Another tire pressure question

Chevy454 · 07-17-2008, 12:28 PM

Dad put a new set of GoodYear 31x13s on Red Alert a while back...compound is a D-5 I believe? They said as heavy as the car is, it needs the harder compund...anyway, does anyone have any guesses where we need to be pressure-wise? He's been running it at 8-9psi (on a recommendation from someone else), but I think it's too low...looks to me like the tires are cupped in the center and need more air (according to the contact patch). I'll have to say, for a heavy car leaving off the foot brake, it's been dead consistent so far in the short times (1.69-1.71)...

Any help is appreciated!!!!

Bob Verwold · 07-17-2008, 01:36 PM

Thats the same tire I run and I run them at 101/2 lbs, car weighs 3020 but the car hooks good if this helps. Started out at 6 and kept adding air until the car started to fall off then backed off a1/4lb.................

Chevy454 · 07-17-2008, 02:01 PM

Ok...kinda what I was thinking, but it's been a couple cars ago since I've raced anything with stickies regularly. Quick question: with this D-5 compound, are we gonna need to boil these things in the burnout box before each run to get them to hook? Also, is looking at the contact patch from a tire a good indicator or correct pressure, or do I just need to worry about what the timers tell me?

Looks like we've got about 1,000+ pounds on your car, though! Need to get to the scales, but I'm sure an original body/paint/interior '70 LS6 Chevelle with automatic, power windows, and even rear window defrost ain't gonna be a lightweight! She might not be "fat", but she's for sure "big boned"! LOL!!

Mike Pearson · 07-17-2008, 03:06 PM

That sounds a little low for that heavy of a car unless you have them mounted on a narrow wheel. I would start out around 11 lbs and check the contact pattern. The more even the pattern the longer the tires will work good for you. That even seems like a sall tire for that type of car. Usually the big block cars like a taller tire.

07-17-2008, 12:28 PM	#1
Chevy454 Junior Member Join Date: Sep 2002 Location: Alton, Missouri Posts: 84 Likes: 0 Liked 0 Times in 0 Posts	Another tire pressure question Dad put a new set of GoodYear 31x13s on Red Alert a while back...compound is a D-5 I believe? They said as heavy as the car is, it needs the harder compund...anyway, does anyone have any guesses where we need to be pressure-wise? He's been running it at 8-9psi (on a recommendation from someone else), but I think it's too low...looks to me like the tires are cupped in the center and need more air (according to the contact patch). I'll have to say, for a heavy car leaving off the foot brake, it's been dead consistent so far in the short times (1.69-1.71)... Any help is appreciated!!!! __________________ 69 Pure/Stock Yenko Camaro 11.73 @ 118

07-17-2008, 01:36 PM	#2
Bob Verwold Senior Member Join Date: Jul 2007 Location: Fayetteville Ohio Posts: 656 Likes: 0 Liked 0 Times in 0 Posts	Re: Another tire pressure question Thats the same tire I run and I run them at 101/2 lbs, car weighs 3020 but the car hooks good if this helps. Started out at 6 and kept adding air until the car started to fall off then backed off a1/4lb.................

07-17-2008, 02:01 PM	#3
Chevy454 Junior Member Join Date: Sep 2002 Location: Alton, Missouri Posts: 84 Likes: 0 Liked 0 Times in 0 Posts	Re: Another tire pressure question Ok...kinda what I was thinking, but it's been a couple cars ago since I've raced anything with stickies regularly. Quick question: with this D-5 compound, are we gonna need to boil these things in the burnout box before each run to get them to hook? Also, is looking at the contact patch from a tire a good indicator or correct pressure, or do I just need to worry about what the timers tell me? Looks like we've got about 1,000+ pounds on your car, though! Need to get to the scales, but I'm sure an original body/paint/interior '70 LS6 Chevelle with automatic, power windows, and even rear window defrost ain't gonna be a lightweight! She might not be "fat", but she's for sure "big boned"! LOL!! __________________ 69 Pure/Stock Yenko Camaro 11.73 @ 118

07-17-2008, 03:06 PM	#4
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,445 Likes: 614 Liked 1,919 Times in 576 Posts	Re: Another tire pressure question That sounds a little low for that heavy of a car unless you have them mounted on a narrow wheel. I would start out around 11 lbs and check the contact pattern. The more even the pattern the longer the tires will work good for you. That even seems like a sall tire for that type of car. Usually the big block cars like a taller tire. __________________ Mike Pearson 2485 SS