Tire pressure on street radials 4 1/8 mile?

Big Bopper · 07-22-2000, 12:37 PM

What tire pressure should I be running at the srip? My tires are just cheeep and nastys.Is lowering the tire pressure a benefit on radials like mine?
Thanks for any help.

buddha · 07-23-2000, 12:32 AM

Everything Ive ever heard about radial tires it to run them at the suggested PSI. Their designed to run at this pressure and puts the best contact patch on the surface. Any normal street tire wont hook worth a damn. Its like driving on wet pavement.

07-24-2000, 10:28 AM

I would experiment with the pressures. Usually, on a regular radial, I would run around 23 to 24 psi. Try this method - find a clean piece of asphalt somewhere away from any people/cops. Do a burnout & take a look at the marks. If they are an even black strip across the width, reduce the pressure by 1 or 2 psi. Try another burnout. If they are still even, reduce pressure again. Try this until the black marks start to fade in the middle. At this point, go back to the previous psi setting. This will give you your ultimate contact patch at the lowest tire pressure, which helps 'crinkle' the sidewall (albeit only a little with radials) & helps traction alot.

------------------
'91LX coupe.3.73's,alum dr shaft,subs,upper & lower ctrl arms,90/10's
1 5/8 long tubes,2 1/2" exh-off road H-pipe,ported stock t-body,ProM-77mm mass air
cut & welded ported cobra intake,ported edelbrock heads,B303cam, 1.72 rr's,36lb inj's,
tremec, & a Paxton NOVI 2000!!!
11.43 @ 122 mph on Nitto Drag Radials (245/50/16)
11.25 @ 127 on BFG Drag Radials (275/60/15)

cometbfx · 07-24-2000, 12:44 PM

...wouldn't it make more sense, and not to mention safer, to just go buy a set of correct tires for the application you want, ie. drag strip? Get a set of DOT slicks, and be done with it. The last thing you want, going through the traps at high speeds is instability because of incorrect tire pressure. Man, it's just not worth it!

------------------
HeadsUp4ever!

07-24-2000, 04:13 PM

Actually, cometbfx, I race in a radial tire class, & have raced in a class where even drag radials weren't allowed. IMHO, an aired down radial is more stable than an aired down bias ply slick or cheater slick. You air those down to the 10 psi range to race at the track for optimal traction. That's seems even scarier to me!
My 275/60/15 BFG drag radials at 12psi still felt stable at 128.61 mph (which is what I ran this past Saturday testing!)

cometbfx · 07-24-2000, 04:56 PM

I'm glad to hear that they are stable at those speeds. Maybe they are better than regular slicks. I should look into trying them. Sounds like our top end in the 1/4 mile is about the same. The part that scared me was the comment "...are just cheep and nastys..." I don't know how you feel about it, but at those speeds, I think any compromise to safety is nuts! I think I would want the guy next to me going through the traps to have the highest quality tire built for the application he is using.
p.s. at times our slicks are at 8....but they've been designed for that. You are right, an "aired-down" bias-ply slick is less than optimum at higher speeds.
Also, I see on your sig, you list both as "drag" radials....Big didn't classify his as "drag", just "...cheeep..."
(what's the weight of ur '91 ready to race?)

------------------
HeadsUp4ever!

07-24-2000, 05:11 PM

Hey comet, you're right, I forgot that he said cheap 'n nasties. Those might be scary. My car at race weight with me in it & 1/2 tank of fuel is 3180 lbs. Let me know if you ever come up to Cayuga. I go there to test & tune sometimes.

cometbfx · 07-24-2000, 05:42 PM

Thanks for the invite. We love Cayuga, they treat us like royality there. And they know how to put on a good show. Are they runnin' a box 10.90 elim? Have not been there in awhile. Our longer travels have taken us to Thompson and Columbus, Oh. lately. Have you heard about the new "Super-Plex" at NF, Ont? Supposed to be ready for next year. Can't wait. Heard it will be IHRA (our favorite), and it's a LOT closer than Cayuga. Just wondering if that will cancel the IHRA sanctioning at Empire Dragway in Leicester NY, as they are kinda close. Some day I gotta talk to you about the Paxton.....hmmmmm, I've been thinking about one.
Let me know quite a bit in advance, if you can, when you're going to Cayuga next. Maybe we'll cruise up and have a blast!
p.s. You run boxes?

------------------
HeadsUp4ever!

07-25-2000, 07:19 AM

Yes, I've heard about Niagra Falls, but it's all been hearsay, nothing in print. I hope that it's true! It may put a damper on Cayuga, it's awful close to them also!. I don't run in open comp or bracket racing I race strictly heads up, in radial tire classes this year. I don't know any particulars on Cayuga's classes. Maybe check their website out at www.cayugadragway.com . I'll let you know when we go to cayuga next.

07-22-2000, 12:37 PM	#1
Big Bopper Registered Member Join Date: Jun 2000 Location: Sechelt, B.C., Canada Posts: 200	Tire pressure on street radials 4 1/8 mile? What tire pressure should I be running at the srip? My tires are just cheeep and nastys.Is lowering the tire pressure a benefit on radials like mine? Thanks for any help.

