[thnsteven]

Hi all,

Hope you are well.

My car is a 2020 M340i x-drive.

Recently, I noticed a very strange finding. I have done nearly 10 long trips, involving long-time motorway drives at 70MPH. So after I have driven long enough on the motorway, the rear right wheel's temperature will rise much higher than the other wheels while the pressure is in line with the other 3 wheels. So far the strange finding happens every time. The same effect also affects the right rear wheel temperature in urban drive but at a lower extent. Below is the illustration:

Before start:
Front wheel: Pressure 2.7; temperature 27

Rear wheel: Pressure 2.7; temperature 27

After motorway drive:
Front-wheel: Pressure 2.8/2.9; temperature 30

Left rear wheel: Pressure 2.8/2.9; temperature 30

Right rear wheel: Pressure 2.8/2.9; temperature 35

I have done wheel alignment and no strange findings. Any idea what is causing it? Other than the temperature difference, the car drives very well.

Many thanks in advance.

[TheKandyman]

IMO, before getting worried about this (if it is something to be worried about), I would verify that the temperature sensor is not faulty. You could use a temperature gun to measure the temperature of the wheels after such a drive. If the wheels are at about the same temperature, then it is more likely that the sensor is faulty.

[bimbom]

There is an apparent inconsistence with these measurement. The temperature changes substantially, but the tire pressure does not. (Pressure is usually very sensitive to the temperature). Thus, it may be a faulty temperature measurement...

In addition to checking the tire temp with an independent measurement, as suggested above, you may want to check the pressure measurement as well (with a manometer).

[Gaviatrix]

I agree, it looks like a faulty sensor on that wheel given your other readings are consistent. I had a similar sort of anomaly on my Land Rover Discovery some years ago and had to have a sensor replaced.

It's actually really interesting how much the temperature affects pressures. When I was towing an offroad camper with the LR in the Australian summer, I used to need to put the rear tyres up by about 10 psi over the recommended full load pressure to maintain an equivalent temperature to the front tyres (noting that was still well under the max psi for the tyre though). I'm sure it helps prevent tyre failures - I did over 140,000 km with not even a puncture.

[thnsteven]

I see now
many thanks to all your advice