# Can you tell if a run-flat tire is flat?



## ezatnova (Jan 14, 2006)

Now that BMW has apparently changed to an in-wheel monitoring system for the run-flats in the new 3 coupe, I am a little concerned about overall safety when switching to some 17" winter wheels/tires. As far as I understand, I will lose all run-flat monitoring since the sensors are in the stock 18" wheels. Can you feel if a run-flat is flat, or should it be made a point to visually check them every once in a while (can you visually tell?)? Will the dash throw some error light since the car will have wheels/tires without the sensor in them?


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## [email protected] (Jun 10, 2003)

As fas as we know, all tires on the 2007 335i will be run flat tires. You can confirm by checking the name of the tire on the sidewall. Different brands will have different designations for meaning run-flat. You can either accept the lack of pressure monitoring and ignore the dash light or buy an extra set of sensors to put in your winter wheels.

Wheels http://www.tirerack.com/a.jsp?a=AB2&url=/wheels/index.jsp


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## ezatnova (Jan 14, 2006)

[email protected] said:


> As fas as we know, all tires on the 2007 335i will be run flat tires. You can confirm by checking the name of the tire on the sidewall. Different brands will have different designations for meaning run-flat. You can either accept the lack of pressure monitoring and ignore the dash light or buy an extra set of sensors to put in your winter wheels.
> 
> Wheels http://www.tirerack.com/a.jsp?a=AB2&url=/wheels/index.jsp


Gary, I'm pasting your reply to another thread here since it is very relavent regarding the sensors, etc.

Now, any idea of the BMW lights blink forever or just at start-up, if we forgo the sensors in new wheels?

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Gary - "Correct. You can either accept the lack of pressure monitoring and ignore the dash light or buy an extra set of sensors to put in your winter wheels. Coming soon I'll be posting a list of 17" and 18" wheels that we carry that will accept factory sensors. I have confirmed that we'll be carrying the sensors as well so that you can purchase them at the same time you order wheels and tires from us. We'll them mount the sensors inside of the wheels, then mount and balance the tires. Sensor cost is currently estimated at $70 per corner. Due to the complications involved in this process I would recommend calling me directly to order or referenceing my name at the end of any online orders as your previous contact so that I can look over the order to be sure it is done correctly. Stay tuned for more info."


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## [email protected] (Jun 10, 2003)

I'll be making a sticky thread once we have more solid info as well. I currently don't have confirmation on what the light will do : ie flashing or solid, whether it is defeatable, etc. Anyone with knowledge of this that has been confirmed is encouraged to post it.


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## kylechan (Jul 23, 2005)

It stays on forever....
at least on my 07 525i
It says TPM malfunction on idrive for the first 10-20 seconds, and the TPM light flashes. After that, the TPM light stays on all the time.
It doesn't quite bug me but my wife doesn't really like it

My aftermarket BBS RGR wheel's valve stem hole diameter is too small for the two piece sensor. The sensor is made by Beru, check out beru.com and you can find an installation instruction PDF. I am thinking of strapping the sensor instead of mounting it as part of a valve stem, but haven't tried it yet. You can buy new sensors from the dealer or online, if it's online it's $40 per sensor/valve stem, total about $170 (including shipping). 
Email Garry at bmw of newport: [email protected]

To ensure fitment, you may want to see the valve stem hole of the winter wheels. it should be at least the size of the original wheels, plus it should have a flat mounting surface like the OEM wheels has.


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