1/4 Mile Tire Pressures

[scottiec]

Hey Everyone!

Been a long time since I have been on here. Mainly because I have been driving my car!! I just crossed 4000 miles I am still smiling. It looks like I will be potentially running the car down the 1/4 mile on Saturday. It will be a little chilly out but wanted to get some advice on tire pressures.

I am running the 315 Nitto 555 G2's. They are a few years old and not nearly as sticky as they used to be (not that they were ever THAT sticky). I currently run around town with 22ish psi in them. For those that have the experience, what would you suggest dropping them to?

Thanks!!
Scottie

[Jeff Kleiner]

My experience is somewhat limited but I've been down the 1/4 more than a few times. They aren't a drag tire so I'd leave them at your street pressure. Unless they've really laid a lot of "glue" on the track you aren't going to get a hard hook. That doesn't mean that you won't have fun! Let us know how it goes :cool:

Jeff

[scottiec]

Thanks Jeff. I'm still going to do a solid burnout, because they are cool, obviously. In reality, just a quick spin of them to clear any dirt off.

[GoDadGo]

Unlike Sir Jeffski I like going straight because I still don't know how to turn left or right yet.
With a street tire, do a short burn out on a flat level street and check out your tire's contact patch.
Overinflation will yield a darker mark in the center while underinflation will yield darker marks on the sides.
I'm running 285/40-17's Nitto 555's on 10" wide wheels so 19-20 pounds of pressure gives me the most even marks.
With that said, try this practice with your 315's to see what pressure yields the most consistent marks on the pavement.
This practice seems to work best with radial tires since they don't grow nearly as much as a traditional bias-ply drag slick.

Good Luck & Have A Great Day At The Drag Strip!

[RoadRacer]

Unlike Sir Jeffski I like going straight because I still don't know how to turn left or right yet.
With a street tire, do a short burn out on a flat level street and check out your tire's contact patch.
Overinflation will yield a darker mark in the center while underinflation will yield darker marks on the sides.
I'm running 285/40-17's Nitto 555's on 10" wide wheels so 19-20 pounds of pressure gives me the most even marks.
With that said, try this practice with your 315's to see what pressure yields the most consistent marks on the pavement.
This practice seems to work best with radial tires since they don't grow nearly as much as a traditional bias-ply drag slick.

Good Luck & Have A Great Day At The Drag Strip!

or just buy a temperature gun and check temps across the tire - cheaper than leaving rubber everywhere ;)

[scottiec]

I think GoDadGo's idea is wayyyyy more fun. ha!

[GoDadGo]

or just buy a temperature gun and check temps across the tire - cheaper than leaving rubber everywhere ;)

Road Racer,

Sorry, but you missed the point completely.
Getting the tires to best contact the pavement is paramount to planting them.
A couple of short burnout or even an aggressive dry hop will paint the picture that needs to be seen.

Steve

[GoDadGo]

I think GoDadGo's idea is wayyyyy more fun. ha!

Especially When Naked!

No, Not Me, The Car Silly!

https://youtu.be/PCngiKoopkA

[NAZ]

Y'all living on the other side of the country are lucky as some of you find tracks that'll let you run. Out west we have NHRA sanctioned tracks that force us to follow the rules even during Friday Night Run What You Brung events so I have a host of things I have to go through to get my car certified and pass tech. Now I have to install OEM style fenders before NHRA will re-cert my roll cage again. Like somehow adding some fiberglass fenders renders my car safer than it was three-years ago when the NHRA chassis inspector certified it.


Have fun at the strip and be safe. I suggest you DO NOT drive through the water box or burn-out -- simply drive around the water box and stage. Your wide front tires will carry water all the way to the starting line that your rear tires have to drive through. You won't likely gain anything doing a burn-out on street tires, harder street tire compound is not that affected by heat. And don't fret too much about tire pressure on radial street tires -- they won't hold much HP no matter what you do. Easier to feather the clutch and launch at a lower RPM than try to dial in street tires. If you don't foolishly blow them off from the get-go and keep your foot into it, past about 20'-25' they should hook with moderate power (400-500 HP) and then you can pour on the power the rest of the way to the big end. Once they break loose, they will take a long time to hook again unless you pedal it. Once they hook again, it takes a bunch of power to break them loose again. So don't break them loose at the launch and you'll have a quicker run even if your launch seems slow.

