Hoosier radial tire pressures

D

Don Walsh

Well-known member
I spoke with Tim Gilvin at Hoosier this morning after suffering my 3rd tire failure with the Hoosier radials. I had been told to run the same tire pressures as I had with the bias tires. I was running 21F/20R cold and saw 27-28 F/R hot. The LR failed at the Glen last year with about 12 laps total. The RF failed at Pocono on a yellow flag lap while on the back straight with about 24 laps total on it. This past wekend at VIR the LR failed with about 10 laps on it.
In speaking with Tim, he says the failures were caused by low tire pressure. According to Tim, I should have been running 4 more pounds of pressure, contrary to what I was originally told. Has anyone else had similar problems and what pressures are being run? I'm not looking to diss Hoosier, but I would like to hear if anyone else has any ideas or input. My tires were 245/580-15 R80 compound.
 
Hi Don,

Just my .02, but if I'd had three tires failures, I'd be looking for other tire options. 4psi is the difference between failure and fast?

That said, we'll make sure we have someone from the 71 Crowd on the pit wall with a pyrometer to take your tire temps at Summit next weekend. You coming for the test day on Friday?

-Kyle
 
Tim said he would be at Summit and work with me . I will be coming during the day on Friday. May do the afternoon test.
 
Also not trying to dis Hoosier, but Charlie Campbells car lost 2 or 3 of the radials last year also. I'm sure they(Hoosier) will figure it out eventually. Though I will wait till the failures stop before I try them. Hoosier makes good tires, I just like Goodyears more.
Chris
 
Don-

What's failing? Is it in the sidewall? In the tread?

I like 28 hot (start accordingly) on a car that weighs 2200 lbs. Not sure your weight and if you'd need more. I was initially advised 30 hot, but liked 28 better. Can't remember for sure what I ran Weber's car at for pressures on bias tires--maybe 24 hot?

Have not had a failure in 10 races going back to Runoffs '10 and that includes many sets. I'm aggressive on curbs and rumbles. Not sure what may be causing these for you. Maybe something in setup? How are your temps spread? Gauge reading correctly? (I know, dumb question but I've heard of people chasing stuff and have it be their gauge 3-4 lbs off).

I notice you say its the 245. Was Charlie running 245s as well? Personally, I don't like how they fit on a 7" wheel. I realize Hoosier says its okay, but I don't see a benefit if the tire is pinched down that much. I feel like I'm exposing the sidewall to too much abuse.
 
RonInSD":2p0jzf3e said:
EPrill":2p0jzf3e said:
I'm aggressive on curbs and rumbles and grass.
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I corrected this for you Eric.
Click to expand...

HeHe. Awesome.

Back on topic - I would like to know the nature of the failures. I used way too much air at first, but the tires still lasted forever and just ran out of stick earlier.

Way too much air was 30 hot.
 
3 different Hoosier representatives on 3 separate occasions told me that the new radials would not require high pressures like real radial race tires and to run the same pressures I ran on the bias tires before. I ended up liking them a little higher at 28-29 hot.

I am running the 215-15 on a 6" rim. Hoosier was worried about the bead angle when pinching a tire designed for 7" onto 6" rim but the beads look fine with no cutting or slipping. I would be curious if you are running a full 7" rim and what brand/bead seat?
 
I am running 7" rims. The failures have been the entire tread section separating from the sidewalls. I have checked tire pressures with as few as 4 laps and it was 27#s on all four. The car weghs about 2550#s with my fat butt in the seat.
 
Don Walsh":1nt3xb57 said:
The failures have been the entire tread section separating from the sidewalls.
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Wow I've never even heard of that.

Not trying to point any fingers here - just looking for information - do you always use the same installer? I know these things are a PITA to get on the rim.

Always the same rims?

Wow, just wow.
 
Don Walsh":3306w9je said:
I am running 7" rims. The failures have been the entire tread section separating from the sidewalls. I have checked tire pressures with as few as 4 laps and it was 27#s on all four. The car weghs about 2550#s with my fat butt in the seat.
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I'm no tire engineer, but I wonder if having the edges where the sidewall meets the tread so exposed pinched on to the 7" rims is torturing them, causing a failure.

I would consider trying the 215
 
I wouldn't rule out the width discussion but the examples of this condition are relatively common at places like Daytona if the tire is started at too low a pressure. We have seen this problem on Dunlop, Pirelli, Hoosier and Continental tires. The desired "feel" when the tire is hot drives the guy in the seat. The desire to not have a tire come apart drives the guy on the pit box. Following the recommended cold starting pressures usually takes care of the problem.
 
Don, I have never had a failure in 2 years running this tire( including prototypes) on different 7" wheels--goodness knows I have tried to ruin them with my 2650# Bimmer. Have run starting pressures from 19 to 22 with sometimes as much as 9# buildup. Give Tim a chance at Summit to help you figure out what is happening. Hoosier's techs are the best.
 
^^^ I can mirror Sam's comment pretty much identically. I've been running these for two years, including prototype sets, and have never had any kind of a failure. All mounted on 15x7" Enkei RPF1's, about an equal mix of 245's & 215's. On my 2300lbs FWD car, I like 32f & 28r (hot). To get that, I'm usually starting around 21-23 all the way around. If Tim is going to be at Summit and is willing to do some data taking and working with you, he should be able to get you setup pretty well.
 
I don't have any relevent experience because of wheel/tire size and car weight, but I have not had any failures of the radials for my car and after a decent amount of testing I use exactly the same starting pressures as I did with the bias ply tires. You are woking with the right guy, and Tim should be able to get you sraight if it is a set-up issue. With three tires gone on your car and none on anyone else's it must be something to do with your car.
 
Ron, you missed my post. Charlie Campbell had several failures also. And Charlie uses the Enkei RPF1 rim on a Miata. I believe all have been sidewall failures. Maybe they had a bad run of them. We will never know. I ran a set for a qualifier at Pocono last year and was impressed how supple they were across the berms. They felt faster, but I was 4 seconds a lap slower. I did not change from the bias ply setup, but Pocono is essentially 2 drag strips connected by a short autocross course. I had hoped for higher top speeds but didn't get there in the test. I'll try them again on my GT3 Miata this year. And this time I'll give them a fair test.
Chris
 
Best advice is to work with Tim at Summit. I suspect there's something to be done in setup to cure the issues on the loaded tire. He'll get you squared away.
 
Don -

One word..... Goodyear :D (not that I'm biased - no pun intended!)

Joking aside... if you want some input from a tire engineer, shoot me an email/PM.

Jason
 
Sorry Chris - I did see your post but didn't catch the sidewall failure part of it and thought that you were talking about the issue that Charlie had with running too soft a compound and cording a tire at the runoffs. I knew about that one.
 
Sam Moore":36p7yrww said:
Don, I have never had a failure in 2 years running this tire( including prototypes) on different 7" wheels--goodness knows I have tried to ruin them with my 2650# Bimmer. Have run starting pressures from 19 to 22 with sometimes as much as 9# buildup. Give Tim a chance at Summit to help you figure out what is happening. Hoosier's techs are the best.
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Sam, i thought the BMWs had to weight a min of 3000#,no wonder you and Kevin came in 1st and 2nd. Congrats to both of you. Is the lower weight a misprint :)
larry
 
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