Tyre temps.

Guys, Some time last year I asked about real racing tyres, and how the tyre pressure would influence their running temperature. (I know it's slightly off topic, but it does apply to some sims where you can adjust this, any anyway, this is the best place to have a discussion like this, 'cause there's a lot of knowledge in here). Anyhow, someone managed to convince me that increasing the tyre pressure would reduce the tyre temperature. Since than I have experimented with real kart racing tyres on a kart, and found the opposite to be true. The lowest pressure you can get away with, with my kart is about 15psi, any lower and you risk it coming off. The highest is 60psi as marked on the tyre. I started at 15 psi, and found that the handling was very heavy, and not too accurate, as the tyres were very soft. I then gradually increased the pressure, and found that the tyre was noticeably hotter when I got to 20psi, and each time, I had more grip. Obviously, you get to a point where the contact patch starts to reduce in size, and you get less grip, a hotter middle, and cooler edges. I just thought I'd share this observation with you all. R.

On Fri, 21 Feb 2003 14:50:18 -0000, "Richard S Beckett" <[email hidden]> wrote:

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>Guys, > >Some time last year I asked about real racing tyres, and how the tyre >pressure would influence their running temperature. (I know it's slightly >off topic, but it does apply to some sims where you can adjust this, any >anyway, this is the best place to have a discussion like this, 'cause >there's a lot of knowledge in here). > >Anyhow, someone managed to convince me that increasing the tyre pressure >would reduce the tyre temperature.

You'd expect some kind of curve; low temps with low pressure, higher temps as the pressure makes the contact patch flat, and lower temps again when you overdo the pressure.

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>The lowest pressure you can get away with, with my kart is about 15psi, any >lower and you risk it coming off. The highest is 60psi as marked on the >tyre. I started at 15 psi, and found that the handling was very heavy, and >not too accurate, as the tyres were very soft. > >I then gradually increased the pressure, and found that the tyre was >noticeably hotter when I got to 20psi, and each time, I had more grip.

More grip though means more heat, so because of the better grip you might have generated more heat, but not more heat per Newton of grip. In other words, there are multiple effects, that are pushing/pulling the tire to warmer & colder. More grip means you'll get better G-forces, but this means that more energy is involved, so a warmer tire. Given 2 runs with a 15psi and a 20psi tire, requiring to turn every corner with the same G-forces, it might be that the 15psi tire must work harder and get warmer nevertheless. You just might not have come this far though, as the 20psi is then just faster/better. Hope this is a bit clear. ;-) I just mean it's difficult to see what is doing what, as you'll (be able to) drive differently as well with different tire pressures. Ruud van Gaal Free car sim: http://www.racer.nl/ Pencil art : http://www.marketgraph.nl/gallery/