How To Fix A Flat On A BMW

I am on a business trip to San Jose.  In an ill-advised attempt to be somewhat self-sufficient, I opted to drive here from San Diego, rather than fly and rent a car.  After all, I drive a BMW…the drive would likely be pleasant, or at least not unpleasant, and I’d have the use of my own car while here.

That was my logic, anyway.

So it was that I found myself moving along with early afternoon LA traffic.  Feeling rather smug, I was, too.  

“DING!” said my car, in her polite way.  Her name is Giselle.  She says, “Ding!” whenever anyone riding in her has forgotten their seatbelt, or if a door isn’t fully latched, or if the parking brake is not fully released.  She is very polite, and this surprises most people, who expect her to be very German.  I have no idea what this means, but most people say it, so presumably people expect the car to alert me to a passenger’s Seatbelt Infraction by sounding a U-boat diving klaxon and shining the errant passenger’s individual map light on them.  

A-OOO-ga!  A-OOO-ga! Eine passagier sicherheitsgurt ist nicht gewölbt!

No.

Giselle simply says, “Ding!”

I am sure she’d whisper it if she could.

But getting back to my story, I was in the far left lane, the ostensible fast lane, traveling at about 15 miles an hour (in a 65 mile per hour zone), when Giselle dinged this warning:

“You have a flat tire.”

That was the important part.  There were instructions on the video screen that needed to be scrolled through to be fully read, which is not what one should do while driving in traffic with a flat tire.

As it turns out, I have run-flat tires, which I was a little skeptical of when I got the car, but now, having been told by my car that I have a flat tire while driving on the freeway in Los Angeles, I must say I fully appreciate the concept of the run-flat tire now.

I grok run-flat tires in fullness, as Heinlein would say.

I put on my hazard lights, and made my way to the next exit.  (I must add here that hazard lights seem to be much more effective than mere turn signals when one desires a lane change in LA traffic.  I don’t recommend abusing this knowledge, but it’s nice to know it’s there, you know?)

I found myself a gas station, pulled in and got out to examine my tires.

None of them were flat.

Now, never having actually seen a run-flat tire perform its sacred task, I speculated that perhaps it might not look any different when running sans air, so I checked the tire pressure in all four tires.  Both rear tires were at 41 psi.  The right front was at 41 psi.  The left front was at 39 psi.

Hmmm.  Not that big a difference, but to be on the safe side, I filled the left front to match the other three and started the car again.

Still getting the indication of a flat.

So, I asked the gas station cashier for directions to a tire place.

He sent me to his cousin’s place down the street.  

To be fair, it might not have been his cousin, but it was another 76 station and the proprietor was also Middle Eastern.  So it’s possible that this was, in fact, his cousin’s place.

The guy at the second station made me wait while he checked the pressure in all four tires of another flustered driver and sent him on his way.  Then he checked the pressure in all four of my tires and concluded that the sensor was probably bad and suggested I take the car to my dealership for service.  The other customer had exactly the same issue, he said.

He gives me vague directions to the BMW dealership in Glendale, which I find easily, but can’t figure out how to get into because it’s under construction.  Two trips around the block later (growing increasingly nervous, as I may very well be driving on a punctured tire), I find my way in.  

The receptionist is very apologetic about the fact that the service department is 8 blocks away.

I head to the service department.  

I explain my predicament to the receptionist, who makes a call, and then tells me that they can schedule me an appointment for Thursday.

It was at this point when my frustration got the best of me.  “Thursday?  I need an appointment to have a flat tire?”  I stop, take a breath, and less psychotically explain that I am already 140 miles from home and that I am en route to San Jose on business.  Thursday is out of the question.

She makes another phone call.  The service department doesn’t handle tires, anyway, but she can give me directions to the shop where they refer all their tire work.  I explain that someone needs to at least reset the tire sensor for me before I go to the tire place.

One of the service representatives walks me out to my car and shows me how to do it.  I is actually very easy, and I had thought of performing it myself, but wasn’t sure I could.  He makes me promise to get the tire looked at, gives me directions to the tire place, and sends me on my way.

At the tire place, they removed the wheel, examined the tire and found…

No.

Puncture.

Not even a slow leak.

I asked the tire guy to set all the pressures correctly, and while waiting for the chance to back out of the stall, I reread the section of the owner’s manual on the flat tire sensing system.

If the system, when active, senses that one wheel is spinning faster than the other three, it knows that the only way this can happen is if the tire is somehow smaller than the other three.  Low tire pressure makes the tire smaller…who knew?  According to the manual, a difference of only 3 psi between tires will trigger the alert.  

As you and I now know, the system works exactly as it should.

For the remainder of the drive, I kicked myself for not checking the tire pressures…as I should have…before beginning a 460 mile road trip.  I assumed that the service inspection I’d had done on the car just a few hundred miles ago would have set the pressures on the tires correctly, and that I had one less thing to worry about.

Writing about this tonight, I realized that the front tires were over-inflated, and that undoubtedly contributed to the leak in the left front.  I still should have checked the pressures, but I would have set the pressures to the same for all four tires, just as had been done by the dealership a couple weeks ago, so I wouldn’t have avoided the problem.

With the tire pressure set correctly…I got two miles to the gallon more than I expected.  The little excursion off the freeway in Glendale cost me two and a half hours, but not a dime otherwise, and actually saved me money by improving the gas mileage.

Funny how things work.