What tire pressure to run?
08-09-2023, 05:18 PM
#21
Le Mans Master
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Has anyone else used white shoe polish to make a few lines across the tire tread, and then drive at different pressures to read how the lines scrub off for best contact width, starting with high pressure and lowering it in testing for best traction, and further for best comfort, without losing full tread width scrub?
I thought about driving across a strip of carbon paper, but all of the people at Staples gave me the deer in the headlights look. I wasn't going to ask them if they had typewriters.
08-09-2023, 05:42 PM
#23
Melting Slicks
I'll just say WOW.
08-09-2023, 06:36 PM
#25
Race Director
Well, the biggest possible contact patch would be with a flat tire, so I’m not sure what that criteria alone accomplishes. Seems to me that there is a trade off between contact patch, handling, steering response, and rolling resistance. I believe some of those are subjective depending on driving style and personal preference.
08-09-2023, 09:11 PM
#26
Le Mans Master
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Actually low inflation causes the center of the tire to bow upward and only the outer edges contact the pavement and wear per the tire companies. Over inflation causes the tires to wear in the center. Here is what Firestone says https://www.firestonecompleteautocar...wear-patterns/
Of course there are exceptions, like wrinkle wall drag slicks where 10 psi is not unheard of and some other racing applications I guess. But, I always ran tubes in my slicks.
Of course there are exceptions, like wrinkle wall drag slicks where 10 psi is not unheard of and some other racing applications I guess. But, I always ran tubes in my slicks.
08-10-2023, 08:03 AM
#27
Drifting
Thanks, no road racing. We generate a lot of temperature in the tires in a 20 minute race and my tire temps taken hot off the track are always fine. I am running the lowest pressures of our group. One race at Indy in murderous heat and humidity I ran 12 psi in the rears and the tire turned on the rim about an 1 1/2" so I know where to stop. The heat didn't even help me at that pressure. When I ran small bore cars with radials the manufactures wanted us to run 37 psi hot! I tried it and it felt like ice racing....I went back to 22 psi.
Just one of my counter to the grain stupid racing ideas that I research, test and sometimes stick with. Do not attempt on street or track as this was on a closed course with a driver who also lost a right front wheel in a sweeping left turn at 100 mph....... You've been warned
Steve
Just one of my counter to the grain stupid racing ideas that I research, test and sometimes stick with. Do not attempt on street or track as this was on a closed course with a driver who also lost a right front wheel in a sweeping left turn at 100 mph....... You've been warned
Steve
08-10-2023, 12:29 PM
#28
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Racing aside.... HEAT is the main cause for sudden tire failure in radial tires.. Just ask Firestone. Lower pressure = more heat.
08-10-2023, 03:30 PM
#29
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Thanks, no road racing. We generate a lot of temperature in the tires in a 20 minute race and my tire temps taken hot off the track are always fine. I am running the lowest pressures of our group. One race at Indy in murderous heat and humidity I ran 12 psi in the rears and the tire turned on the rim about an 1 1/2" so I know where to stop. The heat didn't even help me at that pressure. When I ran small bore cars with radials the manufactures wanted us to run 37 psi hot! I tried it and it felt like ice racing....I went back to 22 psi.
Just one of my counter to the grain stupid racing ideas that I research, test and sometimes stick with. Do not attempt on street or track as this was on a closed course with a driver who also lost a right front wheel in a sweeping left turn at 100 mph....... You've been warned
Steve
Just one of my counter to the grain stupid racing ideas that I research, test and sometimes stick with. Do not attempt on street or track as this was on a closed course with a driver who also lost a right front wheel in a sweeping left turn at 100 mph....... You've been warned
Steve
Now when I am at the drag strip , I will bring my rear air preasure down.
Your idea is not stupid if it works for you.
Thanks
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