1TONY1
Enthusiast
Road Atlanta, stock pilots, will be in the touring group this time so I don't think we will be running anywhere near the cars capability. tia Tony
Road course tire pressure ??
- Thread starter 1TONY1
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SoCal Rebell
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by 1TONY1:
Road Atlanta, stock pilots, will be in the touring group this time so I don't think we will be running anywhere near the cars capability. tia Tony
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On stock Pilots a good starting point COLD is 32 psi front and 30 psi rear. As soon as your first session is done immediately take tire pressures. Fronts should be between 40-42 psi HOT and rears should be round 37-38 psi HOT. If going clockwise the front left will probably be a pound higher then the right because it takes more pounding.
Road Atlanta, stock pilots, will be in the touring group this time so I don't think we will be running anywhere near the cars capability. tia Tony
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On stock Pilots a good starting point COLD is 32 psi front and 30 psi rear. As soon as your first session is done immediately take tire pressures. Fronts should be between 40-42 psi HOT and rears should be round 37-38 psi HOT. If going clockwise the front left will probably be a pound higher then the right because it takes more pounding.
MtHam ACR
Enthusiast
I agree with Ron's starting pressures, or maybe a lb or two lower. But in my experience you aren't going to see 10lbs difference with a hot tire.
I try and shoot for the following pressures hot: 35R, 36F
6-7 lbs is about all the hot/cold difference I've ever seen, but maybe Ron pushes the car harder. IMHO, 40-42 hot is too high. Gavin (HEEEEPS) had pretty good results at Laguna last weekend from an adjustment down to ~35-36 hot from the 40-42 range.
Eric
I try and shoot for the following pressures hot: 35R, 36F
6-7 lbs is about all the hot/cold difference I've ever seen, but maybe Ron pushes the car harder. IMHO, 40-42 hot is too high. Gavin (HEEEEPS) had pretty good results at Laguna last weekend from an adjustment down to ~35-36 hot from the 40-42 range.
Eric
toddt
Enthusiast
Why not run at 29psi all around like dodge recommends?
Chuck 98 RT/10
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by toddt:
Why not run at 29psi all around like dodge recommends?
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Tony is running in the touring group which isn't near the speeds as race groups. For that reason 29psi is probably ok, 34 front 32 back won't hurt. But still check them after every run.
Why not run at 29psi all around like dodge recommends?
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Tony is running in the touring group which isn't near the speeds as race groups. For that reason 29psi is probably ok, 34 front 32 back won't hurt. But still check them after every run.
We are all in the same ballpark, but I would recommend you stay in the 34-35 range in the front, and 30 in the rear, based on your tire size ( I am assuming 275s on front ). Even in the touring group, the front end pushes, especially with the standard size tire. Have fun and keep the cool head coming down turn 12!
Serious Eric
Enthusiast
What kind of pyrometer temps are you guys seeing? I haven't gone that route yet, but I know the tire air temp was hot as hell right after a run. I was seeing 40-42 psi hot and decided that was too much so I went to let some out using the tip of the valve stem cap and that d@mn air comin outta there literally burned my fingers. I mean it must've been a good bit over 200 F!
What's normal for internal air temps after a good beating? ... just curious. (street tires)
What's normal for internal air temps after a good beating? ... just curious. (street tires)
Fast Freddy
Enthusiast
if a car is pushing in the turns aka as understeer. you will need to run lower tire pressures in the front to gain more grip. i would run 31 psi in the rear and 29 psi in the front cold.
SoCal Craig
Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by FAST FREDDY:
if a car is pushing in the turns aka as understeer. you will need to run lower tire pressures in the front to gain more grip. i would run 31 psi in the rear and 29 psi in the front cold.
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I thought it was the other way around... more pressure in the front to reduce understeer. That's the way it is on my Porsche anyway. Doesn't it have something to do with reduced slip-angles (less sidewall flex) with more pressure?
if a car is pushing in the turns aka as understeer. you will need to run lower tire pressures in the front to gain more grip. i would run 31 psi in the rear and 29 psi in the front cold.
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Gavin
Enthusiast
Eric is right, in my particular case, running Pilot Sports at Laguna Seca Memorial Weekend. I settled on Hot Pressures of 35 Rear, 37 Front.
Up until Eric had me change the pressures I ad always kept Pressures at 40 front, 39 rear.
With the lower pressures I picked up more grip and was able to run with Eric - although I think he was going easy on me - I have to fess up, for a moment I was distracted by a sheep and went two wheels off in turn 6.
