it''s a game like nascar 4.

i have tire load (including the weight transfer), rate of rotation of the tire, and the slickness of the tire (due to wear and road surface) worked into the equation, but not the friction factor (which i do feel is an important part of it, because tires heat up when you brake and skid the tires against the road).

so far, johnb''s function works best because it takes into acct heating, cooling, and not exceeding the lower limit of the atmospheric temperature.

a2k

The next time I run into one of my buddies I''ll ask them (most of them are automotive engineers, and one if them works with tires).

If I remember correctly, an average automobile''s tires heat up to about 150F on the freeway (or was it 250F...).

Anyway, the first thing they teach you in automotive engineering is to take any theory you have and toss it, ''cause it''s oh-so-rarely accurate. You need empirical data, and models based on that data.

The problem of dynamicly determining tire temperature is far more complicated than just plugging in the coef. of friction and speed. There''s force convection involved, which means the friggin'' temperature and humidty of the air matters. Alot.

Braking will affect the tire temperature, eventually. How much and how fast are the hard questions to answer. If a vechicle brakes too much for too long you can boil your brake fluid... or glass-over your brake bads (the material the brakes are made out of lose effectiveness (frictional forces) as the temperature increases, critical so at a high enough temp. which of course depends on the brake).

In short, if you want to know how a tire behaves; you have to test it and collect data on _that type of tire. If the manufactoring processes are consistent, all tires of that type will perform likewise. If you want to know how tires in general behave, you have to collect and analyze data on a pile of different tires.

General newtonian physics just doesn''t correlate the the real world very well. There''s too many assumptions made to make the math easier, that don''t hold true.

PS I write software to test brakes for a living.

Magmai Kai Holmlor
- The disgruntled & disillusioned

yes, i''ve also worked in convection, but a fake one based on the rate of rotation of the tire. it works okay for now. my "data collection and analysis" has only consisted of studying nascar racing 4 tire temps, and that''s about as far as i''ll go with analysis, other than other formulas that other people may have. thanks for the help guys, keep the ideas coming...

a2k