Inside wheel lift - tire pressures?
06-03-2004, 05:32 PM
#31
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john,
i ran my hoosiers at 36 cold to get to 43 hot. the "skating" was a bit funny feeling at first, but improved as the tire was used more.
i did cord the inside of one front tire at each of the events at watkins glen that i attended last year. no problems at any other track so far.
i ran my hoosiers at 36 cold to get to 43 hot. the "skating" was a bit funny feeling at first, but improved as the tire was used more.
i did cord the inside of one front tire at each of the events at watkins glen that i attended last year. no problems at any other track so far.
06-03-2004, 05:38 PM
#32
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i punish my hoosiers. I get a solid 6 weekends out of the rears and 3-4 out of the fronts. Im cooking them too. (thats good, you want to be able to get heat into them. if you are not getting 170ish and 5 -10 max degrees less across the tire, you are leaving time on the table.
If you want to see how you are doing as far as pushing your 928 to the edge, look at the Speed Touring car times in World challenge for last season 03, and this season 04 at a track near you. if you are not running at least as fast as they were last season 03, on street tires, then you are not pushing hard enough in a slightly modified 928 set up for racing. If you are running as fast as they are this season, you are running very well. keep in mind, these are professionally set up cars, weighing 200lbs less than most of the race 928s, and have about 275 rear wheel hp running on 225s all the way around! These cars will run about a 2:30 flat at Road america, at least and these are the cars I usually run very close with at tracks on the west coast.
Ive always said, my 928 is a top touring car! (but $100k less money!)
MK
mk
If you want to see how you are doing as far as pushing your 928 to the edge, look at the Speed Touring car times in World challenge for last season 03, and this season 04 at a track near you. if you are not running at least as fast as they were last season 03, on street tires, then you are not pushing hard enough in a slightly modified 928 set up for racing. If you are running as fast as they are this season, you are running very well. keep in mind, these are professionally set up cars, weighing 200lbs less than most of the race 928s, and have about 275 rear wheel hp running on 225s all the way around! These cars will run about a 2:30 flat at Road america, at least and these are the cars I usually run very close with at tracks on the west coast.
Ive always said, my 928 is a top touring car! (but $100k less money!)
MK
mk
Last edited by mark kibort; 06-03-2004 at 07:00 PM.
06-03-2004, 05:43 PM
#33
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as i said, you wont burn the inside edge, due to the high pressures you are running. (see how that works as you will shift wear toward the center?) and , as you "heat cycle them to death" you will make them so hard that they litterally will not wear out. (but will be awefully skatey) you may not notice them being too bad if you only visit tracks like Thunderhill or Road america. However, get on a track like LR or Sears and you will see the difference.
the 928 is an interesting car. we do pretty well with the same set up with two entirely different kinds of tires. Mark Anderson has done ALL three types of tires and the car has behaved quite good. Toyo T1S street tires (treadwear 280), DOT Toyo RA1s, and his goodyear/yoko full slicks. sizes ranging from 275 to 335 too!!
try this on a vet or mustang and you may not be so lucky!
MK
the 928 is an interesting car. we do pretty well with the same set up with two entirely different kinds of tires. Mark Anderson has done ALL three types of tires and the car has behaved quite good. Toyo T1S street tires (treadwear 280), DOT Toyo RA1s, and his goodyear/yoko full slicks. sizes ranging from 275 to 335 too!!
try this on a vet or mustang and you may not be so lucky!
MK
Originally posted by John Veninger
Three years and I haven't corded the inside..yet. Heat cycled them to hell and flat spotted to the cord, but no uneven wear.
So how can one 928 on slicks and one on Dots have the same settings and both are getting full advantage on their setup?
Three years and I haven't corded the inside..yet. Heat cycled them to hell and flat spotted to the cord, but no uneven wear.
So how can one 928 on slicks and one on Dots have the same settings and both are getting full advantage on their setup?
Last edited by mark kibort; 06-03-2004 at 05:58 PM.