Up until Eric had me change the pressures I ad always kept Pressures at 40 front, 39 rear.
With the lower pressures I picked up more grip and was able to run with Eric - although I think he was going easy on me - I have to fess up, for a moment I was distracted by a sheep and went two wheels off in turn 6.
MtHam ACR
Enthusiast
Ever wondered what makes those guys from New Zealand so fast?
Gavin's car was spotted with this dangling from a stick out in front of his bumper!
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Gavin's car was spotted with this dangling from a stick out in front of his bumper!
SSpeed Racer
Enthusiast
Eric what kind of times where you running at Laguna??
I run 32F and 30R cold and 42F 35R Hot.
Although the right front got up to 48 HOT a few times!!
I was running 1.46 and 1.47s at these temps with Stock Michelins and 275's up front.
I run 32F and 30R cold and 42F 35R Hot.
Although the right front got up to 48 HOT a few times!!
I was running 1.46 and 1.47s at these temps with Stock Michelins and 275's up front.
Gavin
Enthusiast
Eric, Now thats awful close to Mutton - personally I prefer "Lamb" !!!!!
"Rebel" we were running 1.53 in light traffic - did not really get any clear laps.
I ran that same weekend when you were here at Laguna earlier this year and you were awfully quick. I have no doubts if you were running with us this Memorial Weekend we would have gotten a sound whupping.
Congrates on your efforts recently - followed the reporting with great interest - look forward to seeing you at a track sometime soon.
The most interesting part of the weekend, seperate from the incident with the sheep, was watching Bruce in his modified GTS pass the GT2 Porsche - GT2 was not up to the Viper pace at all.
We understand he made a call to Germany!!
Gavin
"Rebel" we were running 1.53 in light traffic - did not really get any clear laps.
I ran that same weekend when you were here at Laguna earlier this year and you were awfully quick. I have no doubts if you were running with us this Memorial Weekend we would have gotten a sound whupping.
Congrates on your efforts recently - followed the reporting with great interest - look forward to seeing you at a track sometime soon.
The most interesting part of the weekend, seperate from the incident with the sheep, was watching Bruce in his modified GTS pass the GT2 Porsche - GT2 was not up to the Viper pace at all.
We understand he made a call to Germany!!
Gavin
MtHam ACR
Enthusiast
John wrote <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I run 32F and 30R cold and 42F 35R Hot.
Although the right front got up to 48 HOT a few times!!
I was running 1.46 and 1.47s at these temps with Stock Michelins and 275's up front.<HR></BLOCKQUOTE>
Hey John, a buddy of mine speaks highly of your driving ability, Rick Bailey (black 01 Z06) says you guys hooked-up earlier this year and had a good go.
I was measuring pressures after a cool-down lap, and was getting push when towards the end of the session with these pressures -- I was actually thinking about going a bit lower to give the tire a bit more bite (?). It sounds like with all the skating (potential), you're doing a lot of steering with your right foot?
Your times speak for themselves, help me understand why higher front pressures work better for you.
[excuse] I came from the Mustang/Cobra world and have really only had the car on the track a couple of weekends -- I'm still trying to figure out how to drive the car. [/excuse]
Gavin, 1:53?
Is that all?
That sheep musta been creating some hellacious drag!
Did you hear Luc say that GT2 pulled him on the straight? He's getting well north of 500HP out of that mustang.
Eric
Although the right front got up to 48 HOT a few times!!
I was running 1.46 and 1.47s at these temps with Stock Michelins and 275's up front.<HR></BLOCKQUOTE>
Hey John, a buddy of mine speaks highly of your driving ability, Rick Bailey (black 01 Z06) says you guys hooked-up earlier this year and had a good go.
I was measuring pressures after a cool-down lap, and was getting push when towards the end of the session with these pressures -- I was actually thinking about going a bit lower to give the tire a bit more bite (?). It sounds like with all the skating (potential), you're doing a lot of steering with your right foot?
Your times speak for themselves, help me understand why higher front pressures work better for you.
[excuse] I came from the Mustang/Cobra world and have really only had the car on the track a couple of weekends -- I'm still trying to figure out how to drive the car. [/excuse]
Gavin, 1:53?
Is that all?
That sheep musta been creating some hellacious drag!
Did you hear Luc say that GT2 pulled him on the straight? He's getting well north of 500HP out of that mustang.
Eric
luc
Enthusiast
Yes,the German horses must be a LOT bigger than the US horses.
from what the driver told me the GT2 is rated at 465 for both hp and torque.
