Radial slick pressure

GallopinGhost · 09-19-2019, 07:46 AM

Can someone give me a good starting point on tire pressure as I just got some new hoosier lightweight radials. E-body stocker, almost 3500 lbs, was 1.58 60 ft with bias ply. thanks

Pete Lanciers · 09-19-2019, 07:57 AM

Brian,

I have found in my 3100lb E/SA Duster that 22lbs gives me consistent aggressive 60ft times.... 486 rear, 10 inch rims, Tri-City Competition Launchers with Rancho rears...

Pete

dartman · 09-19-2019, 08:09 AM

20lbs is a good starting point.

1320racer · 09-19-2019, 08:47 AM

Having run radial slicks of various sizes for 20 years, over 5000 passes, on two different doors varying greatly in weight and power, one that has 60 footed a best of 1.28 and the other 1.17, both launched off the footbrake, I can tell you that 18-22psi is the sweet spot regardless of power, weight and tire size. Some run as much as 24 psi, but they are typically lowered powered cars and the result is they are also not using the entire thread face.

That said, the extension and rebound of your rear shocks will need to be optimized for the radial tire.

Tom Goldman · 09-19-2019, 08:49 AM

At that weight 20-23# is a good starting point.
you really need to run a test session , increasing the pressure each pass to see where the tipping point is for spin and then back down to find the highest pressure that yields the quickest 60'.
Shock settings will have a big effect on your final pressure also .
Bias tires are so forgiving you can miss by a half pound and get away with it , Radials ,they love to teach you their limits, usually at the worst time !.
Before you start ,invest in a good quality gauge that does not greatly exceed the pressure range you expect to run and use it only for the slicks.
A zero to 40 # gauge with 1/4 pound increments is usually the ticket ,especially since most dial type gauges are most accurate at mid scale.

Lenny5160 · 09-19-2019, 10:32 AM

My Nova weighs 3575 and goes 1.41 off the transbrake. On at 10" wide rim, I've tried everything from 16 - 26 with the Hoosier 9" radial and the car always works the same. I use air pressure to try to get even wear across the tire.

I've pretty much settled on 17 psi but I still wear the centers out first, and that's even with the wide rim. I usually check the tires before the first and second passes of the day, and then I don't bother. I don't use the line-lock on the burnout; very short. The car just works and I'll get 150-200 passes from a set but I don't use the lightweight version.

GallopinGhost · 09-19-2019, 10:34 AM

I'm planning on running the divisional at VMP, and it looks like I'll have 2 more TnTs before then. I'll go to richmond this friday evening and could get 4 passes in at best. So based on what you guys are telling me, I think I'll do this. Start out at 20 and do 2 passes. Then 22 and 24. decent plan ?

Lenny5160 · 09-19-2019, 10:44 AM

Quote:

Originally Posted by GallopinGhost

I'm planning on running the divisional at VMP, and it looks like I'll have 2 more TnTs before then. I'll go to richmond this friday evening and could get 4 passes in at best. So based on what you guys are telling me, I think I'll do this. Start out at 20 and do 2 passes. Then 22 and 24. decent plan ?

20 is a fine starting point, but you aren't going to see a difference in performance making small psi changes.

How your front suspension works is far, far more important than +/- 2 psi in the radial slicks. If that part is good, the air pressure is only going to impact how the tire wears. If the car doesn't transfer well, you're going to go up in smoke and psi adjustments won't help.

It did take me a lot of work to get to that point, but I'd never use a bias tire on my car again.

Dan Fahey · 09-19-2019, 11:25 AM

With a prepped track for S/SS races have run 26 lbs NP.
In fact 30 lbs by mistake at same race. Hooked fine.

Bracket racing that are less maintained.
Use 22-23 lbs in a 4200lb ImpalaSS

Myron Piatek · 09-19-2019, 12:04 PM

Rim width also has an in influence on pressure. The wider the rim, the more pressure you can run...which is better because it will extend the life of the sidewalls. I have the Hoosier lightweights on 10" rims at 21 lbs on my 3,540+ lb 360 Dart, footbraking and SS springs. Especially with new tire, you can usually see if the tire is making full contact all the way across.

But even if it hooks with more pressure, and theoretically goes a bit faster, you want to keep as much rubber contacting the ground as possible for a little extra "insurance" (consistency).

You should pick up a little ET and RT with radials over bias play.

You may need a touch more pressure once you get the car to leave harder (lower 60').

09-19-2019, 07:46 AM	#1
GallopinGhost Member Join Date: Jun 2010 Location: VA Posts: 228 Likes: 23 Liked 21 Times in 13 Posts	Radial slick pressure Can someone give me a good starting point on tire pressure as I just got some new hoosier lightweight radials. E-body stocker, almost 3500 lbs, was 1.58 60 ft with bias ply. thanks __________________ Brian Carpenter Stock 1358

09-19-2019, 07:57 AM	#2
Pete Lanciers Member Join Date: Mar 2009 Location: San Diego Posts: 368 Likes: 807 Liked 562 Times in 145 Posts	Re: Radial slick pressure Brian, I have found in my 3100lb E/SA Duster that 22lbs gives me consistent aggressive 60ft times.... 486 rear, 10 inch rims, Tri-City Competition Launchers with Rancho rears... Pete __________________ Pete Lanciers PAL Automotive Racing Stock 7801 Last edited by Pete Lanciers; 09-21-2019 at 12:48 AM.

