No TPMS

[Anonymous]

I just bought a set of Style 103 'Double Spoke's (oem for 3.0's) to use for winter wheels. When the tyres were removed for refurbing there were noTPMS units.

I assume it's economically unviable to fit some?

 

[srhutch]

That's because there are no sensors. It's done using the AbS sensor, nothing to do with the wheels at all.

 

[Anonymous]

So it's not the same system as on the E9x's? They have sensors in each wheel & I thought late E46's did too.

How does the ABS monitor tyre pressure?

 

[Ewazix]

The ABS measures the wheel rotation speeds and a flat has a different rolling radius. If one wheel is turning with 25% difference the systems raises the alarm. The only problem with this system is it won't tell you when all four tyres are under-inflated, even dangerously as there is no 25% difference. e.g. if you don't check the pressures regularly or it's been parked for a while.

 

[parlivus]

So it's not the same system as on the E9x's? They have sensors in each wheel & I thought late E46's did too.

How does the ABS monitor tyre pressure?

The E92 didn't have any sensors in the wheels, it was all done on the rotation of the wheels.

If the steering angle sensor is 0 and the ABS system detects that one wheel is moving faster/slower than the the other for a significant period of time then the circumfrance/rolling resistance of one of the wheels is likely to be different. Usual culprit is a lower tyre pressure.

 

[GregZ4]

So it's not the same system as on the E9x's? They have sensors in each wheel & I thought late E46's did too.

How does the ABS monitor tyre pressure?

The E92 didn't have any sensors in the wheels, it was all done on the rotation of the wheels.

If the steering angle sensor is 0 and the ABS system detects that one wheel is moving faster/slower than the the other for a significant period of time then the circumfrance/rolling resistance of one of the wheels is likely to be different. Usual culprit is a lower tyre pressure.

The light also comes on quite merrily if the tracking is out and an alignment is needed as I discovered around 2 years ago upon buying mine.....

 

[Anonymous]

The E92 didn't have any sensors in the wheels, it was all done on the rotation of the wheels.

Well, ok.

So what are these?



There are also similar ones for the E46, X5's, 7-series et all.

 

[parlivus]

Well my E92 didn't have any, neither have any of the E9x cars I've worked on or seen tyres fitted too.

 

[Anonymous]

The link in my last post is to BMW TPMS sensors on eBay. There are loads for all models.

I'm sure the Z4 system works but it's hardly a pressure monitoring system. A deflation detector maybe but the term 'pressure monitor' implies it actively monitors the pressure in each tyre.

Still, I suppose it's better than nothing. I'm Old School - I like to check my tyre pressures once a week regardless.

 

[srhutch]

None of my E46's had them. Probably for US cars which do have them including the E85/6