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Old 02-28-2019, 08:36 PM
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Default contact patch and traction

I was hoping I could get some guidance.

Im a relatively intelligent person but nothing beats experience. Because of my job I have tech that is hard to get ordinarily. Look beyond my flaws and help me with the underlying question. Dont get hung up on the tech...please.

i run on road asphalt touring car and F1. USGT and touring car. i run a track and set the camber according to tire temperature. What this means is that I use a thermal camera to set each tireís camber to have the highest temperature in the center of the tire to maximize contact patch. i do this for all the tires. I change foams and so on so that the hotspots are distributed as much as possible across each tire. Each tire gets a camber adjustment to do this.

so then I do the same thing but instead of each tire i look to average the temperature left to right and front to rear. My cars are balanced before I do this. If i have an even amount of accel and deceleration and left and right corners i set the camber gain to distribute temperature front tire temperatures to each other and rear tires to each other. You never get the same average temperature comparing front to rear but you can get rr and or even and front to rear close.

i dont lose traction and i can tune traction role out.

What i have found is that (im in florida where its almost always hot). Is that my camber is always way under what everyone else runs. Like 1 degree max on an awesomatix and a tc6.2. Same settings for both. I always finish top 3 in blinky club racing (only been racing a year so not bad).

i tune toe in the front for turn in and the rear for high speed stability. No problems and everything works out when i go from track to track.

I see some people tell people to use camber for more or less traction to handle cornering (sometimes camber gain too).

i change droop and ride height if the car does something that the previous does not resolve because im under the impression (my own inexperience maybe) that i want all the traction i can get by keeping the tires flat in a straight line and in a corner. Is that wrong thinking? i dont have a clear advantage on the track over the other faster guys. My car is as fast as anyone i race against (there are guys that i come across sometimes that are clearly from another planet). But i am learning and i want to beat those guys.

My motor setups are equal or better but the aliens are obviously way more consistent and i understand why (experience).

is there some magic in tires that dont have a maximum contact patch under all conditions?
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Old 02-28-2019, 08:50 PM
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I forgot to mention. One thing I have noticed is that on the average if others are run 32 shore tires I have to run 40ís so i dont have too much traction. If I use the same tires as everyone else the tires squeal and i see little micro tears at the end of a race. im also slower if the tires are too sticky.

If the track is cold I do go down in temp tires but Ive got that figured out. in florida I never need to go below 32 and almost never go to a 32. The other guys are at 28 and im borderline 32,36 but if temp comes up at all i just go right to 40s.
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Old 02-28-2019, 08:53 PM
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Sounds like you have the tires figured out actually. Where do you lose time? Entry, exit, do you carry a ton of corner speed? If your equipment is on par then really it's just the driver and technique. If you are getting even tire temps and consistent good traction, sounds like more wheel time is all you need. Bob Wright of RC Crew Chief could help or maybe have some insight as he would understand your tech analysis with temps. He too has discussed the benefit of less camber but making roll center changes to get camber gain to maximize contact patch.
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Old 02-28-2019, 09:00 PM
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I most certainly lose time from lack of experience. My line choice and mistakes is where i lose time. There are a few guys that are just faster everywhere...like they are running a motor class better than me (17.5/13.5). i will keep practicing and I basically learned tuning from RC3 but never really did a reality check with what I thought I learned from the videos and software.

Thank you for your help though.
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Old 03-01-2019, 01:02 AM
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Originally Posted by Bry195 View Post
I most certainly lose time from lack of experience. My line choice and mistakes is where i lose time. There are a few guys that are just faster everywhere...like they are running a motor class better than me (17.5/13.5). i will keep practicing and I basically learned tuning from RC3 but never really did a reality check with what I thought I learned from the videos and software.