Since my 65 shelby/Mustang weight 2700# and crank out about 525HP and that I pull away VERY easly from vipers,I will think that the GT2 (at least this car)is more like 550hp.
Eric,
you had some nice lines at laguna and you drove the viper very smoothly.
John,
you need to put some Hoosiers on your car and come play with me and my 69 Mustang (1.41) on 275 Hoosiers.
From what I heard of you driving lately,I am going to have to watch my rear view mirror to make sure that you don't run me over,or forget about my old muscle cars and run my Roush T/A !!!.
Gavin.
The GT2 driver (he used to drive/race a 240z)was really learning his car,going from a front engine to a rear engine is a big diffence,once he get used to it,he will be way faster.
Luc.00GTS
from what the driver told me the GT2 is rated at 465 for both hp and torque.
Since my 65 shelby/Mustang weight 2700# and crank out about 525HP and that I pull away VERY easly from vipers,I will think that the GT2 (at least this car)is more like 550hp.
Eric,
you had some nice lines at laguna and you drove the viper very smoothly.
John,
you need to put some Hoosiers on your car and come play with me and my 69 Mustang (1.41) on 275 Hoosiers.
From what I heard of you driving lately,I am going to have to watch my rear view mirror to make sure that you don't run me over,or forget about my old muscle cars and run my Roush T/A !!!.
Gavin.
The GT2 driver (he used to drive/race a 240z)was really learning his car,going from a front engine to a rear engine is a big diffence,once he get used to it,he will be way faster.
Luc.00GTS
Gavin
Enthusiast
Luc - we need to get you and John on the same track AT THE SAME TIME AND IN EQUAL CARS- time to get that viper out of its cobwebs and to the track - watching you BOTH go at it would be very entertaining for us track rookies.
I concur - Eric is very good for a guy that "claims" he has only had his car on the track twice - he is a quick learner though..... he was most interested in learning about......SHEEP!
I concur - Eric is very good for a guy that "claims" he has only had his car on the track twice - he is a quick learner though..... he was most interested in learning about......SHEEP!
SSpeed Racer
Enthusiast
Gavin, I ran with Luc in January this year at Laguna and got to follow him around for a while he had me pushing my stock tires to the limit!!! The only time I could get on his bumper was when he slowed down for the Sound box!!!
He is an excellent driver. I am up for the challenge.
Now where can I get another 100 hp to compete?
What's up with the Sheep thing?? I thought those where only popular in Montana???
Luc, Yes I have had some real issues with my stock brake system so...I am getting rid of them today!!! I should not have any more brake problems the car is in the shop now getting the New Stoptech system on all four corners. I will be testing them on Sunday at Willow Springs with NASA should be fun.
Anyone have a set of Hoosiers I can borrow??? I would like to
run in the high 1.29 at Willow. That would be awesome.
MtHAM, No matter what you do the car is going to push with 275's up front. I always thought the way you do ...lower the pressure more tire on the ground. But it does not seem to work that way. Next time your out try lowering the pressure and see what happens it will create more understeer than before. On a clockwise track I always drop the pressure 1 lb on the left front.... but try it stay consistent with my pressures not going over 42 lbs in front. On counterclockwise I do just the opposite.
Try not to concentrate on tire pressures to much. Feel the car.. Quote from one of the best Viper drivers I know. PMUMford "I don't even keep track of them"!
I did a lot of left foot trailbraking at Laguna to help steer the car around the turns..otherwise trying to keep the speeds up that I was going I would not have completed the turn and run off.
Hope this helps.
He is an excellent driver. I am up for the challenge.
Now where can I get another 100 hp to compete?
What's up with the Sheep thing?? I thought those where only popular in Montana???
Luc, Yes I have had some real issues with my stock brake system so...I am getting rid of them today!!! I should not have any more brake problems the car is in the shop now getting the New Stoptech system on all four corners. I will be testing them on Sunday at Willow Springs with NASA should be fun.
Anyone have a set of Hoosiers I can borrow??? I would like to
run in the high 1.29 at Willow. That would be awesome.
MtHAM, No matter what you do the car is going to push with 275's up front. I always thought the way you do ...lower the pressure more tire on the ground. But it does not seem to work that way. Next time your out try lowering the pressure and see what happens it will create more understeer than before. On a clockwise track I always drop the pressure 1 lb on the left front.... but try it stay consistent with my pressures not going over 42 lbs in front. On counterclockwise I do just the opposite.