09-19-2019, 08:09 AM	#3
dartman Member Join Date: Oct 2005 Location: N.S. CANADA Posts: 498 Likes: 155 Liked 68 Times in 41 Posts	Re: Radial slick pressure 20lbs is a good starting point. __________________ 1231 FS/D Drag Pak 1231 E/SA 71 Demon Kelly MacKay

09-19-2019, 08:47 AM	#4
1320racer VIP Member Join Date: Nov 2007 Location: New Jersey Posts: 1,778 Likes: 70 Liked 400 Times in 191 Posts	Re: Radial slick pressure Having run radial slicks of various sizes for 20 years, over 5000 passes, on two different doors varying greatly in weight and power, one that has 60 footed a best of 1.28 and the other 1.17, both launched off the footbrake, I can tell you that 18-22psi is the sweet spot regardless of power, weight and tire size. Some run as much as 24 psi, but they are typically lowered powered cars and the result is they are also not using the entire thread face. That said, the extension and rebound of your rear shocks will need to be optimized for the radial tire. Last edited by 1320racer; 09-19-2019 at 08:53 AM.

09-19-2019, 08:49 AM	#5
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,436 Likes: 776 Liked 700 Times in 204 Posts	Re: Radial slick pressure At that weight 20-23# is a good starting point. you really need to run a test session , increasing the pressure each pass to see where the tipping point is for spin and then back down to find the highest pressure that yields the quickest 60'. Shock settings will have a big effect on your final pressure also . Bias tires are so forgiving you can miss by a half pound and get away with it , Radials ,they love to teach you their limits, usually at the worst time !. Before you start ,invest in a good quality gauge that does not greatly exceed the pressure range you expect to run and use it only for the slicks. A zero to 40 # gauge with 1/4 pound increments is usually the ticket ,especially since most dial type gauges are most accurate at mid scale. __________________ Tom Goldman 1500 SG , 1506 STK

09-19-2019, 10:32 AM	#6
Lenny5160 Senior Member Join Date: Nov 2015 Location: Inver Grove Heights, MN Posts: 898 Likes: 604 Liked 432 Times in 225 Posts	Re: Radial slick pressure My Nova weighs 3575 and goes 1.41 off the transbrake. On at 10" wide rim, I've tried everything from 16 - 26 with the Hoosier 9" radial and the car always works the same. I use air pressure to try to get even wear across the tire. I've pretty much settled on 17 psi but I still wear the centers out first, and that's even with the wide rim. I usually check the tires before the first and second passes of the day, and then I don't bother. I don't use the line-lock on the burnout; very short. The car just works and I'll get 150-200 passes from a set but I don't use the lightweight version. __________________ S/ST 51 S/C 53

09-19-2019, 10:34 AM	#7
GallopinGhost Member Join Date: Jun 2010 Location: VA Posts: 228 Likes: 23 Liked 21 Times in 13 Posts	Re: Radial slick pressure I'm planning on running the divisional at VMP, and it looks like I'll have 2 more TnTs before then. I'll go to richmond this friday evening and could get 4 passes in at best. So based on what you guys are telling me, I think I'll do this. Start out at 20 and do 2 passes. Then 22 and 24. decent plan ? __________________ Brian Carpenter Stock 1358

09-19-2019, 11:25 AM	#9
Dan Fahey VIP Member Join Date: Oct 2008 Posts: 2,114 Likes: 1,078 Liked 180 Times in 110 Posts	Re: Radial slick pressure With a prepped track for S/SS races have run 26 lbs NP. In fact 30 lbs by mistake at same race. Hooked fine. Bracket racing that are less maintained. Use 22-23 lbs in a 4200lb ImpalaSS

09-19-2019, 12:04 PM	#10
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,538 Likes: 34 Liked 132 Times in 48 Posts	Re: Radial slick pressure Rim width also has an in influence on pressure. The wider the rim, the more pressure you can run...which is better because it will extend the life of the sidewalls. I have the Hoosier lightweights on 10" rims at 21 lbs on my 3,540+ lb 360 Dart, footbraking and SS springs. Especially with new tire, you can usually see if the tire is making full contact all the way across. But even if it hooks with more pressure, and theoretically goes a bit faster, you want to keep as much rubber contacting the ground as possible for a little extra "insurance" (consistency). You should pick up a little ET and RT with radials over bias play. You may need a touch more pressure once you get the car to leave harder (lower 60'). __________________ LOCOMOTION Racing Last edited by Myron Piatek; 09-19-2019 at 12:06 PM.