home, also closed. Our plan became, “let’s get it home and then deal with the issue Monday morning.”
Driving BMW On a Run-Flat Tire
The feel while driving the BMW X3 xDrive 28i crossover with the deflated run-flat was just what one might expect. Sloppy, pulling to the side of the flat, and pretty apparent something major was up. It would be very hard to ignore this even if the dash wasn’t constantly telling us about the issue. We looked in the owner’s manual, which is the size of three Korans, and in the section under flat tires it had a note about the 50/50 miles driving, and that was pretty much it. I mainly wanted to know if I should try to re-inflate the tire. I figured that would help, but I wanted to also make sure it would not cause a rupture of the sidewall. I saw a gas station with an air hose and pulled in. I checked the pressure and it was “0.” I pumped it up to 45 psi. Driving off the car felt dramatically better, but still slightly odd. 4 miles later we were again flat. I found a second station with a lousy air hose and put in about 20 psi. Again it felt better than flat.
The sounds of the car on the flat were the most alarming. It sounds like rubber crunching and is pretty loud. I ignored it. Keeping our speed steady and slow (about the 30 to 35 MPH speed limit) we got the car home OK.
Dealing With the Run-Flat Repair
The BMW dealer was much farther away than the local tire chains, so a local place became our repair plan. Travelling to the BMW dealer would have taken us close to our limit of 50 miles and it was also out of the way for our Monday work plans. Calling around we found that a local Town Fair Tire chain only 6 miles away had the ability to replace our Pirelli Cinturato P7 245/50/18 run flat. Here is the first point we wish to make. This was a puncture from a nail in the middle of the tread. If we had a spare we could have easily put on the spare, driven home and then to a tire place to have the puncture repaired properly (inside patch/plug, tire-off method). That would have either been free, or done for a nominal fee of less than $50. Instead, we are now looking at replacing a tire.