I tried sending this on the 4th and it didn't make it to the list. Possibly
because I didn't delete the previous emails that led to my comments but
probably due to the switch from AT&T to Comcast on my internet address.
Here's another try.
Wes
----------
From: W S Potter <wester6935@comcast.net>
Date: Fri, 04 Jul 2003 12:08:35 -0600
To: Glenn Ridlen <gridlen@yahoo.com>, Russel Mack <rtmack@concentric.net>,
gary baker <lsr350@hotmail.com>, <land-speed@autox.team.net>
Subject: Re: tire test
Firestone provided tires for all of the endurance attempts by Ab Jenkins
from the thirties until his death in 1956. He ran for 24 hours on many of
those attempts. Speeds increased from the mid 140's to over 195 mph for a
full hour. One constant comment that Firestone engineers made over the
years was that tire wear was not a problem at Bonneville. The salt is
naturally cool from the constant evaporation of the brine percolating
through to the salt surface. When they made the Bonneville land-speed tires
in the late fifties they made them with very little tread because of their
assumption from their experience on the salt that tire wear wasn't a factor.
They did design the tires with cord wrappings with a very high angle, almost
90 degrees from the bead in some of the wraps. They must have assumed that
any heat would be from sidewall flex. It's my assumption from what I read
that their greatest concern was centrifugal force. That's the reason for
using high tire pressures and little tread on the tires. All of that was
before the current radial tire technology was in use.
I'm just speculating again here but the spin test they ran in Montana may be
a very valid test and the most important one for high speed runs on the
salt. Centrifugal tire growth due to sidewall wrapping flex and the
resulting heat build up may just be the greatest danger for very high speed
running.
The heat from tire spin is obviously another factor ... when you can follow
a fast streamliners tracks in the salt for miles they certainly have a
problem with traction. Perhaps this is where traction control has a place
in this kind of racing. I remember articles in magazines by automotive
engineers that stated authoritatively that a terminal 147 MPH was the
fastest speed a dragster would be able to reach. Then some hot rodder
proved them wrong.
Wes
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