Tyre Pressure indicator. Gimmick?????

[VWindahouse]

what happened?? audible sound or just the light. do you remember the tyre pressure difference.

Same as the low fuel warning. From memory it was about 4-5 psi less than what I set it at.

[Timbo]

Silly question but needs to be asked... had you actually set the tyre pressure indicator to begin with ?

Not sure who this was directed at, but in my case I usually reset the indicator after checking and re-inflating tyres -- just forgot after having new wheels/tyres fitted

[shaneth]

Silly question but needs to be asked... had you actually set the tyre pressure indicator to begin with ?

How dare you........ Yeah mate i reset it everytime i change tyre pressures. or even check them.

[Glide_GTI]

to answer a few questions here, I spoke to derek about the sensor, heres how it works.


its actually a part of the ABS system, it detects the 'pressure' by measuring the rotation speed of each tire, so when you get a flat, it will notice a change in the rotation speed compared to the other three, if you get a flat in all 4 at once, it wont be able to detect pressure drops

[FL00DY]

I've had it come on before, checked all pressures and one had gone down so I pumped it up. Few days later it went on again. Same tyre was low on pressure, changed the tyre with the spare. Went to my tyre guy for him to inspect the deflating tyre and he found a screw in it. Removed the screw, repaired the hole and it was fine after that. If I didn't have the pressure light, I would have been driving it till it was flat and been changing the tyre on the side of the road.

The only other time it's come on was after my new wheels got put on and I hadn't reset the indicator.

[beefa]

Based on the way it works, as mentioned above, you would have to assume that the wheel requires a given number of rotations for the sensor to be able to accurately measure the difference in the rolling diametre of the tyre. So a blow out or very rapid deflation may not allow you to drive far enough (hence enough rotations) for the computer to calculate there is a difference.

[pinzvidz]

I blew my tyre and it never went off. I did forget to reset it once i had the new one on there. And it went off.

Hmmm... I suspect the system has a very slow refresh rate, rather like a fuel gauge. Think of it this way - a fuel gauge with a real time connection to the potentiometer in the tank would swing all over the place whilst you're going around corners, braking etc. Usually fuel gauges update every 10 or 15 seconds so you don't see the wild swinging about. The same might apply to the tyre pressure sensors - maybe they only update every so often. So if suddenly you blew a tyre whilst driving, it wouldn't set off the warning. A slow leak, however, would be a different story.

[FL00DY]

Hmmm... I suspect the system has a very slow refresh rate, rather like a fuel gauge. Think of it this way - a fuel gauge with a real time connection to the potentiometer in the tank would swing all over the place whilst you're going around corners, braking etc. Usually fuel gauges update every 10 or 15 seconds so you don't see the wild swinging about. The same might apply to the tyre pressure sensors - maybe they only update every so often. So if suddenly you blew a tyre whilst driving, it wouldn't set off the warning. A slow leak, however, would be a different story.

lol yeh but surely this is more because you don't need a pressure monitor to tell you about a blow out You can feel that, a slow leak you can't feel and gives you time, in my story ^^^^^ for instance, to work out what wheel it is and if it's a problem with the tyre itself.

[PoloGTi]

Mine has worked every time the tyre has droped around 8psi or more i had a slow leek in a front tyre and every time i pumped it up and then when it went down 8psi it went off again. Also worked when i rolled a tyre off a rim and when i put the spear on it went off again after restetting. Why not drop 10psi out of a tyre drive down the street see if it comes on? After all nothing beats a good tyre gauge and then you know its going to be all good.

[Timbo]

I can happily report again that mine works. On the drive to work yesterday, it came on. So I stopped and checked the tyres. All 'appeared' OK but when I checked more carefully using a tyre gauge I found the right rear had 10psi. Nail!