Hello Ed,
Tire frontal area is a really big issue at any speed as drag increases
greatly with increase in speed and the Cd is relatively high.......but how
about considering this......the top of the tire is moving twice as fast as
the car, relative to the wind, and the bottom of the tire is not moving at
all relative to the wind (no slippage). So if you cover the top of the
tire, most of the skin drag would be eliminated? Here's one to calculate,
Mayf. The desired answer might be "How much of the tire to cover?" or what
is the real drag of an open tire?
The top of our tires were going 542 MPH at the "5". The top of Law's tires
were going 700 MPH. Hammond's at 600. I wonder what sonic shock waves will
do to tire tread...or.....how narrow a tire can we use and still be safe
from excessive distortion? Seems we had a thread about flexing some months
ago......wonder what happened? I seem to remember some sensitivity about
it.....
Skip (One would think that I have enough to do.....)
At 10:44 AM 3/2/02 -0700, you wrote:
>One thing I have learned in LSR is that there are no
>absolutes. Your rain tires worked well on your car, but would
>they have done the job on a roadster? Prollly not, based on
>opinions/experience from other racers. When I referred to
>treaded tires, I meant FULL tread (like street tires) not
>grooved tires. While I don't understand all the physics
>involved, I know from experience that they won't as well as a
>treadless tire (and Joe did understand what I was trying to
>say about treads leaving more exposed areas of rubber) Look
>on the back of my Vette & you will see 7" Short-track tires
>with 3 wide, deep grooves running the circumfrence. I would
>have preferred slicks, but Mr. Goodyear doesn't make my
>application in a treadless design. I know when I tow to the
>line, the grooves pack with salt. Do they clean themselves out
>at speed? I don't know, been too busy to look back there & see
>if my tires are clean ;-) If the grooves do stay "open" I
>would guess that it would be a factor in directional
>stability. BTW Mayf, I haven't seen section width running
>through your calculation either. That is prolly because nobody
>considers it important, but to me it is an aero issue.....
>ed (yeah, I know I am rambling again........)
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