Are runflat tyres without tpms dangerous?

snipnoob86 · 03-11-2016, 01:40 PM

So, i have just been doing some readin and i came across an interesting story.

A lady had RFT's fitted to her car and made generally short journeys. she had a badly damaged tyre, the entire inside edge was blown out and she was only made aware while her car was in for service. The length of time it was damaged for is unknown.

Ok, woman driver gaggs, how the hell did she not know. but the fact remains she did not and the car was unable to warn her due to no TPMS.

thoughts?

Chompers · 03-11-2016, 01:59 PM

RFT's have been on BMW's for ages. TPMS is a relatively new addition in terms of giving the tyre pressure at each corner, when a +/-0.2 bar difference between tyres on the same axle is noted by the TPMS an amber warning is given.

I will hold my hands up here and now and admit that I suffered the same fate as the woman you mention. The inside edge on one of my rears on my e61 was run down so low that it wires were visible

it was shear luck that I found it in this condition, and only because the kids ball went under the car. From that day on I have always checked the rear inside on a regular basis.

Peter-K · 03-11-2016, 02:17 PM

TMPS reports tyre pressure problems. Cars with run flats compare the rotation speeds of each wheel and throw up a dash warning - cross section of a tyre with an exclamation mark. A flat tyre has in effect a smaller diameter so will turn faster.

HighlandPete · 03-11-2016, 02:27 PM

Users are not supposed to fit run-flat tyres to vehicles without TPMS/TPWS.

With the older TPWS (indirect 'warning' system using wheel speed sensors) users are still prone to tyre issues if the system is not reset at pressure changes, or tyre pressures not regularly checked. All tyres can reduce pressure and there is no warning, plus there can be up to a 30% pressure drop before the warning bong sounds, with the indirect TPWS. TPWS can only really warn of a puncture, not slight drops in pressure which can contribute to severe tyre wear.

Still no substitute for regularly checking pressures and tyre condition.

TPMS with the more sensitive individual pressure ratings, (whether displayed on screen or not), is a much more accurate 'monitoring' system.

Ham1 · 03-11-2016, 02:29 PM

I think it's compulsory to have TPWS on new cars, to prevent that from happening.

03-11-2016, 01:40 PM	#1
snipnoob86 Major 288 Rep 1,201 Posts Drives: 335D Saloon Join Date: Feb 2015 Location: Manchester iTrader: (0)	Are runflat tyres without tpms dangerous? So, i have just been doing some readin and i came across an interesting story. A lady had RFT's fitted to her car and made generally short journeys. she had a badly damaged tyre, the entire inside edge was blown out and she was only made aware while her car was in for service. The length of time it was damaged for is unknown. Ok, woman driver gaggs, how the hell did she not know. but the fact remains she did not and the car was unable to warn her due to no TPMS. thoughts?
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03-11-2016, 01:59 PM	#2
Chompers Colonel 1155 Rep 2,727 Posts Drives: F31 320d MSport (M) BS /CR Join Date: Mar 2015 Location: Co. Down iTrader: (0)	RFT's have been on BMW's for ages. TPMS is a relatively new addition in terms of giving the tyre pressure at each corner, when a +/-0.2 bar difference between tyres on the same axle is noted by the TPMS an amber warning is given. I will hold my hands up here and now and admit that I suffered the same fate as the woman you mention. The inside edge on one of my rears on my e61 was run down so low that it wires were visible it was shear luck that I found it in this condition, and only because the kids ball went under the car. From that day on I have always checked the rear inside on a regular basis. __________________ Curent: F31 335d xDrive MSport Individual TB / OW Merino Gone: F31 320d MSport BS /CR, E61 520d MSport Bus Ed, E53 X5 V8 Sport
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03-11-2016, 02:17 PM	#3
Peter-K Private 10 Rep 54 Posts Drives: 220d M Sport Join Date: Aug 2014 Location: North Yorkshire (UK) iTrader: (0)	TMPS reports tyre pressure problems. Cars with run flats compare the rotation speeds of each wheel and throw up a dash warning - cross section of a tyre with an exclamation mark. A flat tyre has in effect a smaller diameter so will turn faster.
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03-11-2016, 02:27 PM	#4
HighlandPete Lieutenant General 6659 Rep 15,858 Posts Drives: BMW F11 535i Touring Join Date: Mar 2007 Location: Scotland, Highland Region iTrader: (0)	Users are not supposed to fit run-flat tyres to vehicles without TPMS/TPWS. With the older TPWS (indirect 'warning' system using wheel speed sensors) users are still prone to tyre issues if the system is not reset at pressure changes, or tyre pressures not regularly checked. All tyres can reduce pressure and there is no warning, plus there can be up to a 30% pressure drop before the warning bong sounds, with the indirect TPWS. TPWS can only really warn of a puncture, not slight drops in pressure which can contribute to severe tyre wear. Still no substitute for regularly checking pressures and tyre condition. TPMS with the more sensitive individual pressure ratings, (whether displayed on screen or not), is a much more accurate 'monitoring' system.
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03-11-2016, 02:29 PM	#5
Ham1 Private First Class 27 Rep 107 Posts Drives: N/a Join Date: Feb 2016 Location: Cardiff iTrader: (0)	I think it's compulsory to have TPWS on new cars, to prevent that from happening.
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