On 23/06/2018 07:41, The Natural Philosopher wrote:


I am notr syoing it doesn't work, just that it relies on some pretty
iffy interpreation of very small differences in road speed.


It seems to work fine on my Audi. It tells me if there is a problem with
a single tyre or to check all tyres. It detects tyre pressures which are
different to what was saved, you need to tell the car the tyres are at
the correct pressures.

I've seen it detect something is wrong with all tyres. This was after
rotating the tyres front to back and failing to reset the pressures
monitor. The fronts are run at 38-40PSI and the rears at 32-34PSI. It
chimed after about 1/2mile that I should check all 4 tyres.

It detects rotational rate not expected due to pressure change, either
under or over inflation. I had a persistent slow. It turns out the
alloy's painted surface where the bead meets the wheel was corroded and
leaking. My local tyre place cleaned and painted this and the tyre was
fine since. However, they pumped up the tyre hard during checking and
didn't set the correct pressure. About 2miles after driving the check
tyre chime went off. The screen said check pressure and it shows a flat
tyre but it was over inflated in this case. The system detected it was
rotating at the wrong rate for what was set. It doesn't have an over
inflated graphic!

A pressure sender would give an instant out of range indication but this
system has never failed to warn me of issues I'd not notice from driving
immediately.