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[CaptJack]

Since I couldn't find any any other threads on this issue and the car's been out for a year now this may be a unique problem. However, 3 times in the last 2 mos. I have found the rear tire pressures down to almost "zip" and NO "Pressure Warning"alert!!!

1st time LR: 9 lbs., RR: 10 lbs.; 2nd time LR 11 lbs., RR: 8 lbs.; 3rd time (today): LR: 11 lbs., RR: 15 lbs.
Front tire pressures ok.

Here's the Facts:
E90 330i Delivered on May 5, 2005 (1st of this whole group I believe)
Sport Pkg. (Bridgestone run-flats)
Milage: 10,380 mi.
Maintained Tire Press: Front - 32 psi; Rear - 36 psi. (As per manual)
No nail/screw holes, no cuts, no bead or rim damage.
No indication that anyone has messed with the tires (No dust smudges on stem caps - I powdered these to check for tampering)

What the hell is goin' on??

The big problem here is that you can drive on these run-flats virtualy without ANY pressure and unless you get into serious cornering, never know it, unless the "Pressure Alert" light comes on. Those of you around here for the original e90 roll-out may recall that BMW had it's dealers drive these cars in the intro affair with NO (0 psi) air in the rear tires on an autocross course. NO ONE ever realized that their was anything wrong with the car after running the course!

Any ideas Bimmer Heads???

[jc777]

Did you initialize the warning system?

[tctic]

It's not about initializing the system. Both his rear tires are loosing pressure myteriously presumably measured by a tire pressure metre. Well.. the air some how did escape so I think it must be two defective tires at the rear.

[jc777]

Obviously there is a problem with the tires/rims or the manner in which they were mounted. I'm suggesting that the lack of warning might be due to improper system initialization.

[voltron1011]

There is a lot of members (myself included) who've noticed that the RFT's tend to lose air a bit quicker than traditional tires. My pressure seaped down to about 19 one time, and it was only about a month since I had last checked them.

[HRC]

Originally Posted by voltron1011

There is a lot of members (myself included) who've noticed that the RFT's tend to lose air a bit quicker than traditional tires. My pressure seaped down to about 19 one time, and it was only about a month since I had last checked them.

Yes, common problem with runflats. Alot of Mini Cooper people are pissed because of this and other RF attributes.

Danny

[Jesse Wilson]

I have it on my rear passenger tire. I have to had about 5-10 psi about once a month. All the other tires stay the same PSI all the time.

Go figure..... one of these days i'll have someone look at it but until then I just keep topping it off everytime it gives me the warning.

Jesse

[TheTwinz]

Originally Posted by Jesse Wilson

I have it on my rear passenger tire. I have to had about 5-10 psi about once a month. All the other tires stay the same PSI all the time.

Go figure..... one of these days i'll have someone look at it but until then I just keep topping it off everytime it gives me the warning.

Jesse

weird stuff.. i'm having the same exact problem with my rear passenger tires. always having to add more air every 2 weeks.. fricking annoying.

[e90pilot]

Wow I've never even heard of this problem. I ran three sets of runflats (2 pirelli and 1 bridgestone) and the only time they leaked is when there was a nail in one of them or I had a cracked wheel.

[1QuikWS6]

Don't know about the tire problem, but don't the TPMS sending units on wheels have batteries?

If yours use the batteries, I understand that the lithium batteries mounted in the sensors have a 5-6 year shelf life - which would put them at the end of their useful life if your car is 2005...