Radial Slick air pressure confusion

[SUPERSTOCKRACER]

Im trying to get a handle on Hoosier 30 x 10.5 x 15 Radial slicks.
I have heard that you need to run 22 lbs at the track for them to work also having a fairly heavy car you would think you would need more air pressure. WRONG!!!!
1st pass was spinning like I was on the street. Couldn't hook whatsoever.
So there was a guy there who was running them on his Camaro and he weas sdame weight as mine and he said he runs 10 lbs.
anyone have any real world experience with radial slicks not drag radials.

 

[68 HEMI GTS]

i had a pair of BFG radials on my high 11sec belvedere, i think i use to air them down around 12 or so before they would grab at the track. shoot, the set i run on my RR on the street i run at just 20, and i know from playing with it the less air the better it grabs. i wouldn't hesitate to air them right down at the track. seems backwards from what i've read also but they kind of act like slicks to me.

 

[alleyoopmgv]

SSR, I run Hoosier 30 x 9 x 15 Radial slicks. I do also have a pair of Hoosier 30 x 10.5 x 15 Radial slicks for backups. On my car I run about 17-18 lbs. Thats what works for me, just saying.

 

[Photon440]

How wide are the rims?

 

[SUPERSTOCKRACER]

How wide are the rims?

15 x 10" RIMS weld alumastars.

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SSR, I run Hoosier 30 x 9 x 15 Radial slicks. I do also have a pair of Hoosier 30 x 10.5 x 15 Radial slicks for backups. On my car I run about 17-18 lbs. Thats what works for me, just saying.

tried 22lbs and it wasn't pretty,i was told to air them up for a heavy car. there was a guy in the lanes who went down to 10lbs.on his radials.go figure
I put on my 31 x 10.5w so I could get a few laps since it was getting late. I should have given them another try with less air in them.

 

[67 coronet]

test and tune is much more effective then opinions.any reason you are trying the radial slicks,if i may ask?

 

[SUPERSTOCKRACER]

test and tune is much more effective then opinions.any reason you are tr
ying the radial slicks,if i may ask?

heard it good for 3 miles an hour and .15 if they hook
always looking to go faster you Know
have you ever use them

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trying to keep up with the big boys. lol

 

[67 coronet]

have not tried them.my current race car is all about consistancey and is very old school.if you are looking to go faster,then by all meens give it a try.you just need to be able to do a ton of testing to make sure they are working for you.22 psi is way too high for any strait line,true slick i have heard of.seems like you would run on the crown of the tire no matter how heavy the car is,giving you a smaller foot print.radials are much more sensative to presure then bias designs since they become more rounded with more presure.1 or 2 psi can have an adverse effect.

 

[actionange1]

Some info from the Stock and Super Stock guys
http://classracer.com/classforum/showthread.php?t=28448&highlight=Hoosier+radial+slicks

 

[Endangered Species]

We always ran around 18lbs.

 

[Furyous]

What I always thought to be true is to run them like a drag radial. My old Mustang I use to race on 2 kits I would run 17lbs in the BFG's..

 

[theman440]

Call the Hoosier tech line and talk to them.

I run 30x9 radials on my 3650lb car and run 'em @ 20psi.

 

[Afxwedge]

We ran 18 too

 

[RacerAL]

i run 30x9 hoosier radials on a 10 inch wheel and i run 18.5 lbs. of air pressure. im wondering if you are just on a track with marginal traction ? i cant run my radials at my home track the track prep just isnt good enough. the radial slicks are not very good on marginal tracks. however when i went to norwalk last fall i ran them, and got my new best et and mph. are you running any weight ballast? i know most stockers run a fair amount of ballast and seem to have alot of luck with the radial slicks. i run 100lbs. of ballast.

 

[theman440]

i run 30x9 hoosier radials on a 10 inch wheel and i run 18.5 lbs. of air pressure. im wondering if you are just on a track with marginal traction ? i cant run my radials at my home track the track prep just isnt good enough. the radial slicks are not very good on marginal tracks. however when i went to norwalk last fall i ran them, and got my new best et and mph. are you running any weight ballast? i know most stockers run a fair amount of ballast and seem to have alot of luck with the radial slicks. i run 100lbs. of ballast.
View attachment 112721

I noticed that you run a 10 inch wheel - do you have stock wheel wells?

