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Discussion Starter · #1 ·
I currently have an '06 530i with the FTM (flat tire monitor) system. I do not have the TPS (tire pressure sensor). The car was a CPO and was purchased about a month ago. It came with run flat tires. I had an issue yesterday where one of the tires was 11psi too low and the FTM system did not alert me. I just found it with a routine tire pressure check (the first one I did).

Some people say that you cannot use run flats with the FTM system because the run flats do not decrease in diameter when air is lost. They say you must have the TPS system for use with run flats. Is this information correct?

Thanks
 

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Discussion Starter · #2 ·
Got it figured out. It appears that the FTM system will work fine with run flats.
 

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I've got a somewhat related question for Gary -

I damaged the left front wheel and tire (RFT) on my 2007 335 over the weekend. The wheel is hopefull being repaired, the tire did not make out so well. Given that I need to replace both front tires is it ok to replace them with non-RFT tires? Then, once the rear RFT tires have worn out I can replace them with non-RFT as well.

I am looking at purchasing the Michelin PS2 tires, non-RFT.

Thanks for your help!
 

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Although we cannot officially recommend mixing non runflat tires with runflat tires due to their different sidewall stiffnesses, there isn't a technical reason why they wouldn't physically fit.

I would caution you that the PS2 has higher grip levels that the OEM runflat Bridgestones, so you'll be increasing front grip without increasing rear grip at the same time. I'm not sure if the factory built-in understeer will be enough to compensate, so be sure to use caution driving on this mixed setup until you're able to get used to how your car handles. Leave DSC traction control on for sure.

Tires http://www.tirerack.com/a.jsp?a=AB2&url=/tires/index.jsp
 

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Thanks Gary!

I have been investigating the PS2 NON RFT tires. According to the Michelin website there are two models of this tire with different load ratings.

The front, 225/40-18 is available in either 93617 (XL) or 84568. According to the site, the first model number is for Audi and Daimler/Chrysler and it has a greater load rating than the second model number. The second model number is identified as BMW.

Similar for the rear tires, 255/35-18 is available with either 45327 or 15999.

I can not find the BMW specific tires for the front on the Tire Rack website. I think that Tire Rack is listing the BMW tires for the rear since the tire designation does not include the XL.

Gary - can you provide some insight on this? Does Tire Rack have the BMW tires?

Thank you again for your help and support!

Andy
 

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Your car can use either XL tires or standard load tires.

In 255/35R18 there isn't a PS2 that is BMW specific. In fact there is only one version of the tire, and it happends to be an XL tire, the 45327. The 15999 is the PS2ZP runflat tire. Same story for the 225/40R18...just one non runflat is available and it is an XL tire, which is fine.
 

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I actually contacted Michelin about this before I posted my question above. Turns out that my confusion over the part numbers is because the Michelin website does not identify the 84568 and 15999 as ZP (RFT) tires. Glad this is resolved.

Thanks Gary!!
 
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