Tire Pressures in HPDE 1 / 2?

[markseven]

Hey guys,

 

I know some drivers bleed off pressure right after a session to even-out pressures when on track. Is this something I should be addressing while in RG 1 or 2?

 

TIA,

Mark

[getfast]

Hi Mark-

 

IMHO, once it's gotten a tech sticker I wouldn't touch a thing on the car in HPDE1... other than:

 

-add gas

-check/fill fluids

-check lug nut torque

-clean windshield

(-maybe check brake pads after day 1)

 

Depending upon the car and the tires, it's usually a good idea to put more air in than you'd use on the street (3-5# more, maybe 35-40 cold) in HPDE1. Look at the tires periodically during the weekend to make sure they're not wearing too unevenly (i.e. outsides of fronts wearing more quickly than insides due to soft suspension and/or not enough negative camber and/or understeer and/or overdriving.) If the tires are rolling over too far onto the sidewall, add a few pounds more air... but otherwise leave 'em alone.

 

HPDE2 is another story, because tire pressures can become a valuable tuning tool once you have found the line and are more concerned with getting fast and turning repetitive laps than just figuring out which way all the corners go and how the car feels at speed. But don't start fooling with tire pressures until you can recognize WHAT you're trying to improve and WHERE you will see that benefit, because you will be making the learning curve that much more complicated as a result. And the last thing you want is a car that handles differently every session, since many related deficiencies can be fixed with adjustments to driving style first and foremost.

 

The reason you see more experienced drivers bleeding pressures is because they have a certain cold pressure starting point in mind based on prior testing, but tires will gain pressure as they heat up (and usually the left side will get hotter than the right due to the clockwise configuration of most road courses, i.e. more right turns.) Alignment plays a huge role in this as well... the more optimized your alignment (and suspension, and handling for that matter) are, the less tire pressure adjustment you'll need to make during an event. The pressure differences also become a lot more noticeable on R-compound tires instead of street tires.

 

Too much information?

 

Hope it helps,

 

Jon

[markseven]

Hi Jon,

 

Thanks for the insight; your in-depth, salient response is exactly what I was looking for. Much appreciated.

 

Mark

[kbrew8991]

set it up towards understeer if you can, its safer and will help you master the stuff you need to in DE1

 

(what Jon said is very good advice as well)