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07-23-2000, 12:32 AM	#2
buddha Registered Member Join Date: Feb 2000 Location: Washington, MO Posts: 327	Everything Ive ever heard about radial tires it to run them at the suggested PSI. Their designed to run at this pressure and puts the best contact patch on the surface. Any normal street tire wont hook worth a damn. Its like driving on wet pavement.

07-24-2000, 10:28 AM	#3
SisuStang Guest Posts: n/a	I would experiment with the pressures. Usually, on a regular radial, I would run around 23 to 24 psi. Try this method - find a clean piece of asphalt somewhere away from any people/cops. Do a burnout & take a look at the marks. If they are an even black strip across the width, reduce the pressure by 1 or 2 psi. Try another burnout. If they are still even, reduce pressure again. Try this until the black marks start to fade in the middle. At this point, go back to the previous psi setting. This will give you your ultimate contact patch at the lowest tire pressure, which helps 'crinkle' the sidewall (albeit only a little with radials) & helps traction alot. ------------------ '91LX coupe.3.73's,alum dr shaft,subs,upper & lower ctrl arms,90/10's 1 5/8 long tubes,2 1/2" exh-off road H-pipe,ported stock t-body,ProM-77mm mass air cut & welded ported cobra intake,ported edelbrock heads,B303cam, 1.72 rr's,36lb inj's, tremec, & a Paxton NOVI 2000!!! 11.43 @ 122 mph on Nitto Drag Radials (245/50/16) 11.25 @ 127 on BFG Drag Radials (275/60/15)

07-24-2000, 12:44 PM	#4
cometbfx Registered Member Join Date: Jun 2000 Location: NY shores of Lake Erie Posts: 241	...wouldn't it make more sense, and not to mention safer, to just go buy a set of correct tires for the application you want, ie. drag strip? Get a set of DOT slicks, and be done with it. The last thing you want, going through the traps at high speeds is instability because of incorrect tire pressure. Man, it's just not worth it! ------------------ HeadsUp4ever!

07-24-2000, 04:13 PM	#5
SisuStang Guest Posts: n/a	Actually, cometbfx, I race in a radial tire class, & have raced in a class where even drag radials weren't allowed. IMHO, an aired down radial is more stable than an aired down bias ply slick or cheater slick. You air those down to the 10 psi range to race at the track for optimal traction. That's seems even scarier to me! My 275/60/15 BFG drag radials at 12psi still felt stable at 128.61 mph (which is what I ran this past Saturday testing!)

07-24-2000, 04:56 PM	#6
cometbfx Registered Member Join Date: Jun 2000 Location: NY shores of Lake Erie Posts: 241	I'm glad to hear that they are stable at those speeds. Maybe they are better than regular slicks. I should look into trying them. Sounds like our top end in the 1/4 mile is about the same. The part that scared me was the comment "...are just cheep and nastys..." I don't know how you feel about it, but at those speeds, I think any compromise to safety is nuts! I think I would want the guy next to me going through the traps to have the highest quality tire built for the application he is using. p.s. at times our slicks are at 8....but they've been designed for that. You are right, an "aired-down" bias-ply slick is less than optimum at higher speeds. Also, I see on your sig, you list both as "drag" radials....Big didn't classify his as "drag", just "...cheeep..." (what's the weight of ur '91 ready to race?) ------------------ HeadsUp4ever!

07-24-2000, 05:11 PM	#7
SisuStang Guest Posts: n/a	Hey comet, you're right, I forgot that he said cheap 'n nasties. Those might be scary. My car at race weight with me in it & 1/2 tank of fuel is 3180 lbs. Let me know if you ever come up to Cayuga. I go there to test & tune sometimes.

07-24-2000, 05:42 PM	#8
cometbfx Registered Member Join Date: Jun 2000 Location: NY shores of Lake Erie Posts: 241	Thanks for the invite. We love Cayuga, they treat us like royality there. And they know how to put on a good show. Are they runnin' a box 10.90 elim? Have not been there in awhile. Our longer travels have taken us to Thompson and Columbus, Oh. lately. Have you heard about the new "Super-Plex" at NF, Ont? Supposed to be ready for next year. Can't wait. Heard it will be IHRA (our favorite), and it's a LOT closer than Cayuga. Just wondering if that will cancel the IHRA sanctioning at Empire Dragway in Leicester NY, as they are kinda close. Some day I gotta talk to you about the Paxton.....hmmmmm, I've been thinking about one. Let me know quite a bit in advance, if you can, when you're going to Cayuga next. Maybe we'll cruise up and have a blast! p.s. You run boxes? ------------------ HeadsUp4ever!

07-25-2000, 07:19 AM	#9
SisuStang Guest Posts: n/a	Yes, I've heard about Niagra Falls, but it's all been hearsay, nothing in print. I hope that it's true! It may put a damper on Cayuga, it's awful close to them also!. I don't run in open comp or bracket racing I race strictly heads up, in radial tire classes this year. I don't know any particulars on Cayuga's classes. Maybe check their website out at www.cayugadragway.com . I'll let you know when we go to cayuga next.