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[sjr47]

175x13 C, 97 +standard 16" Cd wheels on car

[Entwood]

Ok, so you have tpms and your doing 50 with a pikey palace. The tyre blows out. Instant flat. How does tpms help?

A slower deflation then yes. See, I think there is more credit being applied to tpms than is reasonable.


I'd use it as a day to day check for performance reasons. I'd be intrigued to see the pressure differences over a cold morning start followed by a run down the motorway at 5am. That sort of thing, if its accurate enough of course.

But the Holy grail against all eventualities...? Nah, don't think so. In conjunction with run flats maybe, but that's mega bucks and brings in other nuisances like ride quality and cracked rims and.... Tram lining.

Edit, Al beat me to it.

It doesn't ... it cannot do anything about an instantaneous blow out.

However, the majority of research appears to indicate that an instantaneous blowout is an extremely rare occurrence, most deflations start somewhat slowly, and then get worse quickly, often then as a blowout as the tyre overheats due to running soft (in a soft tyre the plys actually rub against each other as they pass the "bump" at the bottom every rotation, this friction leads to a rapid heat build up then structual failure), so TPMS "may" give some warning that this is happening either by pressure drop, or by temperature rise.

The main problem with the "pikey palace" scenario is twofold .. 

1) The tyres are usually carrying a higher load than a car .. eg, my 'van is 1600 kgs on 2 tyres .... thats 800Kg/tyre. the car is 2200 kg on 4 tyres . thats 550kg / tyre .. a large load differential so when things go wrong the do so faster.

2) Lack of "feel" ... experienced drivers like yourself can instantly tell if a car tyre is "soft" as the car "feels" different, if front the steering is "just not right" .. if rear it just "feels" wrong through the seat of the pants... this doesn't happen with a trailer of any description, there is no "feel" at all .. so a soft tyre on a 'van just keeps getings worse and you just don't know it...

TPMS has the ability to inform the driver of the state of the trailer wheels in pressure and temperature ... but the reliabilty is still, IMHO, too suspect.... if it doesn't tell the truth all the time .. it may well not provide the very information it is designed to ....

[Marks DTM Calib]

The TPMS setups are actually pretty reliable these days (unless it has a Renault badge!) and if they include temp sensing then all the better.

Reality is that a blowout is normally caused due to heating of the tyre wall due to a slightly flat tyre

[sjr47]

lets look at what can cause a instantanious blow out among the reasons I see are under inflation poor maintanance .incorrect type for purpous, poor tyre construction, belive (Firestone had this problem in USA a few years back) catastrophic damage caused by  large foreign objects theres nothing you can do about the latter two but if you take steps correcting the others then you will vastly reduce the chances of said blowout (god this is turning into a tyre thread) also read in Auto Express TPMS will become compulsory on all new cars soon.

[Entwood]

The TPMS setups are actually pretty reliable these days (unless it has a Renault badge!) and if they include temp sensing then all the better.

Reality is that a blowout is normally caused due to heating of the tyre wall due to a slightly flat tyre

I'm guessing you refer to OEM as fitted to new cars ... the aftermarket add-ons for older cars / caravans seem to have some serious reliability problems from the reading I've done ...

[chrisgixer]

http://www.rockshore.uk.com/tyresure-tyre-pressure-monitoring-system-tpms-1689-p.asp

This is the one I had in mind...?

[Entwood]

http://www.rockshore.uk.com/tyresure-tyre-pressure-monitoring-system-tpms-1689-p.asp

This is the one I had in mind...?

My research indicates the "downside" of those internal types are :

Tyre needs to be removed/refitted to fit .. and change batteries/service if a a fault develops. Most tyre fitters will "try" and tell you you cannot refit as they always change the valve (not true you service the unit itself). Easily damaged by said stupid tyre fitter. Large weight requires offsetting by accurate balancing, but that will be another large weight somewhere else on the rim. Can suffer from a poor signal due to screening effect of the tyre .....

"upsides" .. secure.


Other type is http://www.tyrepal.co.uk

"Downside" more stealable, possibly less accurate, appear to be be less robust.

"upsides" - Light so no balance problems. Easily moved from wheel to wheel. No difficulty changing tyres. Battery easily changed.

TBH, it is the tyrepal "type" that I'm looking at, but they do sem prone to problems... ok .. the manufacturers have a good reputation for sorting out problems ... but if the problem results in no warning when one is needed ....... 

[Kevin Wood]

I think they are a good idea for towing. Having had a tyre failure on a twin axle trailer (slowish deflation - picked up a nail in roadworks) when towing, you rarely get any clue that anything's wrong, and if it saves a sudden failure later....

[sjr47]

Think I have made my mind up to purchase a set and become the Guine pig on here, probably the valve replacement type as the in wheel type seem a pita as Entwood sez if any problems + only lookin to fit for long distance journeys/towing so can easily remove when not required now just researching the most reliable type & contacting said manufacturer regarding extending the system as most seem to come with 4 sensors should be able to get a system for approx £200 and its me burfday soon so anyone wanna buy me a prezzie knows whats on the shopping list 

[Entwood]

Think I have made my mind up to purchase a set and become the Guine pig on here, probably the valve replacement type as the in wheel type seem a pita as Entwood sez if any problems + only lookin to fit for long distance journeys/towing so can easily remove when not required now just researching the most reliable type & contacting said manufacturer regarding extending the system as most seem to come with 4 sensors should be able to get a system for approx £200 and its me burfday soon so anyone wanna buy me a prezzie knows whats on the shopping list 

Tyrepal 6 wheel setup  £265.00

http://www.tyrepal.co.uk/products/caravan-and-motorhome-tyre-pressure-monitor

[Auto Addict]

Think I have made my mind up to purchase a set and become the Guine pig on here, probably the valve replacement type as the in wheel type seem a pita as Entwood sez if any problems + only lookin to fit for long distance journeys/towing so can easily remove when not required now just researching the most reliable type & contacting said manufacturer regarding extending the system as most seem to come with 4 sensors should be able to get a system for approx £200 and its me burfday soon so anyone wanna buy me a prezzie knows whats on the shopping list 

Tyrepal 6 wheel setup  £265.00

http://www.tyrepal.co.uk/products/caravan-and-motorhome-tyre-pressure-monitor

I notice  they do a can-bus system, as the Insignia has tyre pressure monitors, I wonder if the caravan could be added to the system.

[chrisgixer]

Is the insignia on run flats AA?

[Phil]

I'm now on my 2nd car with factory fit TPMS and have to say it is vey good.

The only real issues I had previously is the sensors only last 7-10 years so I was getting an 'odd' failure. Occasionally it would say sudden loss of pressure to nearside front, but after few yards would be fine again. New sensors solved the problem.

If you use run flats you HAVE to have TPMS fitted. Tyre place should refuse to fit unless you do as its very difficult to tell (on a car anyway) if the tyre has lost considerable pressure

[chrisgixer]

Yes brother in law has tpms and run flats on his Beemer(Spit).

Didn't understand the true meaning of the dash warning, and as the car drove ok he continued on his way across Europe. Until the tyre eventually disintegrated of course.

Oh sigh....

Having driven the car though, if you think omegas feed back through the steering a lot, try run flats. Horrid.

[05omegav6]

I know a chap who had a 530d tourer... he had a pressure warning come up which he ignored, and on the way back from Heathrow one day felt a bit of a shimmy as he joined the M25. Two days later got the tyre checked and found two inches of tread missding from the inside edge

Apparently no change to the cars behaviour