06-03-2004, 05:50 PM
#34
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toss it out!! they dont know.
want to know, look at the teams with over 1milliondollars a year spent on set up and racing. (ie speed GT and GRandAm Cup)
the cars are 2700lbs to 3000lbs and they all run in the 28-32psi cold range
these are the top cars.
also, talk to the hoosier rep when you go to the track. they will usually tell you this too. Also , ive done the different pressures. 40psi hot is literally undrivable. as you run the car faster , you will see what im talking about
Ive never seen a problem, on my car or others of an outside edge wearing prematurely. usually the center or inside edge goes first, if you run the tire that long
(quote: "Lower pressure, creating better feel, but lower performance"???? If a tire feels better to me, im usually running faster!
MK
want to know, look at the teams with over 1milliondollars a year spent on set up and racing. (ie speed GT and GRandAm Cup)
the cars are 2700lbs to 3000lbs and they all run in the 28-32psi cold range
these are the top cars.
also, talk to the hoosier rep when you go to the track. they will usually tell you this too. Also , ive done the different pressures. 40psi hot is literally undrivable. as you run the car faster , you will see what im talking about
Ive never seen a problem, on my car or others of an outside edge wearing prematurely. usually the center or inside edge goes first, if you run the tire that long
(quote: "Lower pressure, creating better feel, but lower performance"???? If a tire feels better to me, im usually running faster!
MK
Originally posted by John Veninger
From Hoosier:
Reference the following chart for suggested pressures:
Vehicle size
Recommended Hot Pressure Cold Pressure
1800-2200 lbs.
39-42 30-36
2200-2600 lbs.
40-43 31-37
2600-3000 lbs.
42-46 32-37
over 3000 lbs.
43-48 32-38
Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the Hoosier P-Metric radial tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure may improve the "feel" of the tire however it will also lower the performance and increase the wear on the tire, particularly on the outside tread edge.
The above chart is a general recommendation which is intended for a standard configuration vehicle (i.e. front engine, rear wheel drive).
From Hoosier:
Reference the following chart for suggested pressures:
Vehicle size
Recommended Hot Pressure Cold Pressure
1800-2200 lbs.
39-42 30-36
2200-2600 lbs.
40-43 31-37
2600-3000 lbs.
42-46 32-37
over 3000 lbs.
43-48 32-38
Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the Hoosier P-Metric radial tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure may improve the "feel" of the tire however it will also lower the performance and increase the wear on the tire, particularly on the outside tread edge.
The above chart is a general recommendation which is intended for a standard configuration vehicle (i.e. front engine, rear wheel drive).
06-03-2004, 07:28 PM
#35
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MK,
Datapoint: I run my Hooiser 335/30s from 36 cold, and add/decrease as necessary to get 42 hot. I get even wear with -2 camber on all four corners.
I guess by your statement that "40psi hot is literally undrivable" means that I can expect to take significant time off my 1:01 Lime Rock times if I lower pressure...
Perhaps spring rates needed to be taken into account here? Or maybe the west coast tracks are really different from the east coast tracks?
Hard to understand how Hoosier would provide information that is contrary to what their reps. say at the track....
Datapoint: I run my Hooiser 335/30s from 36 cold, and add/decrease as necessary to get 42 hot. I get even wear with -2 camber on all four corners.
I guess by your statement that "40psi hot is literally undrivable" means that I can expect to take significant time off my 1:01 Lime Rock times if I lower pressure...
Perhaps spring rates needed to be taken into account here? Or maybe the west coast tracks are really different from the east coast tracks?
Hard to understand how Hoosier would provide information that is contrary to what their reps. say at the track....
06-03-2004, 07:34 PM
#36
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Mark,
Do you ever answer stuff in one post or do you have to do it in two or three?
Why in the world would I be visiting West Coast tracks?
I've been at Lime Rock, which wants you to have lots of grip. Watkins Glen, Pocono, BeaveRun, and Road Atlanta.
