ITS Hoosier PSI?

[paulydee]

Hey Gang,

I had a rough morning at IRP and something came up which I thought warranted a question on this forum. What tire pressure are you Second Gen guys running in your Hoosiers? Since I have been running them I have been starting at 36psi cold. I remember someone telling me since the tires have a stiff side wall and the tread is pretty thin that they need more pressure to begin with.

Is this true? I was talking to the 1st place qualifier and he starts at the high 20's cold. This seems the opposite of what I have been told.

Help me out on this one guys (Chris? Andy?)



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Paul D'Angelo
73 ITS CENDIV
Indy Region
http://www.iridiumracing.com

[C. Ludwig]

Man it must be nice to sleep in your own bed on a Saturday night of a race weekend!

Hoosier told me to look for 38-42 hot on the R3S03s. No idea on the new tire. I usually see about 4-6psi buildup so we start them accordingly.

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Chris Ludwig
08 ITS RX7 CenDiv

[Eagle7]

I'll let you know what I find out next Friday at Grattan T&T. As far as I know, the pressure should be set with a tire pyrometer, setting the center temperature to the average of the inner and outer. I've been planning to shoot for 41/42 hot but don't know how that'll work out.

BTW, what did your rough morning entail? Hope you didn't break anything.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[paulydee]

Nothing got broken, but I managed to destroy four perfectly good Hoosiers (5 heat cycles), by a huge spin coming out of 1. Four flat spots deep into the chords. I spent a considerable amount of time getting replacements (3 I had in storage, 1 I bought off a fellow competetor).

Pauly D

[Eagle7]

Ouch, that hurts. My wife has forbidden me to do that

Learn any more about Hoosier pressures today?

You going to make it to Grattan at the end of the month? Love to meet you.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[paulydee]

The end result of the pressure contraversy was lower pressure to start (29 in am, 28 in afternoon) resulted in a much more stable car. I qualifed second in class and third in group as a result.

As for Gratten, it is up in the air right now but I may be crewing for a guy that will be driving my car. I will let you know.

Pauly D

[joeg]

My experience is that Hoosiers can pump up over 10 PSI (even more on the LF)in a session.

Cheers.

[Doug Ford]

I usually start with them in the 30's depending on weather and try to get them around 40-41 hot. When i come in or stop in the pits get someone to check them and bleed them down to 40 or 41 while they are still hot. After a while check them and see how much they have dropped after they cool down. should give some idea given the temp. outside.

Just an idea that I have tried!!!

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1989 Mazda rx-7 red ITS #12
1995 BMW 325is White
2001 supercrew white (tow vehicle)
Regional Executive Midsouth Region #66

[Eagle7]

Originally posted by Eagle7:
I'll let you know what I find out next Friday at Grattan T&T.

Sorry, rained out.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

[ITSRX7]

Just had a new set at LRP last weekend. I started using my Goodyear numbers (34 cold to get to 40 hot) and went WAY above what was working. Ended up at 48-49 on the critcal corners.

In discussion with one key guy who has tested already, 44 hot was the goal so I adjusted accordingly. Ended up starting with 28-29 cold.

FWIW, the improvments in lap times are not there yet for the RWD guys that the FWD guys are seeing. Frankly, we thought the Goodyears were the best tire last year and they may be at least the equal of the new Hoosier on a 2700lb RWD car...

Take notice to what the AS guys find fast at the Runoffs...

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports
New England Region
www.flatout-motorsports.com

I didnt want to speak out cause I run a 1st gen but ive tried hi and low with the hoosiers and 29 rear and 30 front cold (70 to 80 deg) produced the most stable results.