hoosier R6 pressures

[CPLUCKER]

I raced for years on the old hoosiers with a recommended hot pressure of 42 psi for my car, last year I noticed that hoosier recomended a much lower pressure of 33 psi for my weight. when did this change ? I alway like it when you find out you have a problem that is easy to fix, but I feel bit stupid runing the wrong pressure.

Thanks

[mossaidis]

So much varies from car to car, obviously weight, but also suspension geo, static/dynamic chamber, spring rates, shocks, fwd/rwd, driver, temp, etc. i found that at 38-41 psi my car which weighs 2290 fwd runs faster than the recommended psi (from what I remember).

[Flyinglizard]

Start high and work down until you start getting on the sidewwall too much. Than put back in 2#. Per Moss on all points.
As you get closer for target( hot, as raced) pressures you can start to work the camber, pressures, spring rates, as they all work together for best speed.
Optimal lateral grip, front tire pressure should be near 36# but may vary 5# if the setup is way off or set up for good roll/zero scrub. MM

[CPLUCKER]

understand the process for setting them , but whan did Hoosier change the reccomended hot pressure? was it when the R6 came out ? or was it more recently ?

I had a similar situation where I found my front shocks had zero rebound I was all excited thinking I would go a bunch faster when I replaced them ! .. well I fixed the shocks and ended up going just a little bit faster, heck I could hardly tell the difference...

SO I am thinking I have been running with 10 psi too much air pressure for ? how long??? it works o.k. because i have had some pretty good finishes, but I am wondering how much it will help .. if it is like the shocks I will not notice the difference and go the same speed? who knows ?

thanks for the advice.

[JeffYoung]

That's too high. I suspect you are sliding the nose some with pressures like that.

Last time I talked to the App Race Tire guys (and your car is a fairly close analog of mine power and weight wise) they said target 34-36 hot.

If I get into the upper 30s or low 40s, I start to lose significant grip, particularly at the front.

Good luck with it, hope to see you at VIR in March.

[924Guy]

What Demetrius said... usually the lower pressure will feel more confidence-inspiring to a driver, but a slightly higher pressure will provide better lap times... with the 924, the car seems to be right on the money if we can get it to 39.5psi hot...

[Andy Bettencourt]

I like me some 36 hot.

Do a test day. Run a session at your pressures, then a few minutes before it ends, come in and have a friend or crew bleed off all 4 corners to your target to test. Maybe 38 at first, 36 the next time, whatever you think is a good progression for you.

Then you will see how pretty much all 4 corners will be different when cold, record those starting pressures (I start as low as 28 on some corners on some tracks) and start from there every time.

I am willing to sacrifice some speed over the first 1-2 laps for a fast and consistent racecar for the entire remainder of the race.

[Ron Earp]

I generally aim for 35-37 psi with a 2800+ lb race weight on the Mustang. The Hoosier site recommends a target which is roughly the same as where we run them.

http://www.caymaninterseries.org/sites/default/files/Cayman-Interseries-Partner-Bulletin-2011-01.pdf

We never aimed to get the 260Z tires to anything higher than about 38 psi, even in the "old days". I don't remember any recommendations that were above these values.

Searching the web I did run across this though:

http://www.midatlanticmotorsport.com/hoosier_tire_tips.htm

And it has some very high recommendations, but, it isn't specified for what sort of Hoosier tire the recommendations cover.

[JeffYoung]

I like me some 36 hot.

Do a test day. Run a session at your pressures, then a few minutes before it ends, come in and have a friend or crew bleed off all 4 corners to your target to test. Maybe 38 at first, 36 the next time, whatever you think is a good progression for you.

Then you will see how pretty much all 4 corners will be different when cold, record those starting pressures (I start as low as 28 on some corners on some tracks) and start from there every time.

I am willing to sacrifice some speed over the first 1-2 laps for a fast and consistent racecar for the entire remainder of the race.

Or lower. CMP will really work the tire, and Roebling too. Starting mid 20s to get mid 30s hot is not unusual.

[CPLUCKER]

Ron

That older sheet you refrence was the one I have kept in my briefcase for years.I bet that is for the R3SO4's we used to run. I have had my method down for years where I could get them dialed right to 43 psi HOT.... just forgot to read the new litrerature from hoosier

Thanks guys, I am looking forward to new grip this year. I have abunch of new development on the car for this year,

1) new shocks ( custom valved upside down bilstein's)
2) rod ends on the sway bar ( finally getting rid of the old bushings )
3) all sphericals on the front
4) new in cell pump ( so I don't have to carry around 7 gallons of ballast fuel to prevent starving )

plucker
ITS 280z

[erlrich]

That older sheet you refrence was the one I have kept in my briefcase for years.I bet that is for the R3SO4's we used to run. I have had my method down for years where I could get them dialed right to 43 psi HOT.... just forgot to read the new litrerature from hoosier


You're correct sir; this is what they have on Hoosier's website now (which I'm guessing you've already seen):



Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Along with this chart:



VEHICLE SIZE RECOMMENDED HOT PRESSURE COLD PRESSURE
1800-2200 LBS. ..........................30-33+ ..............22-27
2200-2600 LBS. ..........................31-34+ ..............23-28
2600-3000 LBS. ..........................33-37+ ..............23-28
OVER 3000 LBS. .........................34-39+ ..............23-29

[Spinnetti]

Or lower. CMP will really work the tire, and Roebling too. Starting mid 20s to get mid 30s hot is not unusual.

+1 - Mines light at #2030 and RWD, but I start around 25-28psi cold