If 40psi hot is undrivable, then I must be a better driver than I thought.
Try more front camber 
Do you ever answer stuff in one post or do you have to do it in two or three?
Why in the world would I be visiting West Coast tracks?
I've been at Lime Rock, which wants you to have lots of grip. Watkins Glen, Pocono, BeaveRun, and Road Atlanta.
If 40psi hot is undrivable, then I must be a better driver than I thought.
others of an outside edge wearing prematurely
06-03-2004, 08:46 PM
#37
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John,
I answer posts individually. And i did refer to Lime Rock (LR) and Road America to cover both west and easts cost tracks in my explanation
Second, 1:01 at lime Rock wouldnt have got you in the top 30 of the Speed Touring Cars in this last weekends race. They are running a .5 second slower toyo than a hoosier and running :57-8s. the very top 5 cars are 275hp at the wheels, while most are in the 250ish hp at the wheels, and running 225s all the way around! only 200lbs lighter than us. Now, yes, i think you would run a lot faster if you run the tires as I suggest.
Over the last 4 years Ive consistantly run as fast on my hoosiers as the top times in speed GT on street toyos, or a few seconds faster than the leading Touring cars on street toyos. Anderson was running 1:42 on toyos at laguna, while Im running 1:40s on hoosiers . the winning touring cars are running 1:44s at laguna, on toyos and will probably run 1:40 with the new toyos Dot slicks. (same as my time now)
The touring cars on the DOT toyos, just ran Road Atlanta and the top 5 cars are in the 1:36-7 time. remember, these are cars that I run with on the west coast and usually run the same times and generally can beat.
yes, 40psi hot is a pretty loose tire, if its new, then its bareable, if its used, its next to undrivable. If you tried to run a 57 at Lime rock, you may find out what im talking about. By the way, a few of the top Touring cars are also running cold pressures of about 30psi. Im pretty close with Sofronas, Richmond, and Clay to name a few i rally with on occasion)
because i cut my teath running against these guys in BMW porsche challenge, it forced me to do a lot of things right to figure out how to hang without much more power and a lot heavier. now that im lighter, its paid off in faster times but more critical on things like weight, set up and tire condition. I can still run a decent time on a crappy set of tires, but its usually not fun and the car is not very happy, nor am I!
MK
I answer posts individually. And i did refer to Lime Rock (LR) and Road America to cover both west and easts cost tracks in my explanation
Second, 1:01 at lime Rock wouldnt have got you in the top 30 of the Speed Touring Cars in this last weekends race. They are running a .5 second slower toyo than a hoosier and running :57-8s. the very top 5 cars are 275hp at the wheels, while most are in the 250ish hp at the wheels, and running 225s all the way around! only 200lbs lighter than us. Now, yes, i think you would run a lot faster if you run the tires as I suggest.
Over the last 4 years Ive consistantly run as fast on my hoosiers as the top times in speed GT on street toyos, or a few seconds faster than the leading Touring cars on street toyos. Anderson was running 1:42 on toyos at laguna, while Im running 1:40s on hoosiers . the winning touring cars are running 1:44s at laguna, on toyos and will probably run 1:40 with the new toyos Dot slicks. (same as my time now)
The touring cars on the DOT toyos, just ran Road Atlanta and the top 5 cars are in the 1:36-7 time. remember, these are cars that I run with on the west coast and usually run the same times and generally can beat.
yes, 40psi hot is a pretty loose tire, if its new, then its bareable, if its used, its next to undrivable. If you tried to run a 57 at Lime rock, you may find out what im talking about. By the way, a few of the top Touring cars are also running cold pressures of about 30psi. Im pretty close with Sofronas, Richmond, and Clay to name a few i rally with on occasion)
because i cut my teath running against these guys in BMW porsche challenge, it forced me to do a lot of things right to figure out how to hang without much more power and a lot heavier. now that im lighter, its paid off in faster times but more critical on things like weight, set up and tire condition. I can still run a decent time on a crappy set of tires, but its usually not fun and the car is not very happy, nor am I!
