john,
i run those low pressures for 1/2 hour to 1 hour road races. the vehicle
weight is so light the vintage race tires have next to no contact patch if
i run higher presures. the nose of the sports racer is so light i can pick
it up and literally carry it !
i'm running 5.00-15 tires and considering going down to 4.50-15's on the
car. i'm able to run with lister jaguar specials. those darn cars are
fast-fast-fast! and, i'm lighter and able to late brake into corners in
spite of 4 wheel drum brakes! john , you've got as bigger brass set of
(them) than i do! i have no desire to run open wheeled cars! my father
was the same way in that respect.
but! my vintage H-mod sports racer is as close as you can get to driving a
formula car! seriously . i tip my hat to you in the formula car! at over
6' tall there are few formula cars i could fit into. but , i'd love a few
laps to see what it's like from you'r point of view....
chuck
> [Original Message]
> From: John D. Caffrey <jdc6@Lehigh.EDU>
> To: <cfchrist@earthlink.net>
> Cc: <spridgets@autox.team.net>
> Date: 8/26/2006 7:45:28 AM
> Subject: Re: Helium in Tires
>
> FVee weight is close to your sports racer at 825 Lbs. Do you run those
> low pressures for hillclimbs and the longer vintage races? I'm sure
> that is what feels best, but maybe it's because of the treaded tires
> with sidewalls that are a bit too stiff for the weight? I wouldn't be
> able to keep the tires on the rims at 10 psi, and the car wallows
> around too much at 15 psi cold pressure. I will occasionally start at
> 17F/19R when the track is green, like on a test day, so the car will
> respond slower and the tires will build heat quicker. Normal starting
> pressures of 20 psi give the fastest response and the car is more
> stable, and we always stop in the pits after the session to check em
> hot, and then we can fine tune the cold pressure for the next session.
> When I raced the Sprite on 20x8-13 GY cantilever slicks, the ideal
> pressures were the exactly same.
>
> Are you going to Macungie for the street rod show?
> John
>
>
> Charles Christ wrote:
|