-2C or -12C...What's the difference?

[TripleS]

It is only during the last few years that I've had a car with an outside temperature indicator, and although I welcome the device I don't feel it adds much of great practical value for me. I'd already spent a great many years learning to judge road surfaces by appearance, and by changes in how the car feels and sounds, and I still work mainly on that basis.

Best wishes all,
Dave.

Luddite

I suppose you drive with the side window cracked open so you can hear if the tyres suddenly go quiet?

That is scary

The 'Luddite' bit may be partially justified; the rest is not.

A change in feel and (to some extent) noise level can be detected without windows being open if you are reasonably sensitive to these sources of information. again.

Best wishes all,
Dave.

[7db]

There is always some slip. Although the level of grip between tyres and a road is excellent it is not perfect and there will always be some slip albeit at a level that is imperceptible to the driver or any observers.

Hmmm. You'll forgive me for believing that something which is imperceptible doesn't exist.

I have wondered how much heat transfer there is. When you see cars in thermal imaging cameras from helicopters there is quite a visible (although short lived) hot trail left on the road from the wheels.

Why do you assume the heating is from heat transfer, not an adiabatic process?

[TripleS]

There is always some slip. Although the level of grip between tyres and a road is excellent it is not perfect and there will always be some slip albeit at a level that is imperceptible to the driver or any observers.

Hmmm. You'll forgive me for believing that something which is imperceptible doesn't exist.

It might exist, but if it is imperceptible we can't prove that it does; er, I think that's right.

Best wishes all,
Dave.