MK
Originally posted by John Veninger
Mark,
Do you ever answer stuff in one post or do you have to do it in two or three?
Why in the world would I be visiting West Coast tracks?
I've been at Lime Rock, which wants you to have lots of grip. Watkins Glen, Pocono, BeaveRun, and Road Atlanta.
If 40psi hot is undrivable, then I must be a better driver than I thought.
Try more front camber
Mark,
Do you ever answer stuff in one post or do you have to do it in two or three?
Why in the world would I be visiting West Coast tracks?
I've been at Lime Rock, which wants you to have lots of grip. Watkins Glen, Pocono, BeaveRun, and Road Atlanta.
If 40psi hot is undrivable, then I must be a better driver than I thought.
Try more front camber
Last edited by mark kibort; 06-03-2004 at 09:07 PM.
06-03-2004, 08:54 PM
#38
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As I mentioned to John, that is expected. even wear is NOT what you actually want, you want a shade of wear starting on the inside 1/3rd. the reason, again, is due to the over pressure so that you are not letting the tire do its job, and this is can be proved by the wear pattern. post a JPEG of a close up of your inner and outer 1/3 of tread and Ill post mine. bet you can still see some of the Hoosier hashing on the inside edge, as well as the little rubber casting nipples on the outside. you want that wear arrow to be just clipped at the top. Go look at the wear arrow, I bet you havent even got close to it!!
and yes, as I mentioned to John, a 1:01 at limerock wouldnt get you in the top 30 , yes, top 30! of the touring race last weekend. (:57 to :58 was the top 10) they are on .5second slower toyos and 225s all the way around! so YES, change the tire pressures and you will be amazed at the improvement. you wont be the first racer where this advice has paid off. dont reinvent the wheel. try it out. what do you have to loose, except time!!
Dont try and figure out why the hoosier folks say what they say. (actually its print, as if you talk to the hoosier rep, a good one, he will concure with my suggestion. )
Just helped scot with this same situation a couple of races ago. stopped a nasty push and a loose rear end! 42psi is very very high for pressures on a hoosier
as far as comparisons to east vs west tracks. keep in mind, Lime Rock is a turney track, but still has a 10mph ave speed higher than Sears (Infinion Raceway) out west. So, Sears has got to be the most demanding as it is a very technical track.
MK
and yes, as I mentioned to John, a 1:01 at limerock wouldnt get you in the top 30 , yes, top 30! of the touring race last weekend. (:57 to :58 was the top 10) they are on .5second slower toyos and 225s all the way around! so YES, change the tire pressures and you will be amazed at the improvement. you wont be the first racer where this advice has paid off. dont reinvent the wheel. try it out. what do you have to loose, except time!!
Dont try and figure out why the hoosier folks say what they say. (actually its print, as if you talk to the hoosier rep, a good one, he will concure with my suggestion. )
Just helped scot with this same situation a couple of races ago. stopped a nasty push and a loose rear end! 42psi is very very high for pressures on a hoosier
as far as comparisons to east vs west tracks. keep in mind, Lime Rock is a turney track, but still has a 10mph ave speed higher than Sears (Infinion Raceway) out west. So, Sears has got to be the most demanding as it is a very technical track.
MK
Originally posted by Stan.Shaw@Excell.Net
MK,
Datapoint: I run my Hooiser 335/30s from 36 cold, and add/decrease as necessary to get 42 hot. I get even wear with -2 camber on all four corners.
I guess by your statement that "40psi hot is literally undrivable" means that I can expect to take significant time off my 1:01 Lime Rock times if I lower pressure...
Perhaps spring rates needed to be taken into account here? Or maybe the west coast tracks are really different from the east coast tracks?
Hard to understand how Hoosier would provide information that is contrary to what their reps. say at the track....
MK,
Datapoint: I run my Hooiser 335/30s from 36 cold, and add/decrease as necessary to get 42 hot. I get even wear with -2 camber on all four corners.
