jrgordonsenior

Great stuff Larry.... Another point worth mentioning is with respect to starting cold pressures is staggering front-to-rear on 911 platforms to accomodate the rear engine load. Front tires do not generate heat at the same rate as rears due to load distribution. Regardless of the track, I always set my fronts 2lbs. higher than the rears to start in the mornings. I bleed after 5 laps or so and usually it's still only the rears that need adjustment and maybe the outside front. You can easily damage tires with too low of pressure, I set mine knowing I'll bleed them after 5 laps.

I also stagger pressures side to side based on track direction when cold. The inside tires will not generate as much temp as the outside tires. So I stagger F to R, and simutaneously side-to-side. It would look something like this on a CW course:

LF= 24 RF= 25

LR= 22 RR= 23

Oh and someone mention no gaining more than 6 lbs from cold. Huh? I'm on N2 and I always gain 10 lbs....

333pg333

I think that is the pressure recommendations right off the Hoosier site for their Radial slicks. I got it off Bob Woodman's site. Seems incredibly high, agreed. 30psi seems a bit low to me though, but you've clearly found the best for you. As far as cold pressure stagger, what if you have e.g. 4 out of 12 rh turns on an anti clockwise track?

jrgordonsenior

I would still stagger for only 4 out of 12 turns. What you're trying to do is help all of your tires to get up to temp ASAP. You should definitely be bleeding them in the hot pit either mid session or at the end of the first session. Oh and don't do the cool-down lap thing if at all possible. Don't run over anyone either, but you want to take those temps with the tires as hot as possible, fresh off the track.

I always ask the powers-that-be in the morning meeting about bleeding tires in the hot pits to make them (and everyone else) aware of your intent.....

va122

I run 30/31 on the Hoosier slicks like JR.

333pg333

Seems really odd the pressures that they're advocating? Has anyone run higher pressures on these and found them to get progressively squirrely?
They also advocate running the new ones up to heat over 5-7 laps and then come in and let cool down to ambient temp just to increase longevity. Do you guys all do this?

kush07

That was my point. The OP stated that the inside temp would be lower than outside. Didn't make sense to me.

J richard

Larry,
This is a great idea, but as usual there are so many different approaches to the same problem that if I were a newbie and hit this thread I would be more confused than ever...

I personally would give specific guidance off of factory recommended pressures (or tire mfgr for type Rs or slicks, but I'd be concerned if a new student shows up on slicks) and then describe the process of adjusting the tire from there, and which process to use give the tools that the student might have; visually by looking at the sidewall, temps with a pyro, chalk, each is different and you don't want to confuse them.

Since this is PCA there's plenty of common experience here to give solid advice on cold/hot pressures for car and tire type...
Then the discussion on how the tire behaves, builds heat and pressure, which could fill an encyclopedia....

Teach em how to fish...