333pg333

It is a bit of a concern for me. I'm sure there are other things to throw into the mix such as the car, weight and distribution, track..etc...but I was intending running r80 305/320 for short sprint duration events. Car is highly modified 951 weighing in at approx 2600lb. From what I can see of the other competitors who run the expensive Michelins, they tend to take longer to heat up and we see this as a major advantage of the Hoosier.

mwest

Seems like this thread has been around awhile but I just came across it in my search re:Hoosier Radial Failures
In addition to my Boxster I have a V8 Miata track car. I do only HPDE.
I'm in the instructor run group. I run with PCA, NASA, BMW etc.
Last year I switched from Toyo 888's and RA1's to Hoosier Bias Ply Cantilevered Slicks(take offs). I loved these, but most tire shops don't want to or can't mount these. A few weeks ago I switched to a radial version of Hoosier slick, similar size to the bias ply.

After a few laps at NJMP Lightning track my left rear tire blew out in the bulb. At the time we were going 3 wide in the bulb, me in the center and a Ferrari right behind me on my bumper. Suddenly I felt something & I was spinning out of control. It was amazing luck I did not hit anyone and the quick reaction of the Ferrari driver who went up and around me and onto the grass and just missed me. The hole in the sidewall was 5" long and about an inch wide. My car weighs 2452 with me in it and has 306hp at the wheels and a 4" wing on the rear.
I ran with 25psi. 2 weeks later I was at WGI after a few laps coming out of the bus stop I felt something odd, like maybe a flat on my left rear. I started to limp off and made it to turn 6 where I went offline and pulled onto the grass. The left rear tire had completely separated into 2 separate pieces. The inside sidewall completely separated from the tread. I called Hoosier & sent pics of both failures to Jeff Speer. He said both were symptoms of not enough PSI. He said with my power and wing I should be 30-32psi. Was at WGI again a few days ago. Ran the morning with the bias Hoosiers with no problems except that I wore 2 of them down to the cords. Switched to the radials pumped up to 32psi. After a few laps I felt that all to familiar sensation and was able to limp off the track. My left rear had a 1" hole in the outside sidewall. Mounted up the last of my radials.. After another few laps here we go again. This time a 1" hole on my right front inside sidewall.
I now have only 3 useable radials & 2 bias ply. I decide to run the radials on the front and bias in the rear. Logic was better tires in rear and radials may give better turn in --in front.Handling & grip with bias & radial felt OK. Managed only a few laps when left front radial failed. Made it off the track with another 1" hole in my inside sidewall. There were absolutely no signs of anything rubbing anywhere. The bias never gave me any problems. There was a big event happening the following day at WGI. I saw various major tents being set up, one being Hoosier. I headed over there. They were from Hoosier Corp. I spoke with them about my problems and showed the tires but they had no answers. They said there road racing expert was showing up tomorrow. It was Jeff whom I'd been speaking with, but I could not stick around till Fri. Looks like I'll be sticking with the bias ply or maybe looking for another brand of slick. Anyone have any other suggestions.

mikew968

Pirelli DH slicks. I loved the feel of the Hoosier but could not get any life from it. The Pirelli's were take off and still were fast and they seem to last pretty well!

coryf

We had issues with Hoosiers a few years ago but have had good results the past 2 years. We use the s100 which is the new construction and can handle more negative camber.

What sizes tire are you using?
Is 32 your starting pressure or hot?
Alignment settings?
You mentioned buying takeoffs. Are these used tires?

Martin S.

I am going to wait for the R7 in 2015...too many R6 horror stories floating around. Remember the Kumho 710, out west we had plenty of failures, one such failure on my car, Turn 2 at California Speedway, 120+ mph, in a sweeper corner and the right rear let loose...failed. Three (3) snap spins later, came to a stop, didn't hit a wall, or contact any other cars....that was the end of the Kumho 710 experience for me....they were a great tire, for a time...they are still for sale at Tire Rack, but nobody seems to run them.

I have heard that the original tire 710 was re-engineered, maybe it is a good tire, but for me, I'll wait for the 2015 Hoosier R7 to become available in a wide range of 18" sizes (Now limited), or maybe graduate over to Yokohama slicks.

jakermc

The reported problems with Hoosiers have largely been with the slicks, not the R compound. I won't run the slick anymore but has no second thoughts of throwing on an r6 or a6.

333pg333

An alarming rate of failures for mwest though!!!!! I haven't run the Hoosier or any slick for a while as we have a large event down here that the Yokohama AO50 is the control tyre. So we've been running that for now. It's about the fastest R spec rubber out there in the market place but only ships to very few places on the planet. We're running as fast or faster than the 991 Cups are on their Michelins. However I want to run slicks next year in our local club events but can't see myself going back to Hoosiers anytime soon. We have way too much downforce to run a brand that has had so many reported failures. Need to find a suitably sized slick that heats up faster than the typical Michelin shod Cup car.

Tom W

I've been running the Hoosier radial slicks in 23.5x11x16 (f) and 25.5x13x16 (r) using the R75 or R75A compound on my car (2400 lb with me, 300 rwhp) for two years (over 12 sets of tires) and have not had a single problem. I run mine at ~28 psi hot. I have always started with new tires and get ~10 30-minute sessions/races out of a set before they seem to lose grip (despite still having "tread").

Have you ever measured tire temperatures to see how hot you are getting them? (I see 175-200 degrees.) I know you are seeing sidewall issues and not tire surface but it's nice to know what's going on. On my car 25 psi hot would be too low (I go out at ~20 psi to get them to 28). What pressure do you go out at and how do you get them warm?

philstireservice

Tire pressure is critical on all cars that go on the track. Slicks are even more or technical nightmare in regards to tire pressure cold (starting) as well as hot (on track). Everyone should use a tire pyrometer to set pressures, no excuses. You'll spend thousands on a car and tires but not $200 on a tire pyrometer.

One very common mistake is most don't let the tires heat up enough before they push the car. You can very easily crack a R6 or a slick with not enough cold pressure and big wing on the back of your car before they warm up. Not too mention "grain" the tire to where there is no grip left in the tire at all. a race tire has to brought up to temperature gradually before you pounce on it....a half a lap is not enough. Sometimes it take two.

333pg333

So are there no slicks that come up to temp in under 2 laps? What are those soft compounds for then?

mark kibort

I had a R100 side wall crack, but that was probably because it was left flat on the car for a day or so before I noticed it in the garage. or maybe it happened at the track.. but looks like it was caused by low air.
I just had a A6 with 2 heat cycles blow up , side wall failure at the runoffs. tire too destroyed to see where the failure started from. that's my first that wasn't my fault . (rubbing, etc)
pressures 30hot with R100, 34hot with A6

philstireservice

The information I stated is general. Geography does come into play. Car set up, ability to warm up tires and not blow them up or go off track is important also, as well as other factors.

Yes softer compounds come up to temp quicker and lighter cars can take advantage of a softer tire more so than a heavier car.

333pg333

Thanks, that's what I figured. Our car is pretty light (2500lbs wet no driver) and has a ton of downforce (literally) but we need the tyres to come up to heat a bit faster than what it appears the Michelin shod Cups take. Shall keep looking around to see what's out there.

mark kibort

ended one qual session after a lap

Cupracer

I have been running both the slicks and the DOT Hoosiers for years with virtually no tire issues (other than cording them)