Gen 4 Tyre Pressure

Dorsetdumpling wrote: My experience of basic TPMS is that you inflate your tyres to the right pressures, then reset the system.

You therefore “tell it” what the pressures should be.

The system will then warn if tyre pressures drop below this initial setting beyond a defined margin.

More sophisticated versions will show the actual pressures on the instrument panel display.

You can see the actual psi on the screen if you go through the menu once the wheels have rotated a few times. They were showing 38, now 26 without showing an alert. So I can presume the monitor weren't set at the higher pressure.

TaterTot wrote: I've only seen basic ones that trigger on lowered pressure. And I would guess it's like that, because the pressure won't naturally increase in a tire, on the road. Well, unless it gets really hot that is.

The ones that show the actual tyre pressure are quite informative, as you drive from cold you can watch the tyre pressures rise quite a significant amount even during normal driving.

I think that there was one version of ‘TPMS’ that worked by using the ABS sensors on each wheel to compare the rates at which the wheels were turning relative to each other. The idea was that if a tyre was running flat, that wheel’s diameter would be effectively reduced, and it would be going round faster than the others.

Oh sure. Wonder how many weird ways one could actually measure that stuff, by using other systems.

But the thing I tried to say was about the basic ones. They are pretty simple, but they do what they should.

I took apart the Jimny TPMS and install aftermarket one that shows TEMP and PSI of each tire. Better in my opinion.

new cooper at3 s yesterday, garage put 30psi in all bounced everywhere, got home at put the norm 23 front 27 rear

The garage needs a serious rebuke for that - my neighbour almost came off the road because a garage over inflated the tyres on hers