Rear tire air pressure

Joe Sprint Bros · 07-21-2008, 12:59 PM

Don't forget to measure the rollout while you're rotating them.Joe.

BIZMANRACING · 07-21-2008, 02:18 PM

Why ?????

mrolds · 07-22-2008, 12:12 AM

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!

SlickVic · 07-22-2008, 11:15 AM

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.

BIZMANRACING · 07-22-2008, 04:18 PM

vic

so if i understand you correctly. your saying that my 60 ft wow's are probally due to spinning tires. ok if i give you that, then where can i verify it on the time slip? i have my wife at the starting line but, i don't think i can explain a "wheel slip" to her and have her look for it. i could i guess give here a cmaera and just play it back nice and slow. but, i don't think she's about that either. to her its fun to be there to watch, not to anaylze the a,b,c,'s of the sport.

so, can you see wheel spin anywhere else on the time slip to confirm it. since its to easy to say hum 1.37 instead of 1.31 the wheel s spun, guess i need to drop another half pund out of the tires.....

thanks

348 · 07-24-2008, 10:26 PM

Carlos
One of the first thing I would try would be lowering your launch rpm. The car may not 60ft as quick but it may make it more consistant. Depending on what you have for suspension shock settings also make a big difference. Every thing has to work together. When making changes, just make one at a time. On my elcamino I sometimes lower the launch as low as 3200 on a slick track.

07-21-2008, 12:59 PM	#1
Joe Sprint Bros 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	#2
BIZMANRACING 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	#3
mrolds 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	#4
SlickVic 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

07-22-2008, 04:18 PM	#5
BIZMANRACING 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 vic so if i understand you correctly. your saying that my 60 ft wow's are probally due to spinning tires. ok if i give you that, then where can i verify it on the time slip? i have my wife at the starting line but, i don't think i can explain a "wheel slip" to her and have her look for it. i could i guess give here a cmaera and just play it back nice and slow. but, i don't think she's about that either. to her its fun to be there to watch, not to anaylze the a,b,c,'s of the sport. so, can you see wheel spin anywhere else on the time slip to confirm it. since its to easy to say hum 1.37 instead of 1.31 the wheel s spun, guess i need to drop another half pund out of the tires..... thanks __________________ S/ST 1739 Carlos Mendes

07-24-2008, 10:26 PM	#6
348 Junior Member Join Date: Aug 2007 Posts: 3 Likes: 0 Liked 0 Times in 0 Posts	Re: Rear tire air pressure Carlos One of the first thing I would try would be lowering your launch rpm. The car may not 60ft as quick but it may make it more consistant. Depending on what you have for suspension shock settings also make a big difference. Every thing has to work together. When making changes, just make one at a time. On my elcamino I sometimes lower the launch as low as 3200 on a slick track. __________________ Bill Hurst S/C348H ET348H