2007 Mini Cooper S: Run-Flat Tires
August 08, 2007
Even before the Long-Term intro went "live" (the green flag that allows us to commence blogging) I'd suffered a "Low Tire Pressure Event" in our spanking new 2007 Mini Cooper S. Without planning to, I conducted an impromptu test of the Tire Pressure Monitoring System (TPMS) and the Dunlop run-flat tires.
As I fired-up the 'Coop to drive to the office one recent morning, I was greeted by a large yellow low-tire warning lamp smack-dab in the middle of the dash. Impossible to overlook. Getting out to check, none of the tires looked low. Not surprising with run-flats.
A couple of miles later I was at the nearest gas station, checking pressures: 40, 40, 40, 30. A-ha! The right-rear tire is 25% low - the precise point at which TPMS systems are required to flag a warning.
I added air and listened for leaks. Nothing. It's holding steady. It takes but a few moments to reset the TPMS light using the mutli-function display stalk. (Note: many competing TPMS systems reset themselves when air is added.)
Since I had both TPMS and run-flats, it was safe to continue the trip to work. No problems. No repeat of the TPMS warning.
At Stokes Tire, the trusty local outfit we usually use, the source of the leak was revealed: A nail at the innermost edge of the innermost rib of tread. "Can't be fixed," they said, "too close to the sidewall. You'll need a new one." But their distributor doesn't yet have access to the tire, a Dunlop SP Sport 01 DSST in size 205/45R17 84V. We move on.
So we called nearby Mini dealer(s). All said variations of the same thing: "We can't get that tire yet."
A few phone calls later we found a store that said they could get the tire. It would cost, gulp, $330 plus mounting, and we'd have to wait overnight for it to arrive. We bit the bullet. Only after the tire was mounted and balanced did we notice that it was NOT the exact replacement tire we had ordered. Someone had goofed. Off it came. With no replacement tire available, patching the tire was the only option.
Because rotation through the contact patch causes distortion where sidewall and tread meet, this patch might not hold. But we do have TPMS to clue us in and run-flat capability to get us home. There's always Tire Rack, which lists the tires in stock at $275 each. Mounting and balancing will bring that up over $300.
How did I pick up the nail? Two words: Model Homes. Avoid going to model homes. Besides the clear and present danger of getting new items added to your honey-do list, the places are likely to contain nails dropped by contractors working nearby. But damn, it shouldn't cost over $300! Each!
Dan Edmunds. Director of Vehicle Testing @ 1,318 miles