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Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 12:06 am
by MadMark
Isn't the car susceptible to tyre pressures?
When I first got mine, the drive on the way home felt slightly odd under heavy braking and perhaps not as precise as I was expecting as it kept pitching left. I think the previous owner hadn't used it in a while and may not have checked them as he was selling the car, plus the rear right valve was wound too tight to take a reading initially (soon loosened off a quarter turn).
They read as:
Front L - 33.5
Front R - 34.0
Rear L - 35.0
Rear R - 38.0
Now all changed to 38F and 35R - it's like a different car!

Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 11:20 am
by CusterDome
I'm surprised your tyre pressure sensor didn't light up. Did you get the option on your dash to reset it when you altered the pressures?
Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 11:41 am
by G30001
Low profile tyres.
When you nail tyre pressures the car is so different.
this time of year is worse as the temps are all over the place as like Autum, could be previous owner had done the tyres in the depths of Winter
Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 1:36 pm
by Rusty Racer
Agreed, with such a heavy lump up front it’s a good idea to check regularly (of course we all do anyway!)
If you kept resetting the TP warning as the pressures vary it will defeat the object of having it - no great science behind it the ESP looks for crabbing iirc
Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 1:44 pm
by MadMark
CusterDome wrote: ↑Tue Mar 02, 2021 11:20 am
I'm surprised your tyre pressure sensor didn't light up. Did you get the option on your dash to reset it when you altered the pressures?
I was surprised it didn't set off the sensor - but my run home was mostly motorway, so the pressures would have been up anyway. Testing them cold the following day was deliberate and I reset the pressure sensor reset straight away by delving into the menus!
I'm pretty good with checking mine at least every month if not sooner.
Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 1:45 pm
by CusterDome
I've never had to reset my TP warnings except when there's been an obvious change in pressure, - puncture, new tyre etc. I'd assume that it's not that sensitive to put up a warning with normal day to day changes, the 4psi change that MM made must be within its trigger range.
Re: Tyre pressures! So sensitive to changes ...
Posted: Tue Mar 02, 2021 4:08 pm
by MadMark
Unlike the pressure sensors in the BMW M and Porsche ranges, these don't measure real time pressure and temperature, which is really useful in the real world. These are much more basic and I understand only trigger with something over a 25% pressure drop on one or more tyres (approx. 9psi). However, if all 4 tyres are equally low, it doesn't register the pressure drop!
Re: Tyre pressures! So sensitive to changes ...
Posted: Thu Mar 04, 2021 1:01 pm
by Rusty Racer
Wheels use a standard valve and it’s all done through the ESP I believe