UK Karting - Notice Board (General Karting) : Re: tyre temps

Notice Board (General Karting)

Re: tyre temps
Posted by 'SimonS' on 14 Mar 2011 @ 10:48

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SimonSJoined: December 2004
Total Posts: 4
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tyres grip by a mix of mechanical grip, the friction between rubber and road, and chemical grip, the 'stickiness' of the tyre at certain temperatures.

Tyre pressure controls the tyre shape and the amount of flex in the carcase. The flex also induces heat. Tyre shape controls mechanical grip.

Tyre Temperature increases chemical grip up to a certain optimum temperature, thought to be about 65C in kart tyres, though other race tyres operate at up to 100C.

Very roughly, the increase in heat (in degrees Kelvin)in a tyre is proportional to the increase in tyre pressure.

So, if you measure tyre temperature and pressure on the dummy grid as 10C (283K) and 1 bar, and the kart comes in with a pressure of 1.2 bar (an increase of 20%) after the event, then the tyre temperature will have been raised 20% as well (56 degrees K) and the tyre temperature will have been around 66C, near enough the optimum.

For most people the loss of mechanical grip from the wrong pressure is more serious than the loss of chemical grip from the wrong temperature. One can go out on cold tyres at the 'right' pressure and get much closer to an optimum time than one can go out on hot tyres at the wrong pressure for a single lap.

However most races are longer than one lap, so one sets the tyre pressure below optimum so that it is optimum when the race is in progress.

So that's why most pit crews only measure pressure, it is more important than temperature and the two are inextricably linked.

This isn't to say that temperature isn't important. But you can't do much about the temeprature, you can alter the pressures.

HTH

Message Thread:

tyre temps by 'fatboynobby' (13 Mar 2011 @ 22:08)

Re: tyre temps by 'AndyOxfordshire' (14 Mar 2011 @ 8:28)

Re: tyre temps by 'SimonS' << You are here!

re: tyre pressures by 'fatboynobby' (14 Mar 2011 @ 13:29)

re: tyre pressures by 'mattman' (14 Mar 2011 @ 13:56)

re: tyre pressures by 'AndyOxfordshire' (14 Mar 2011 @ 14:23)

re: tyre pressures by 'mattman' (14 Mar 2011 @ 14:53)

re: tyre pressures by 'AndyOxfordshire' (14 Mar 2011 @ 16:23)

re: tyre pressures by 'davidmc' (14 Mar 2011 @ 20:26)

re: tyre pressures by 'SimonS' (15 Mar 2011 @ 16:19)

re: tyre pressures by 'mattman' (17 Mar 2011 @ 12:17)

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