Anyone here have experience running with Hoosier R7?, tire pressure questions. Options

[jmz]

I'm trying to get the tire pressures right on the R7s on my 914/6/gt. Running 275x35x15 and 245x40x15. I initially started at 22 shooting for 27 hot but I think they like to be run a bit lower than that.

I'm nowhere near what Hoosier recommends though.

Any thoughts?

[brant]

your still too high of a pressure at 22
I think we are 20 or 21 cold

what is your vehicle weight?
also those tires are really large to heat up at on a light weight car. The tire is designed to cover such a wide range of modern performance cars. it has to work well on a 3000lb corvette and is designed more for that than it is on a 2000lb 914

which motor? (hp? are you)

we had to work with a hoosier tire tester/pro and the factory engineer to get 7's to work. Ultimately we found at our weight that even with a 225 the car was too light to heat up the tires at our low horse power.

we switched to A7's because they heat up better with a light car.

have you taken any tire temps?

[jmz]

-Brant,

The car is a bit over 2100 lbs without the driver. It has a potent 2.5 twin plug that i run in group 1 (FIA) in my local vintage race club so I'm running with the big American V8s and the 911 RSRs.

I've got two weekends on them and I've been bringing tire pressures down so far... I have not taken temps yet but that will be next I suppose but not until February. Jeff at Hoosier recommended starting no lower than 20 to after speaking with him and thought 25 hot might be a good number. I had gotten up to about 27-28 after starting at 22 the first weekend. This past weekend it was near freezing so I started at 24 but after the first session I knew it was too high. I bled them and targeted a hot temp of around 25 after the third time out. The car responded pretty well for that session just a bit loose on the high speeed carousels.

I was concerned since I was running so much lower than the recommended numbers on the datasheet that something was really off but I think you are right its just a different beast than a 3000lb American car.

I may try something else next time around if I don't get fully satisfied with the Hoosiers. ...maybe R888R as I've heard some pretty good things about them.

your still too high of a pressure at 22
I think we are 20 or 21 cold

what is your vehicle weight?
also those tires are really large to heat up at on a light weight car. The tire is designed to cover such a wide range of modern performance cars. it has to work well on a 3000lb corvette and is designed more for that than it is on a 2000lb 914

which motor? (hp? are you)

we had to work with a hoosier tire tester/pro and the factory engineer to get 7's to work. Ultimately we found at our weight that even with a 225 the car was too light to heat up the tires at our low horse power.

we switched to A7's because they heat up better with a light car.

have you taken any tire temps?