|
07-16-2008, 11:07 AM | #1 |
Junior Member
Join Date: Oct 2004
Location: east brunswick, new jersey
Posts: 62
Likes: 0
Liked 0 Times in 0 Posts
|
Rear tire air pressure
this feels like a really stupid question. what should air pressure be in the rear tires?
i know all cars are different, some like higher than lower and that the type of car matters, as does weight. but, my question is for me and my car. its a 9.6 full body camaro weights 3050 with me in it, i got 8 lbs in my big tire car. my 60 ft times however have no reason to them. i've been at low as 1.31 for the first run of the day and i've had 1.31 as the last run of the day. unfortunally i've also had a few 1.35 and some 1.37. this as we know is death at the finish line. your either holding a ton, or you hope that your oppounet had like a .110 r/t since you don't have a pray of running the number.
__________________
S/ST 1739 Carlos Mendes |
07-16-2008, 04:43 PM | #2 | |
Member
Join Date: Jun 2008
Location: League City, Texas
Posts: 243
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
Quote:
|
|
07-17-2008, 10:09 AM | #3 |
Junior Member
Join Date: Oct 2004
Location: east brunswick, new jersey
Posts: 62
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
thanks bobby
but, thats not what i mean by big tire. i ran those pounds also when i had the smaller tire. no my question was for door slammers weighting 3000 lbs with 32X14.0X15 i got 8lbs. some folks say i should have less, but the car weights so much. your thoughts?????????
__________________
S/ST 1739 Carlos Mendes |
07-17-2008, 11:09 AM | #4 |
Member
Join Date: Jun 2008
Location: League City, Texas
Posts: 243
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
OH, they are big for me, LOL. My brother runs something like a 14x32 and runs 9, I think. I usually don't check his tires. His wife does that for him. He also runs a footbrake car and M/T tires.
|
07-17-2008, 11:11 AM | #5 |
Member
Join Date: Dec 2006
Location: Indy
Posts: 422
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
You are close, given the variances of tire gauges at low pressures, you could run anywhere from 6 1/2 to 8 1/2 and be "correct"....it also matters whether it is a stiff sidewall, the front/rear weight balance, and how much it gets up on the rear tires for the launch.
If you aren't wadding the tires on the launch, they leave a full footprint, and wear even across the tread section, you have it right. Sounds like you are having a hot track / tire compound issue to me. I ease up on the burnouts when the track is hot, as well as running a "medium-hard" (Goodyear D-4A) compound for that purpose. When the track temps exceed 110-120 degrees, I do a dragster type burnout and roll to the line. |
07-17-2008, 03:27 PM | #6 |
Junior Member
Join Date: Oct 2004
Location: east brunswick, new jersey
Posts: 62
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
hi dave
no i don't have the corage to do a dragters type buntout. with no line lock at all, i'm not sure it would clean off the tires enough and "hook" on the hit. sometimes i'll do a shorter burn out and roll forward. its just those 60 fts not being consistant enough for my liking. just was wondering if pressure helped one way or the other. as for the foot print yea i know about that one to. seems smooth right across, its about time to rotate them i got about 20 runs on them now, time to flip them over
__________________
S/ST 1739 Carlos Mendes |
07-21-2008, 12:59 PM | #7 |
Junior Member
Join Date: Nov 2004
Location: Virginia, USA
Posts: 46
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
Don't forget to measure the rollout while you're rotating them.Joe.
|
07-21-2008, 02:18 PM | #8 |
Junior Member
Join Date: Oct 2004
Location: east brunswick, new jersey
Posts: 62
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
Why ?????
__________________
S/ST 1739 Carlos Mendes |
07-22-2008, 12:12 AM | #9 |
Junior Member
Join Date: Feb 2008
Location: Le Claire, IA
Posts: 29
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
I ran 8-10.5 on my 14.5 x 32's on my 3200# 65 442 clone running as quick as 9.90.
If you think you're 60's are inconsistent , try radial slicks! On a poorly prepped track my 30 x10.5 radials will 60' Either 1.50 or 1.80 ,& not much in between. Now on a decent track they'll be 1.50 all day!
__________________
Jeff Smith S/ST- Pro/ET 5102 Creating the streetable S/ST Olds |
07-22-2008, 11:15 AM | #10 |
Junior Member
Join Date: Jan 2006
Location: Maryland
Posts: 81
Likes: 0
Liked 0 Times in 0 Posts
|
Re: Rear tire air pressure
Carlos, the tires can be a differen't circumfrence even though they are the same size so measuring the rollout of each tire will tell ou this. Also in a 2500 lb car and 2700 lb car i run 6.5 to 7.0 In a 3100lbs car We run 7.5. You need to run as high as pressure as you can w/o spinning or being inconsistent. So i would start out around 7.5 and go up from there. And it does depend on the gauge, but i use two of the 80$ jegs gauges and both of them read exactly the same.
__________________
87 Cavalier, 92 Corvette, 72 Nova, 68 Firebird |
|
|