IT7 hoosier R6 cold/hot tire pressures

[corykrush]

What cold/hot pressures should I be looking for with the Hoosier R6 tire? Size 205/60/13 on an 83 Mazda rx7

[team-gpracing]

Not sure about the first gen, but I like my tires to be at about 28 lbs hot. Cold temps will depend a bit on track temp and layout. 24 is usually what I start with.

[Greg Amy]

Spec Miatas are shooting for 35 hot. I shoot for 38 hot on my Integra. We tried 35 hot on the 'Teg last weekend at NJMP and it SUUUUUUCKED. Hard.

I suggest 28 hot is WAY too low. Hoosier recommends 28 cold as a starting point: www.hoosiertire.com/pdfs/tctR6_A6.pdf‎ (http://www.hoosiertire.com/pdfs/tctR6_A6.pdf)
(http://www.improvedtouring.com/forums/www.hoosiertire.com/pdfs/tctR6_A6.pdf‎)
- GA

[dickita15]

Not sure about the first gen, but I like my tires to be at about 28 lbs hot. Cold temps will depend a bit on track temp and layout. 24 is usually what I start with.

Sterling, aren't you on slicks not DOT's?

[lateapex911]

Yea, 28 hot??? OMG, thats scary on the R6s. That mUST be a slick pressure.

Its hard to suggest proper cold starting pressures as each corner will build differently, depending on car setup and track. And weather.

Also, I think the 205 /60 isn't the best choice of sizes either, but the choice does involve the rear gear so, we'll leave that for another day.

If i were starting fresh, I'd probably start around 32 on a hot summer day, and shoot for 37-38 hot. They are squirmy and slippery at 32 and cold. You will probably end up at 38.5 to 39.5, they build about 7 or so, typ. After adjusting, you might find that you end up with one tire starting at 30.5, two at 31.5 and one at 33, depending on the track, setup, etc, to end up with 38 at all four corners.

I had a crew guy screw up at Summit Point once and we started WAY too high. Wound up at 42 hot. Lap times suffered and it was all I could do to hold 2nd place off late in the race. One more lap and I was toast.

So, 42 hot is TOO MUCH on a first gen.

[team-gpracing]

Sterling, aren't you on slicks not DOT's?

It depends. I run both, I've gotten a couple good deals on R6s for the RX3 and used to run them on my 3rd gen too.

I was looking at my pressures for cantilevers though. Although I don't run much higher with R6s, just 30 hot. they seem fine to me and I feel like Smarty thought those were fine temps as well.:shrug:

Isn't 38-40 lbs way less grippy?

[Greg Amy]

Isn't 38-40 lbs way less grippy?
Actually, no. Per Hoosier, grip increases to around 38-40 hot, but it becomes less "driveable" for someone inexperienced. From there you can use higher pressure to reduce grip/available slip angle to tune balance.

- GA

Edit: see Ho-Ho link in my post #3 above:

"Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.

"One characteristic of the tires is the tendency to “skate” initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the “feel” of the tire however it will also lower the performance and increase the wear rate."

[team-gpracing]

Just read that sheet. They actually recommend a hot pressure of 30-33 for my car (1800-2200 lbs), since my car weighs in at just over 2k. I did begin my original post with the caveat that I was talking about my car, so I'm sorry if I confused the topic starter.

When my car was new (to me) I was running about 34 hot and tuned it down to 30 by my preference.

[corykrush]

Thanks for all the input guys, helps alot!!

Jake,so what rear gear should I theoretically be running with the 205/60/13 tire size on my first gen? I typically run Mid Ohio but plan to venture out to some other tracks this season. I think I'm running a 4.88 but would have to look at my notes again.:shrug:

[joeracerx95]

Thanks for all the input guys, helps alot!!

Jake,so what rear gear should I theoretically be running with the 205/60/13 tire size on my first gen? I typically run Mid Ohio but plan to venture out to some other tracks this season. I think I'm running a 4.88 but would have to look at my notes again.:shrug:

If you are going to run 205/60/13 then you don't want to be any lower than a 4.88. Due to our limited HP, your engine will top out in 5th with that combination at about 7800, 8000 with a draft. I don't know if Ohio will support a 5.12.

I run 225/45/13 w/4.88 on my 1st gen. If I run at Cal Speedway I need to use a 205/60 or I end up at about 8200+. Besides being wider, the 225/45 also drops your car about 1" which is good, but you need to make sure you are not too low for IT rules.

[lateapex911]

If you are going to run 205/60/13 then you don't want to be any lower than a 4.88. Due to our limited HP, your engine will top out in 5th with that combination at about 7800, 8000 with a draft. I don't know if Ohio will support a 5.12.

I run 225/45/13 w/4.88 on my 1st gen. If I run at Cal Speedway I need to use a 205/60 or I end up at about 8200+. Besides being wider, the 225/45 also drops your car about 1" which is good, but you need to make sure you are not too low for IT rules.

What he said ^,
with the caveat that it somewhat depends on your power. If you can't pull the gear to hit top speed, then a higher gear might be needed. But, I ran a 4.88 nearly everywhere, including at Road Atlanta, on the 45 series. (I never had super power either though)