 

[SUPERSTOCKRACER]

i run 30x9 hoosier radials on a 10 inch wheel and i run 18.5 lbs. of air pressure. im wondering if you are just on a track with marginal traction ? i cant run my radials at my home track the track prep just isnt good enough. the radial slicks are not very good on marginal tracks. however when i went to norwalk last fall i ran them, and got my new best et and mph. are you running any weight ballast? i know most stockers run a fair amount of ballast and seem to have alot of luck with the radial slicks. i run 100lbs. of ballast.
View attachment 112721

THE TRACK WAS SO GREEN LAST SATURDAY. I never saw it so bad, i thought there was something wrong with the car.
I dont run any ballast at all. i was looking to see if i was going to get a new personal best but instead got my new personal WORST in this car.
I only gave it one shot because we were running out of time due to bad early morning conditions and track didnt start running till 1:30 pm

 

[actionange1]

ops:Maybe you should've talked to these guys. They seem to have had it figured out. Just sayin..

Taken from another tread on For B bodies only:
I agree with budnick the weather affects engine performance more than the chassis... Thats when data comes to play documenting track and weather condition to make the right call. I was at LVD saturday it was cold and damp out testing a car that has it been at a track in two years we check the past data set the car up first pass was the best best ever on the 9.05 1.27 60 It's about documentation!!!!!!ops:

 

[Budnicks]

Track conditions are a big factor too I'm sure... All though I don't run Radial Slicks {I have run drag radials, with relatively good success}... I personally think under inflating them, will hurt just as much as over inflating them, under inflation they will cup & shake/rattle the tires, especially with the power SSR is making, over inflating them your riding on a crown, I would maybe try different air pressures & measure & look at the contact patch after doing you burn out & launch, compare the different air pressure setting sizes of contact patch when leaving, try having a video record you launch too, directed at the tire to see how much spin your actually getting, with each change & setting, that's what we use to do at every track we went to & logged/noted the data in a note book, to refer back to... Also too long or even too short, of a burnout on certain compounds regardless of Radial or Bias Ply Slicks, can hurt your initial launch too, you will need to find what combo you car likes, test & tune on a warm day at a decent prepped track will help too, I'm sure too... I see a overwhelming consensus of around 18-20-22-psi for many guys running the Radial style slicks, on several site I've seen responses at, that 10-psi was probably too low, from all the stuff I've seen & read, I don't know for a fact myself, just others conjecture... I wish I could help more... Good Luck SSR

 

[SUPERSTOCKRACER]

Track conditions are a big factor too I'm sure... All though I don't run Radial Slicks {I have run drag radials, with relatively good success}... I personally think under inflating them, will hurt just as much as over inflating them, under inflation they will cup & shake/rattle the tires, especially with the power SSR is making, over inflating them your riding on a crown, I would maybe try different air pressures & measure & look at the contact patch after doing you burn out & launch, compare the different air pressure setting sizes of contact patch when leaving, try having a video record you launch too, directed at the tire to see how much spin your actually getting, with each change & setting, that's what we use to do at every track we went to & logged/noted the data in a note book, to refer back to... Also too long or even too short, of a burnout on certain compounds regardless of Radial or Bias Ply Slicks, can hurt your initial launch too, you will need to find what combo you car likes, test & tune on a warm day at a decent prepped track will help too, I'm sure too... I see a overwhelming consensus of around 18-20-22-psi for many guys running the Radial style slicks, on several site I've seen responses at, that 10-psi was probably too low, from all the stuff I've seen & read, I don't know for a fact myself, just others conjecture... I wish I could help more... Good Luck SSR

after the 1st pass I came back to the pits and one of the NENDRA members pointed out that only 1/2 the slick even made contact on the track surface. the other 1/2 the nubs were still there and weren't touched at all, that being on each inner and outer side of the slick meaning overinflated even at 3387 lbs.
this car usually can hook in the sand,so I know something was wrong even changing to bias slicks it helped some but still got squirrely.

 

[RacerAL]

yea. stock wheel wells , i did trim the inner wheel opening lip. i had the rear axle cut to fit this wheel/slick combo.