STAGING TIPS: Once you light the Pre-Stage, creep slowly until the Stage light just lights then stop and that'll give you enough set-back you won't red light. Do this the exact same way and at the same creep speed every time. Then once your opponent is staged, focus intently on the bottom bulb to the exclusion of everything else in your world and launch as soon as you see the last yellow lit -- if you wait for green your gonna be very late.

[Railroad]

If the track is not using LED lamps and your adrenaline is pumping you be able to see the last yellow come on and go off. Fine tuning your launch to the lamps illumination or waning you can cut some good RTs. Have fun.

[scottiec]

Y'all living on the other side of the country are lucky as some of you find tracks that'll let you run. Out west we have NHRA sanctioned tracks that force us to follow the rules even during Friday Night Run What You Brung events so I have a host of things I have to go through to get my car certified and pass tech. Now I have to install OEM style fenders before NHRA will re-cert my roll cage again. Like somehow adding some fiberglass fenders renders my car safer than it was three-years ago when the NHRA chassis inspector certified it.


Have fun at the strip and be safe. I suggest you DO NOT drive through the water box or burn-out -- simply drive around the water box and stage. Your wide front tires will carry water all the way to the starting line that your rear tires have to drive through. You won't likely gain anything doing a burn-out on street tires, harder street tire compound is not that affected by heat. And don't fret too much about tire pressure on radial street tires -- they won't hold much HP no matter what you do. Easier to feather the clutch and launch at a lower RPM than try to dial in street tires. If you don't foolishly blow them off from the get-go and keep your foot into it, past about 20'-25' they should hook with moderate power (400-500 HP) and then you can pour on the power the rest of the way to the big end. Once they break loose, they will take a long time to hook again unless you pedal it. Once they hook again, it takes a bunch of power to break them loose again. So don't break them loose at the launch and you'll have a quicker run even if your launch seems slow.

STAGING TIPS: Once you light the Pre-Stage, creep slowly until the Stage light just lights then stop and that'll give you enough set-back you won't red light. Do this the exact same way and at the same creep speed every time. Then once your opponent is staged, focus intently on the bottom bulb to the exclusion of everything else in your world and launch as soon as you see the last yellow lit -- if you wait for green your gonna be very late.


Naz,

This is super helpful. They are an NHRA track. I am going to send you a PM and see if you have some time for me to pick your brain.

[scottiec]

If the track is not using LED lamps and your adrenaline is pumping you be able to see the last yellow come on and go off. Fine tuning your launch to the lamps illumination or waning you can cut some good RTs. Have fun.

So you're saying I need to keep my eyes open when I'm doing this? LOL

[BEAR-AvHistory]

Some white liquid shoe polish across the tread is an easy inflation pressure indicator. As GoDadGo said if the middle is warn off too much air, outer edges warn not enough air. Get a balance the check the tires roll over up the outer edges. Fine tune to balance all three, will have to make tradeoffs as to how the tire is used.

https://cimg5.ibsrv.net/gimg/acurazine.com-vbulletin/580x435/80-rear_0404bdc70e2f3758bb0335ac4eb5c538dcf01100.jpg

https://cimg4.ibsrv.net/gimg/acurazine.com-vbulletin/580x435/80-front_5e3bd6dd86ab942c8532f0b76996fa54e8559f20.jpg

[Jeff Kleiner]

...And don't fret too much about tire pressure on radial street tires -- they won't hold much HP no matter what you do. Easier to feather the clutch and launch at a lower RPM than try to dial in street tires. If you don't foolishly blow them off from the get-go and keep your foot into it, past about 20'-25' they should hook with moderate power (400-500 HP) and then you can pour on the power the rest of the way to the big end. Once they break loose, they will take a long time to hook again unless you pedal it. Once they hook again, it takes a bunch of power to break them loose again. So don't break them loose at the launch and you'll have a quicker run even if your launch seems slow...




Listen to NAZ; he just described EXACTLY what I found when I ran mine with 180 treadwear street tires on a basically unprepped track! I blew them off the first couple of passes and got much better results by just rolling into it once moving.

https://thefactoryfiveforum.com/attachment.php?attachmentid=156256&d=1636744293

Cheers!

Jeff




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