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[jhhl]

Hi,
I am new to this forum. I drive a 2011 335i X Drive, it came stock with Bridgestone run flat 225/40R18 at front and 255/35R18 at rear.My question is regarding Flat Tire Monitor, how fast should it warns be when I have flat tire?
On Dec-19, the warning came up on my way home from work, I stopped by gas station to check tire pressure, front driver side tire had absolutely no tire pressure in it, so I filled it up to 31psi and went home. Next day, I drove to local tire shop for repair, I was told the tire is not repairable, 2 nails was found and I drove too long with it (work to home and vice versa is less than 50km). Anyway, they happend to have have an exact tire in excellent used condition, that was sold to be for $275 + $18 labor. 2 Weeks later, on Jan-02-2012, as I was driving with windows down, I heard a weird noise, that sounded like metal hitting the road coming from rear tire, I drove to my office parking lot (less than 5mins away) and examine the tire, sure I saw a nail, I pulled it out, and as soon as it was out, I heard air started to come out. I was curious to see if the FTM will give me warning, so I waited about 1h until no more air coming out, then I drove to the same tire shop which is only 3 mins away. The FTM warning did not came up, again they found 2 nails, which I saw as well when the tire was unmounted. This time it was fixed for $55 + taxes this time.

My Question is what good is FTM, if by the time I get warning, the run flat tire is not good anymore? and the 2nd time, why did FTM warning failed to come on? Thanks for all answer!

[Yvette]

you must be living near construction zone? anyways after I swapped to winter mode, my ftm showed up like 6 times now, everytime I check air pressure they are fine, so I kept reseting them. and once 4 days, ftm shows up again, I am going to go talk to my dealer for this....

[MTibbs]

You CAN plug a runflat....I have done more than once due to a nail and had no problem. Anyone who tells you otherwise probally want to sell you a tire and make money. Secondly, don't pull nails out of your tire!!!! If you see one, wait untill you are ready to fix it to pull it out. That's what is holding the air IN. To answer your question in reguards to the tpms .... mine have always alerted me in due time, even when the tire was just low due to cold weather. Maybe you have a faulty tpms unit in that tire.

[jhhl]

Yes, I do work in lite industrial area, however what concern me the most is the proper functionality of Flat Tire Monitor. As stated in my initial post, the first flat tire ended up costing a tire, and the 2nd one I caught it myself with no warning from FTM...Sounds to be FTM is pretty useless. Is your BMW from US or Canada? I was told US version has Tire Pressure Monitor vs. Canadian version with Flat Tire Monitor; which one is more effective? And last should I make a complaint to BMW Canada regarding the useless FTM? Thanks

[Wires]

Maybe the FTM has never been reset? Could be blank, and assuming 0 PSI as "good".

I'd inflate the tires to spec, reset the FTM, drive around the block a couple of times, and then bleed off say 10PSI of air from the "questionable tire". If it doesn't come on, then the TPM is probably bad, and needs replacing.

[jhhl]

Originally Posted by MTibbs

You CAN plug a runflat....I have done more than once due to a nail and had no problem. Anyone who tells you otherwise probally want to sell you a tire and make money. Secondly, don't pull nails out of your tire!!!! If you see one, wait untill you are ready to fix it to pull it out. That's what is holding the air IN. To answer your question in reguards to the tpms .... mine have always alerted me in due time, even when the tire was just low due to cold weather. Maybe you have a faulty tpms unit in that tire.

I know you can plug a runflat, but providing you dont drive too long with it (in my case, I think less than 75km for sure). The tire shop told me is beyond repair. I do trust this tire shop, it is a reputable shop in my area that I have been going for over 15 years. The 2nd flat on Jan-02, I caught it myself immediately with out any warning from FTM, and it was fixed for $55. My main concern is that I am not going to be so lucky to caught the flat myself, so next time when FTM gives me warning, is it going to be too late for repair again?

[jhhl]

Originally Posted by Wires

Maybe the FTM has never been reset? Could be blank, and assuming 0 PSI as "good".

I'd inflate the tires to spec, reset the FTM, drive around the block a couple of times, and then bleed off say 10PSI of air from the "questionable tire". If it doesn't come on, then the TPM is probably bad, and needs replacing.

Thanks for the reply. I did reset FTM after the 1st flat and tire change. The shop mechanic briefly told me how FTM works; it senses the balance of the tires to detect flat? I didnt quite understand, I will do some research and read up on it. As for testing you mentioned, I will let the dealership do it, since we pay so much for a premium car, might as well let them look at it.

[Tom K.]

Originally Posted by jhhl

Thanks for the reply. I did reset FTM after the 1st flat and tire change. The shop mechanic briefly told me how FTM works; it senses the balance of the tires to detect flat? I didnt quite understand, I will do some research and read up on it. As for testing you mentioned, I will let the dealership do it, since we pay so much for a premium car, might as well let them look at it.

Your FTM system senses the tire's rotational speed and compares it to that of the other tires - if there is a discrepancy, the warning goes off. I suspect this arrangement would take longer to "warm-up" than the US mandated TPMS which uses individual wheel sensors to report the actual pressure of each tire.

Tom