I guess by your statement that "40psi hot is literally undrivable" means that I can expect to take significant time off my 1:01 Lime Rock times if I lower pressure...
Perhaps spring rates needed to be taken into account here? Or maybe the west coast tracks are really different from the east coast tracks?
Hard to understand how Hoosier would provide information that is contrary to what their reps. say at the track....
Last edited by mark kibort; 06-03-2004 at 09:16 PM.
06-03-2004, 09:15 PM
#39
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Originally posted by shaaark89
cameron,
not necessarily abnormal, and definitely more related to suspension than tires. softer springs and less sway bar will tend to make this more apt to occur.\
even big time springs and heavy swaybars can allow it:
cameron,
not necessarily abnormal, and definitely more related to suspension than tires. softer springs and less sway bar will tend to make this more apt to occur.\
even big time springs and heavy swaybars can allow it:
06-03-2004, 10:46 PM
#40
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bill,
in effect you are right, a heavier sway bar will transfer force to the outside wheel. however, it will also reduce body roll which will reduce lift on the inside wheel. in combination with a heavier spring and appropraite shock, one should be able to eliminate lift of the inside tire.
one must consider the entire suspension including the rear when contemplating the effects it may have, so it gets more complicated in real life.
in effect you are right, a heavier sway bar will transfer force to the outside wheel. however, it will also reduce body roll which will reduce lift on the inside wheel. in combination with a heavier spring and appropraite shock, one should be able to eliminate lift of the inside tire.
one must consider the entire suspension including the rear when contemplating the effects it may have, so it gets more complicated in real life.
06-04-2004, 11:30 AM
#42
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If you tried to run a 57 at Lime rock, you may find out what im talking about.
I just looked at the LRP results. I wouldof been in 1st or 2nd with a 57!
http://www.world-challenge.com/2004/...c-results.html
My best 1:01.4 last year would put me 6th from the rear of people that ran.
06-04-2004, 03:31 PM
#43
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Yes, you want to have a goal with our cars to be about as fast as the top Touring cars. 57 would have been in front, and there was a bunch of 58s. And yes, 1:01.4, is not a slow time by any streatch, but you would have been in the 30th place range among the touring cars in qualifying.
http://www.world-challenge.com/2004/...p/tc-qual.html
Now, Limerock is kind of a unique track, where the touring and GT cars are probably the closest in time of any of the tracks they visit. thats probably due to the fact that the under a minute lap time makes a one second difference more like 2 seconds on other tracks . The touring cars are set up extremely well and their lighter weight pays big dividends there. But, my point was to make you realize that the potential of a 5 liter 928 at 2700 to 2800lbs is in the range of the very fastest touring cars, whereever they go! At sears and Limerock, I would imagine that they will be a second faster than what i could do, but at laguna the times should be the same. (we will see as the season progresses and I will be at both of these tracks with Speed World Challenge as will mark anderson) . based on folks in GT in the back that ran 1:00, where im usually 1 second faster than them i would predict at least a 59 at limerock for the ole Holbert car.
Also, getting back to pushing your car faster and checking out your tire wear patterns and temps, take a look at these pics as we have already been down this path before. Dean Krenz, running about 3 seconds slower than me at laguna, was running 40psi as well. he threw the tires away, (and I picked them up out of the trash) and he bought new ones. After a discussion with him he agreed to try lowering pressures to 32psi cold. This gave him a better feel and some faster times. His old tires are like brand new, but he didnt want to take them back to Canada.
take a look at his wear pattern at 40psi hot vs mine.
take a look at your own tires and let me know what you see. you probably are leaving at least a second on the table at these pressures!
