Question on TPMS, switching out tires/rims

[yvel26]

Originally Posted by Caddyshk

We don't have TPMS sensors in the wheels...

So M's don't have them? So how do they measure air lost in the tires?
I also have ordered new wheels and I am wondering if I need to order some extra TPMS.

Thx.

[onebluemcm]

Originally Posted by yvel26

So M's don't have them? So how do they measure air lost in the tires?
I also have ordered new wheels and I am wondering if I need to order some extra TPMS.

Thx.

The change is '06 to '07 across all Z4 models. It depends on the year of your car.

'06 and prior, pressure is monitored indirectly by the car monitoring wheel rotation. As a tire loses air pressure the rotation of the affected wheel is altered, I think by having a slower rotation relative to the other wheels but I'm not entirely sure how it works - regardless, the car can sense this relative change in a deflating wheel's rotation and the indicator will come on. My '04 E46 M3 had this system.

'07 and up, pressure is monitored directly by a device attached to the valve stem inside the tire. The entire system is different - '07 sensors don't work with the prior systems, and wheels without sensors will cause the indicator to come on in '07 and up cars. With the pre-'07 system, the tire has to deflate more than with the '07 and up system, relatively speaking, before the indicator light is set off because of the way the wheels are monitored - indirectly versus directly. This is the main reason for the change, to my knowledge.

I think I have this right - if not, please correct me.

Shipkiller is the man:
http://www.zpost.com/forums/showthread.php?t=456173
http://www.zpost.com/forums/showthread.php?t=456170

[RBull]

^I think that would be faster rotation as the diameter of the tire is reduced with less air.

The rest of what you're saying seems to make sense but I also don't know for sure.

[onebluemcm]

Yeah, that could be, but my thought was that as it loses pressure, there might be more rolling resistance which might slow it down relative to the others. Somehow, it must work, but I'm glad to have the newer TPMS....

[vasaline]

Hello speaking of TPMS, I'm getting new tires for my 06 M Roadster and wondering if my car has TPMS.

[vasaline]

Hello speaking of TPMS, I'm getting new tires for my 06 M Roadster and wondering if my car has TPMS.

[yvel26]

Originally Posted by onebluemcm

The change is '06 to '07 across all Z4 models. It depends on the year of your car.

'06 and prior, pressure is monitored indirectly by the car monitoring wheel rotation. As a tire loses air pressure the rotation of the affected wheel is altered, I think by having a slower rotation relative to the other wheels but I'm not entirely sure how it works - regardless, the car can sense this relative change in a deflating wheel's rotation and the indicator will come on. My '04 E46 M3 had this system.

'07 and up, pressure is monitored directly by a device attached to the valve stem inside the tire. The entire system is different - '07 sensors don't work with the prior systems, and wheels without sensors will cause the indicator to come on in '07 and up cars. With the pre-'07 system, the tire has to deflate more than with the '07 and up system, relatively speaking, before the indicator light is set off because of the way the wheels are monitored - indirectly versus directly. This is the main reason for the change, to my knowledge.

I think I have this right - if not, please correct me.

Shipkiller is the man:
http://www.zpost.com/forums/showthread.php?t=456173
http://www.zpost.com/forums/showthread.php?t=456170

Thanks man for this info.
So this will save me some money as I have a 06 Roadster M.
This is a good thing

[Caddyshk]

Originally Posted by vasaline

Hello speaking of TPMS, I'm getting new tires for my 06 M Roadster and wondering if my car has TPMS.

No