List,
It was not uncommon in the first few years at the salt to see cars running
street tires that lost a tread at 120 mph speeds. Firestone, through their
experience with the Ab Jenkins record attempts, had some experience with the
salt and tire needs. They had a tent with specialty tires for sale at a
fair price, a crew to mount and balance them and align the front suspension
on the spot. The man who was their Bonneville representative later died of
skin cancer from his unprotected sunburns year after year.
The premise for the Firestone Bonneville tire was that the cord went from
bead to bead at a very low angle so there could be minimal stretching and
deflection at high centrifugal forces. This also made for a heavier
sidewall. The rubber covering was more of a gum dip than an actual tread
since their endurance experience on the salt indicated very low tire tread
wear.
We don't see manufacturers on the salt today. I suspect the greatest
deterrent is the legal problems we are so familiar with today. Al Teague
has combed the world for Firestone Bonneville tires last made in the sixties
and runs on them at 400+ mph speeds. Mickey Thompson "leases" their tires
for five years to help control obsolete tires and damaged tires being used
at these incredible speeds.
As wider tires and racing radial tires with better technology came along the
reason for their being was speedway and sports car racing involving turns
... which necessitate lighter sidewalls and better footprints for high
speed control on turns. The aspect ratio and tread depth has increased with
that demand. You have all seen the tires that have been shaved to get rid
of that excess tread so it would not come off at speed. Motorcycle
streamliners etc. are the biggest advocates of this practice.
Centrifugal force/tread weight, rolling resistance/heat and wind resistance
are the greatest reasons to run narrower tires on the salt if you subscribe
to those earlier premises of tire construction.
Remember the red Ford GT40 that went over a couple of years ago with the fat
tires?
Wes
----------
> From: "Thomas E. Bryant" <saltracer@awwwsome.com>
> To: David Haller <dhaller@techline.com>
> Subject: Re: Tires
> Date: Wed, 10 Nov 1999 09:35:12 -0800
>
>Group,
>
>This tire discussion is good for all. As has been mentioned, tires
>produced for our type racing is becoming more critical each year.
>
>The idea that a wide tire won't work at Bonneville has been around for a
>long time. In the 50's and 60's there were lots of Indy take-offs that
>fit our purpose well, and at a low price. These tires, especially the
>fronts, presented a narrow contact with the ground and worked very well
>under most all conditions.
>
>The first car that I remember that ran a wide tire was Tom McMullens
>street roadster. This was in the early 60's. Subsequently others have
>tried the wider tire with varied success. In my opinion, the reason that
>the wider tire got a bad rap was because the cars they were tried on had
>handling problems that were magnified, and when the surface is wet (even
>with a great course, as the day heats up water comes to the surface) the
>wider tire tends to hydroplane. In the thinking of the early days, the
>tires that nearly all of us run now would have been consider wide
>tires.
>
>Tom
>
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