Took my Z4 by my mechanic in Great Falls Wednesday for a quick check-up before rolling out to Cape Cod this week to discover my left rear run-flat was shredded and probably would have fallen off the rim in less than 20 miles. Replaced them with P-Zeros. Anyone else experience this??

You probably had a flat and drove on it for an extended period of time.

What happened to the tire pressure monitoring system that kindly give us so many false alarms!!!

Andy

if the tires lose pressure slowly enough, it may not catch it.

if the tires lose pressure slowly enough, it may not catch it.

It will and it does. On our ex-Z4 3.0, it had a slow leak that loses about 1-2 lbs per day. By the time it reaches ~20 psi the light came on to warn us. Now, if both tires on the same axle is losing air at the same rate then it won't catch it, because the older tire pressure system uses the difference in ABS sensor reading to determine pressure loss.

My speculation is the OP drove on flat tires without knowing they're flat. The tire warning system will only warn you once when you start the car, I don't think it keeps beeping. A light stays lit on the dash. So if the system is out of calibration or if operator did not heed the warnings, it is entirely possible.

Or both tires were flat.

Bingo...

I actually took delivery of my car with NO AIR IN THE TIRES... All 4 were flat.

No warning, Nada. I just got a little pedal happy and felt a wiggle so pulled into a gas station and bingo...

I filled the tires and drove to the dealer and they said "well looks good now". I told em I had driven 40 miles or so and they would have to give me something in writing that said the tires are perfect and will work as they should while flat for at least what the warranty says. The guy says "BMW and the dealership are not responsible for the tires." I just looked him in the eye and waited for him to kick his own ass by openeing his mouth again.

He did and they replaced all four brand new run flats...

When we took delivery on our first Z4 (used 04, 3.0i) one of the tires went flat after driving 100 miles. The tire pressure warning did not activate.

Since then I've done two thing without fail:
1. Check tire pressure weekly
2. Re-calibriate the warning system weekly or when I add/subtract tire pressure. If you don't realbriate the system it may not dectect small losses in tire pressure over time between driving(that could add up to big losses).

To recalibriate, with the car not moving (in or out of gear) press the tire pressure warning button (center console) until you see the warning light appear on the dash. Then drive the car. The light will go out signaling that the computer system has reset to the current pressures. Do this only if you've checked the tire pressures as you could recalibrate the computer to accept dangerously low tire pressures!

BTW after I began resets on our old car I checked the system (by lowering ressure in one tire and driving slowly around the block) and found that the system was in fact functioning OK.

Thsi only works on the 05 and older Zs and the 06 Z4M I'm not sure how the system works on the 06 and younger 3.0i and 3.0si.

OP Here:

Similiar situation to Frustrat1on's experience, the left side wheels were bent and the tires were flat when i bought it in February. Then, to add studpidy to injury, after replacing the tires, they installed the front on the rear and vice versa.

The tires had the steel belt poking through in some areas but the structural integrity remained. Of course the tire monitored went off right after placing the net tires on..........