In a message dated 5/7/00 12:11:29 AM Eastern Daylight Time,
woods@mae.uta.edu writes:
> I would like to share with you another number that we have found by
> plotting the average g's (average of the g-vector from the start to the
> finish of an autocross). The correlation is quite good and shows that an
> increase in 0.1 g's average results in 3.0 seconds on a 60-second course.
> This 0.1 g's can come from driver ability or from the tires. Further,
> tires drop by 0.1 to 0.2 g's as they wear from new to about 25% of the wear
> indicators left (I'm referring to racing slicks on a Formula SAE car).
Those are some interesting numbers. So at that point you are 3.0 or more
seconds slower on a 60-second course compared to new tires? How many
runs does it take to wear the slicks you're using down that much?
I've always felt that R-compound DOT tires lose a certain amount of grip
toward
the very end of their life, but always thought it was mainly due to heat
cycling.
And I never felt that the drop-off in time was anything near that amount,
although
I've never tried to quantify it myself.
GH
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