Re: Kumho tire pressures

["Gary Derian" <gderian@xxxxxxxxxxxx>]

Tire temperatures are a good piece of information and even temperatures are
a good goal to have but what really matters is your lap time.  Car setup is
too complex and full of compromises, especially road cars, to make such
absolute statements.

Radial tires will not necessarily heat up in the center of the tread if the
air pressure in increased.  High inflation does not make a radial tire
"round out".  It, in fact, will flatten the tread.  This is because the
sidewalls stretch a bit but the belts keep the tread in place.

Gary Derian <gderian@domain.elided>
>
> The only way to determine proper tire pressures and alignment is to use a
> pyrometer (preferably the needle type). Immediately, after your last hot
lap,
> and preferably before your cool down lap, take the tire contact patch
> temperatures on each tire at the following locations: one inch from the
inner
> edge, center and one inch from the outer edge.
>
> If each tire temps are within 5 degrees F, then the tire pressure and
alignment
> is perfect. This is the BEST traction situation.
> If the middle temp is the highest, the tire is over-inflated.
> If the middle temp is the lowest, the tire is under-inflated.
> If the temps get higher, in a linear fashion, from the inside tire edge to
the
> outside, tire pressure is OK but you have too little camber.
> If the temps get lower, in a linear fashion, from the inside tire edge to
the
> outside, tire pressure is OK but you have too much camber.
>
> You can also determine which tire gets the most abuse, i.e. has the
hottest
> temps, and rotate it accordingly.
> Pyrometers are a GREAT investment for under $200...
>
> Take care,
> Theo.
> '97 M3 (46 HS)
>
>

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