At the risk of seeming just argumentative, Hoosier, and most other
manufacturers, don't really publish a starting pressure for racing tires,
that's usually tire resellers. And the numbers I've seen for Hoosier A6/R6 are
pretty much the same numbers I've seen for TDs and Speedster tires: For an
1800-2200 pound car its 26-31 cold. Note that it's a really big cold range.
Peyote is about 1580 wet and with Speedsters I've settled in at 23.5# all the
way around with a bit of fiddling depending on how hot I think the track is
going to be. Depending on the track and the day that translates to 32# hot. If
there's a reason to experiment we get a bunch of tire temps, find a HOT
pressure that yields a center temp close to the inside and outside edge temps
on all four tires, let it cool down overnight and read the cold temperature on
each. Most production cars will yield a different value for the front and
rear, and to a lesser degree side to side, mostly because of weight
distribution. You write those down and that's your cold pressure for each
corner. Peyote happens to be 50/50 front to rear and diagonally, with me
standing in the seat. How Bill Ames knew back in 1959 I would weigh 245 is
beyond me.
I haven't driven many Triumph race cars that belong to other people, but I did
drive Tony Drews, and I was struck by the fact that it handled almost exactly
like Peyote. I also clearly remember the evil handling of my cheater TR3--it's
why I started studying handling so intently. I also discovered you could take
a car that intrinsically handled extremely well--like my Radical DSR--and with
a little work screw it up so it becomes uncompetitive. The difference is
attention to setup (suspension, brake bias, spring rates, etc.) and tire
issues (pressure, alignment, camber).
>>> The only way to get it right is tire temperatures. Honestly, I don't
>> understand why people ask "what tire pressure are you using". You might as
>> well ask "what size pants are you wearing".
>
>
> I think the reason I ask is for a starting point. I use a pyrometer to
> narrow it in, but on these tires the range specified by the manufacturer is
> significantly different than my previous tires. I figured since a lot of us
> drive TR4s they should all be reasonably close as a starting point.
> Likewise if I were in a country that measured their pants in mm or by some
> size instead of waist and length, I would probably ask a guy who was
similar
> in size to myself what size pants he was wearing!
>
> -Mark
> _______________________________________________
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