2014 BMW i3: Flat Tire and No Spare
May 14, 2015
"If only I had just gone my normal route. I shouldn't have tried to outsmart traffic." These are the thoughts that entered my mind as I stared at a flat tire on our 2014 BMW i3 on a freeway off-ramp in Inglewood.
I was commuting to our offices in Santa Monica and decided to forgo my normal route to take advantage of the HOV lane on Interstates 105 and 405. Traveling happily in the sparsely-populated lane, I whizzed by vehicles caught in the slog of post-dawn LA traffic.
Then I heard the chime of the tire pressure monitoring system. The i3's TPMS system displays air pressure in each tire, and the recommended cold pressure the front tires is 33 psi. The driver's side tire was reading 20 psi. A few seconds later, it dropped to 16. Time to get off the freeway. Now.
Two minutes later, I safely crossed all lanes and found an off-ramp wide enough to get out and assess the situation on the driver's side. When I stopped the car, the monitor displayed 0 psi. I hoped the system was malfunctioning. Then I saw the wheel resting on the road with only a thin band of rubber separating the two.
Unlike most BMWs, the i3 does not have run-flat tires. Instead, it's equipped with a sealant and inflator kit located in the front trunk. To use it, the inflator is attached to the can of sealant, which is in turn connected to a hose that pumps air and sealant into the tire through the valve stem. I could find no puncture in the tread or sidewall, so there was little to do but take the necessary steps and hope it all worked.
I inflated the tire to the recommended pressure and set off. The monitor took a minute or two to recalibrate and eventually registered 26 psi in the damaged tire. I was initially alarmed that the sealant didn't work, but the pressure held. Either the monitor or inflator gauge was off. With normal traffic I was traveling slower than the 50 mph limit imposed by the sealant kit. I saw no need to fill the tire with more air with 10 miles until my destination. The owner's manual calls for the tire to be replaced as soon as possible, so after I got back to the office I ordered a tire from Stokes Tire Service.
We went to Stokes the next day to get the new tire installed. The puncture on the old tire was in the tread, pictured above. Our advisor theorized that a screw had dug into the tire and dislodged, which explained the sudden loss in pressure. We also replaced the can of sealant so nobody else gets stranded on the freeway that early in the morning.
(We paid about what some commenters speculated in an earlier post about the i3's tires, plus mounting and balancing, but it didn't take a week to order what some thought would be a rare, sparsely-stocked tire.)
Cost of tire, mounting and balancing: $207.62
Cost of replacement sealant can: $50.82
Cameron Rogers, Vehicle Testing Assistant @ 4,284 miles