Mk
http://www.world-challenge.com/2004/...p/tc-qual.html
Now, Limerock is kind of a unique track, where the touring and GT cars are probably the closest in time of any of the tracks they visit. thats probably due to the fact that the under a minute lap time makes a one second difference more like 2 seconds on other tracks . The touring cars are set up extremely well and their lighter weight pays big dividends there. But, my point was to make you realize that the potential of a 5 liter 928 at 2700 to 2800lbs is in the range of the very fastest touring cars, whereever they go! At sears and Limerock, I would imagine that they will be a second faster than what i could do, but at laguna the times should be the same. (we will see as the season progresses and I will be at both of these tracks with Speed World Challenge as will mark anderson) . based on folks in GT in the back that ran 1:00, where im usually 1 second faster than them i would predict at least a 59 at limerock for the ole Holbert car.
Also, getting back to pushing your car faster and checking out your tire wear patterns and temps, take a look at these pics as we have already been down this path before. Dean Krenz, running about 3 seconds slower than me at laguna, was running 40psi as well. he threw the tires away, (and I picked them up out of the trash) and he bought new ones. After a discussion with him he agreed to try lowering pressures to 32psi cold. This gave him a better feel and some faster times. His old tires are like brand new, but he didnt want to take them back to Canada.
take a look at his wear pattern at 40psi hot vs mine.
take a look at your own tires and let me know what you see. you probably are leaving at least a second on the table at these pressures!
Mk
Originally posted by John Veninger
I try all the time, but never get there.
I just looked at the LRP results. I wouldof been in 1st or 2nd with a 57!
http://www.world-challenge.com/2004/...c-results.html
My best 1:01.4 last year would put me 6th from the rear of people that ran.
I try all the time, but never get there.
I just looked at the LRP results. I wouldof been in 1st or 2nd with a 57!
http://www.world-challenge.com/2004/...c-results.html
My best 1:01.4 last year would put me 6th from the rear of people that ran.
Last edited by mark kibort; 06-04-2004 at 03:54 PM.
06-04-2004, 03:37 PM
#44
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Here is my tire ran at 28-29 cold. notice the wear pattern, all the way to the outside edge of the inside edge of the tire. also notice that i also get wear all the way to the outside edge of the outside of the tire. since there is also even wear across it, im not too under inflated and my lap times and tire temps are where they should be 175 170 165 degreesF after a cool down lap is some good temp. if you are getting temp in the tires, and the temps are progressive across, they are working for you.
pay particular attention to this next time you race and report back to us Stan and John. you are probably going to be pleasantly surprised by lowering your pressures about 10psi!!!! (ie down to 30psi, and possibly 28psi cold)
my tire show here is after 3 race weekends. Deans is also after 3 race weekends. if you can see, his tire is almost brand new. (looks like what my tires look like after one race) you drop your times by 3 second a lap, your going to wear your tires out faster. You can do this by making more efficient use of the tire by finding the right pressure. With over 100races running hoosiers and certainly the some of fastest times of any production based car of any year, i think my recommendation of 30-32psi cold to start is a good one. If you disagree, post a time faster than a Speed world challenge touring car on DOT slicks at a track near you, in either a part euro 5 liter or S4 running between 285 to 320rwhp and 2700 to 2800lbs dry. also show us the pictures of your wear patterns!
Keep pushing the 928. we will get on the map yet!!!
MK
pay particular attention to this next time you race and report back to us Stan and John. you are probably going to be pleasantly surprised by lowering your pressures about 10psi!!!! (ie down to 30psi, and possibly 28psi cold)
my tire show here is after 3 race weekends. Deans is also after 3 race weekends. if you can see, his tire is almost brand new. (looks like what my tires look like after one race) you drop your times by 3 second a lap, your going to wear your tires out faster. You can do this by making more efficient use of the tire by finding the right pressure. With over 100races running hoosiers and certainly the some of fastest times of any production based car of any year, i think my recommendation of 30-32psi cold to start is a good one. If you disagree, post a time faster than a Speed world challenge touring car on DOT slicks at a track near you, in either a part euro 5 liter or S4 running between 285 to 320rwhp and 2700 to 2800lbs dry. also show us the pictures of your wear patterns!
Keep pushing the 928. we will get on the map yet!!!
MK