Tyre pressure monitor

Aircooler · 01-19-2010, 10:39 AM

My 2009 E91 330D has the tyre pressure monitor display on the i-drive. I'll be installing a new set of alloys with winter tyres (non-RFTs) for a couple of months. Will I get any kind of error light on the dash/i-drive since there won't be any sensors on the new wheels?

Maybe I'm missing something obvious and it won't be a problem but I don't know much about the car yet - only had it a few hours and then put it in the garage for a work trip abroad.

Em135eye · 01-19-2010, 10:42 AM

The TPMS works off the ABS sensor so it will be fine.

Aircooler · 01-19-2010, 10:58 AM

Quote:

Originally Posted by 335diesel

The TPMS works off the ABS sensor so it will be fine.

really? how does that check the pressure in the tyres? I always thought there was some kind of transmitter in the tyre valve assembly or similar.

Em135eye · 01-19-2010, 11:02 AM

Nope - it's to do with wheel rotation speed. A flatter tyre spins faster (I think) due to the reduction in diameter - or something like that.

It uses (nicked from xenon - lord of BMW facts!) the Hall effect (magnets) to work it out.

The wheel has nothing in it at all - just need to reset the TPMS every time you change the pressures - very simple to do.

xenon · 01-19-2010, 11:03 AM

Generally only on the US models. On the UK model the ABS sensors compare rotational speed - a tyre with low pressure rotates slightly quickers (as its diameter is smaller) and the warning light comes on. Doesn't detect a very gradual loss so you're wise to check the old fashioned way from time to time.

Edit - crossed post with 335d who gave the same answer.

Aircooler · 01-19-2010, 11:06 AM

ok, thanks guys - much appreciated. Im used to air/oil cooled 911s, so lots to learn about all this new technology

01-19-2010, 10:39 AM	#1
Aircooler New Member 2 Rep 23 Posts Drives: E91 (2009) Space Grey Join Date: Jan 2010 Location: Surrey iTrader: (0)	Tyre pressure monitor My 2009 E91 330D has the tyre pressure monitor display on the i-drive. I'll be installing a new set of alloys with winter tyres (non-RFTs) for a couple of months. Will I get any kind of error light on the dash/i-drive since there won't be any sensors on the new wheels? Maybe I'm missing something obvious and it won't be a problem but I don't know much about the car yet - only had it a few hours and then put it in the garage for a work trip abroad.
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01-19-2010, 10:42 AM	#2
Em135eye Banned 178 Rep 4,302 Posts Drives: M135i Join Date: Jul 2009 Location: South West iTrader: (0) Garage List 2014 BMW M135i 5 door [0.00]	The TPMS works off the ABS sensor so it will be fine.
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01-19-2010, 11:02 AM	#4
Em135eye Banned 178 Rep 4,302 Posts Drives: M135i Join Date: Jul 2009 Location: South West iTrader: (0) Garage List 2014 BMW M135i 5 door [0.00]	Nope - it's to do with wheel rotation speed. A flatter tyre spins faster (I think) due to the reduction in diameter - or something like that. It uses (nicked from xenon - lord of BMW facts!) the Hall effect (magnets) to work it out. The wheel has nothing in it at all - just need to reset the TPMS every time you change the pressures - very simple to do.
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01-19-2010, 11:03 AM	#5
xenon Major General 1471 Rep 8,200 Posts Drives: 2021 G21 330i M-Sport Join Date: Jun 2008 Location: Coventry iTrader: (0)	Generally only on the US models. On the UK model the ABS sensors compare rotational speed - a tyre with low pressure rotates slightly quickers (as its diameter is smaller) and the warning light comes on. Doesn't detect a very gradual loss so you're wise to check the old fashioned way from time to time. Edit - crossed post with 335d who gave the same answer. __________________ Ian Current: 2021 G21 330i M-Sport Previous: 2018 A6 Avant S-Line MMI+, 2014 F31 320d M-Sport, 2013 F10 520d M-Sport, 2011 F10 530d M-Sport, 2008 320i M-Sport Coupe, 2002 325i, 2001 318i valvetronic, 1998 318i, 1996 525i, 1990 Porsche 944S2
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01-19-2010, 11:06 AM	#6
Aircooler New Member 2 Rep 23 Posts Drives: E91 (2009) Space Grey Join Date: Jan 2010 Location: Surrey iTrader: (0)	ok, thanks guys - much appreciated. Im used to air/oil cooled 911s, so lots to learn about all this new technology
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