Try not to concentrate on tire pressures to much. Feel the car.. Quote from one of the best Viper drivers I know. PMUMford "I don't even keep track of them"!
I did a lot of left foot trailbraking at Laguna to help steer the car around the turns..otherwise trying to keep the speeds up that I was going I would not have completed the turn and run off.
Hope this helps.
SSpeed Racer
Enthusiast
Are any of you going to be at Willow Springs this weekend???
Inquiring minds want to know???
Inquiring minds want to know???
K Adelberg
Enthusiast
Luc,
Don't ************ up there to your house and blow the cobwebs of that Mustang of yours. You are a great driver and I had a blast with you over a year ago, until my rear brakes locked and put out the James Bond smoke screen.
When are you coming back down this way? Love racing with ya.
Don't ************ up there to your house and blow the cobwebs of that Mustang of yours. You are a great driver and I had a blast with you over a year ago, until my rear brakes locked and put out the James Bond smoke screen.
When are you coming back down this way? Love racing with ya.
luc
Enthusiast
Ken,
good to hear from you.
I will be racing at the California Speedway for the July 4th weekend.
It is the National Shelby Club Convention and if you like to see Cobras,Trans/Am,GT40s and GT350s racing,you should come.
Luc.00GTS
good to hear from you.
I will be racing at the California Speedway for the July 4th weekend.
It is the National Shelby Club Convention and if you like to see Cobras,Trans/Am,GT40s and GT350s racing,you should come.
Luc.00GTS
Frank Parise
VCA Venom Member
A tire is designed to produce maximum cornering traction within a range of tire slip angles. The slip angle is the angle between the direction the wheel is pointed and the direction the wheel is actaully traveling. It is easy to think of it in terms of sidewall deflection in a turn.
If you don't push the car hard enough to get within the optimal slip angle range, you can decrease air pressure and that will increase the tire slip angles, giving more traction. This is usually what a less-experienced driver needs to do.
A more experienced driver is pushing the car hard enough to exceed the optimal slip angles, therefore he needs to add air pressure and that will reduce slip angles into the optimal range.
The confusing result is that you can reduce understeer by either increasing or decreasing tire pressures in the front. It depends on how hard your cornering force actually is.
If you don't push the car hard enough to get within the optimal slip angle range, you can decrease air pressure and that will increase the tire slip angles, giving more traction. This is usually what a less-experienced driver needs to do.
A more experienced driver is pushing the car hard enough to exceed the optimal slip angles, therefore he needs to add air pressure and that will reduce slip angles into the optimal range.
The confusing result is that you can reduce understeer by either increasing or decreasing tire pressures in the front. It depends on how hard your cornering force actually is.
MtHam ACR
Enthusiast
Frank wrote <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>The confusing result is that you can reduce understeer by either increasing or decreasing tire pressures in the front. It depends on how hard your cornering force actually is.<HR></BLOCKQUOTE>
Got it, good explanation, thanks. When I see stuff like this it never fails to pound me over the head that there is nothing instinctual about this sport -- it's a thinking man's game.
John, I'd love to hook up at Willow sometime (for the first time). But summertime is not my first choice! How about Buttonwillow in Sept for Viperdays (which one could argue is equally bad
)?
-Eric
Got it, good explanation, thanks. When I see stuff like this it never fails to pound me over the head that there is nothing instinctual about this sport -- it's a thinking man's game.
John, I'd love to hook up at Willow sometime (for the first time). But summertime is not my first choice! How about Buttonwillow in Sept for Viperdays (which one could argue is equally bad
-Eric
SSpeed Racer
Enthusiast
Eric,
Looks like it going to be a good weekend at Willow with temps only in the 80's!!! So i am going to go play Sunday!!
Buttonwillow it is. I will be there for Viper days!! Look forward to meeting you!!!
Frank great explanation on Slip angles related to tire pressures. You are right on the money! Your hands can explain it better than mine!!
Looks like it going to be a good weekend at Willow with temps only in the 80's!!! So i am going to go play Sunday!!
Buttonwillow it is. I will be there for Viper days!! Look forward to meeting you!!!
Frank great explanation on Slip angles related to tire pressures. You are right on the money! Your hands can explain it better than mine!!
SoCal Craig
Enthusiast
Frank, thanks for the explanation.
John, it was 100+ at Willow yesterday... good luck!!!
Buttonwillow for Viper Days... yea baby!!!
John, it was 100+ at Willow yesterday... good luck!!!
Buttonwillow for Viper Days... yea baby!!!
