Hi all

Got 60 plate VRS with pressure monitors but since owning the car nearly a year they haven't gone of once or warned me as checked pressure few times and been low....

Just bit of advice is it a case only work when flat or rapid deflation

How low were they? I've found you need to drop around 0.5 bar before it registers. The system uses the ABS to detect a difference in the speed of rotation of one wheel compared to the others.

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How low were they? I've found you need to drop around 0.5 bar before it registers. The system uses the ABS to detect a difference in the speed of rotation of one wheel compared to the others.

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That's what I thought no I mean down to 20psi trouble is my car might not get used for week or two but still nothing comes up...is monitor in the valve or do they just use standard valves

Because it uses ABS you need to drive far enough for the speed difference to show up. If you only drove a short distance and relatively slowly it may not register.

As I said there are no special valves it just uses the sensors in the hubs for the ABS.

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Yup

It's not really a tyre pressure monitoring system, more a "does a tyre seem to be smaller than expected" system.

That's why the tyre pressure warning light is one of the ones which comes on when an ABS sensor or bearing fails, like 2 years ago when I collected my brand new Octavia and was 5 minutes down the road doing 50mph when half the warning lights came on at once

Similar thread on the Superb forum. I concluded that you could drive 3 miles or more on a soft tyre before it would notice. May trigger more reliably for tyre deflation when on a run I guess.

 

http://www.briskoda.net/forums/topic/341258-tyre-pressure-warning-system-not-convinced/

How low were they? I've found you need to drop around 0.5 bar before it registers. The system uses the ABS to detect a difference in the speed of rotation of one wheel compared to the others.

Sent from my Nexus 4 using Tapatalk

  

Similar thread on the Superb forum. I concluded that you could drive 3 miles or more on a soft tyre before it would notice. May trigger more reliably for tyre deflation when on a run I guess.

 

http://www.briskoda.net/forums/topic/341258-tyre-pressure-warning-system-not-convinced/

  

Yup

It's not really a tyre pressure monitoring system, more a "does a tyre seem to be smaller than expected" system.

That's why the tyre pressure warning light is one of the ones which comes on when an ABS sensor or bearing fails, like 2 years ago when I collected my brand new Octavia and was 5 minutes down the road doing 50mph when half the warning lights came on at once

  

Because it uses ABS you need to drive far enough for the speed difference to show up. If you only drove a short distance and relatively slowly it may not register.

As I said there are no special valves it just uses the sensors in the hubs for the ABS.

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OK that kind of makes sense the only time my wife remember it coming on was when we had the wheels refurbished since then they never have even driving to garage to pump them up very strange

it based on relative measurements. 

i.e., is one of the tyres rotating at a different speed to the others?  usually a tyre at lower pressure will do that.

 

however, if ALL 4 tyres drop at the same rate, then they're all still rotating at the "same speed", hence no alarm bells are raised. 

hence, all tyres could've dropped to say 26 psi, and the monitor won't trigger.

 

i believe it works out to be 5 psi or more before the difference in rotational speed becomes significant enough to notified.

You need to reset it every time you top up the tyres.

 

It only goes off if one tyre is low compared to the others.

it based on relative measurements. 

i.e., is one of the tyres rotating at a different speed to the others?  usually a tyre at lower pressure will do that.

 

however, if ALL 4 tyres drop at the same rate, then they're all still rotating at the "same speed", hence no alarm bells are raised. 

hence, all tyres could've dropped to say 26 psi, and the monitor won't trigger.

Not necessarily, since it also knows the output speed of the gearbox and can measure all four wheels for changes against that.

Backing up what others have said, I hit a pothole with my front near side wheel and it caused a fast puncture/deflation.  The monitor did not go off but I knew I had a problem and stopped within 1/2 mile.

Backing up what others have said, I hit a pothole with my front near side wheel and it caused a fast puncture/deflation.  The monitor did not go off but I knew I had a problem and stopped within 1/2 mile.

That's crazy what's the point in the system if doesn't go off

That's crazy what's the point in the system if doesn't go off

That's not what the system is designed to do! If you don't notice a total flat tyre then there is something wrong.

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Treat it as an extra and don't rely on it. It's not that good.

 

You still need to do your normal tyre checks

The only time it has been needed on our octy, it didn't give a warning until after the wheel was changed, even though the issue was a reasonably rapid deflation at 30mph. Large screw right on the outside edge of the tread, so not repairable anyway, but that's not the point.

If, as said above, it warns when the pressure drops by 0.5 bar, you would have thought it would in these circumstances.

I'm glad the TPM came as a free option, because I reckon its next to useless.

You shouldnt rely on electrical systems to tell you if your tyre is loosing pressure. Thats general maintanence of owning a car.

I had a new tyre last weekend but as the car wasnt driven much over the last week the light only came on yesterday when i wss on the motorway so it needs time to realise the differences

Picked my Octavia VRS up last Monday and it was fine.  After about 100 plus miles on Tuesday the light came on.  The car was driving properly and I didn't think there was a problem however I still stopped and did a visual check that confirmed what I thought.  Once I arrived at my destination a few minutes later I let the tyres cool down and checked the pressures and they were all bang on.  So I assume that the wheels had been off when the car was serviced and it had only just woke up.

 

As others have said though it is there as an extra tool and regular checks of tyre pressures should still be a part of owning a car.  How many minutes does it take when you are washing the car to check the tyres?  Even easier how many seconds does it take to do a visual check before driving?  Electronics can make life easier but it also has a habit of making us lazy by relying on it and then when it lets us down we only have ourselves to blame.

 

Regards Chris

I check the tyre pressures every weekend, along with oil, water, screen wash etc.

And agree, it is only an additional tool, but the fact remains it didn't work as Immediately as I would expect in the situation we encountered.

Mine went off this morning on my way to work about one mile from home. Got out and immediately noticed a screw sticking out the shoulder of the OSR tyre. You could hear the air hissing out so it mist have happened as I left home.

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I use this system;

www.tyrepal.co.uk/tyre-pressure-monitoring-system-applications/tpms-for-cars

Easily transferable, easy to install and fairly accurate. It works on the loss of pressure, not tyre rotation as with the OEM system.

Of the two punctures I have suffered since installation it picked up one, but as the other one was airtight and therefore not leaking air, the system didn't trigger.

I check the condition of the tyres when cleaning the car, normally once or twice a week, and unless the system indicates a noticeable drop in pressure, I top up the tyres at the beginning of each month.

Fin