Thank you for your help though.
Ask one of those faster guys to drive your car to see how their times compare with yours and what they think of the setup.
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Old 03-01-2019, 08:42 AM
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You ask a very intelligent question and the question really is do we need maximum tire contact patch on all 4 tires and at all times for the fastest lap time. I wish I knew the answer but i don't...and i would like to know what the experts thinks.
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Old 03-01-2019, 09:35 AM
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I've tried using a small thermocouple to try and measure tire temps across the tread, but it didn't show any differences. I like your idea of using a thermal camera, that probably works great. I'm curious, what camber gives you even temps? As far as contact patch, ideally you do want the greatest patch you can get, so you are doing the right things. Where it gets confusing is when you are tuning the car. Depending on your setup, you may have a car that wants to spin, you can adjust the front or rear camber to balance the car. That is go with less camber in the front to reduce traction in the front. Of course you can also do this with spring rates, sway bars, and roll centers along with toe in or toe out. Ideally I would want to have the maximum tire patch at all 4 corners then use the other parameters to balance the car.
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Old 03-01-2019, 09:59 AM
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Where it gets confusing is when you reduce contact patch in rear by increasing rear camber. With less contact patch in the rear you would expect less traction but instead the opposite happens: you gain more rear traction by increasing rear camber.
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Old 03-01-2019, 10:01 AM
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Originally Posted by johnzhou2476 View Post
Where it gets confusing is when you reduce contact patch in rear by increasing rear camber. With less contact patch in the rear you would expect less traction but instead the opposite happens: you gain more rear traction by increasing rear camber.
I think that actually increases the patch because the car leans into the corner. But you can go too far, say 4 degrees of negative camber, then you would wear out the inside half of the tire. Bry would notice the inside of the tire being hotter than the outside with his thermal camera.

There is one thing though, when you get the perfect camber, the tire is flat on the pavement in a turn with the car leaning into the corner. However, on straights, where the car is not leaning, the inside of the tire is making contact. I used to run autocross with my daily driver full size car. If you adjusted your street car to have the proper negative camber for the autocross, then ran those same settings on the street, you would wear out the inside of your tires because most of the miles you put on your street car are in a straight line.
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Old 03-01-2019, 10:26 AM
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Good point above. Another way to measure contact patch without using the thermal method is to run foam tires (if you can find any) on your touring car. How the tires cone or not cone tells a lot. Can't do that or much much harder with rubber tires.
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Old 03-01-2019, 01:56 PM
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Originally Posted by Bry195 View Post
I forgot to mention. One thing I have noticed is that on the average if others are run 32 shore tires I have to run 40’s so i dont have too much traction. If I use the same tires as everyone else the tires squeal and i see little micro tears at the end of a race. im also slower if the tires are too sticky.

If the track is cold I do go down in temp tires but Ive got that figured out. in florida I never need to go below 32 and almost never go to a 32. The other guys are at 28 and im borderline 32,36 but if temp comes up at all i just go right to 40s.
Sounds to me that you have a pretty good grip on tires so my comment won't likely be much help. The way I set camber is to gauge tire wear, if I see the outside edges rounding off I set more camber. Currently I run 3 degrees and don't see any rounding of the outside edges, tire wear is even and traction is high on our asphalt track. Being in a desert we too have to change to 40s as the track heats up, some guys running MOD are even running 40s and using tire warmers when it's not hot out. Keep in mind that tire sauce and tire brand can play a big factor in how your tires perform, experiment a bit here and see what works best for your track surface and tire brand.

I guess I should mention that when I tell people about how much camber I run they usually look at me like I'm from outer space!

Happy racing!
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Old 03-01-2019, 04:06 PM
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Originally Posted by glennhl View Post
I've tried using a small thermocouple to try and measure tire temps across the tread, but it didn't show any differences. I like your idea of using a thermal camera, that probably works great. I'm curious, what camber gives you even temps? As far as contact patch, ideally you do want the greatest patch you can get, so you are doing the right things. Where it gets confusing is when you are tuning the car. Depending on your setup, you may have a car that wants to spin, you can adjust the front or rear camber to balance the car. That is go with less camber in the front to reduce traction in the front. Of course you can also do this with spring rates, sway bars, and roll centers along with toe in or toe out. Ideally I would want to have the maximum tire patch at all 4 corners then use the other parameters to balance the car.
thanks, a static camber of around 1 degree with a camber gain of about .5-.75 degrees per 5mm.

the handheld infrared sensors work too. Just measure from edge to edge and write down the temps.
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Old 03-01-2019, 04:18 PM
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Originally Posted by OttoKrosse View Post
Sounds to me that you have a pretty good grip on tires so my comment won't likely be much help. The way I set camber is to gauge tire wear, if I see the outside edges rounding off I set more camber. Currently I run 3 degrees and don't see any rounding of the outside edges, tire wear is even and traction is high on our asphalt track. Being in a desert we too have to change to 40s as the track heats up, some guys running MOD are even running 40s and using tire warmers when it's not hot out. Keep in mind that tire sauce and tire brand can play a big factor in how your tires perform, experiment a bit here and see what works best for your track surface and tire brand.

I guess I should mention that when I tell people about how much camber I run they usually look at me like I'm from outer space!

Happy racing!
You blew my mind. I cant even comprehend how that works.

a set of Sorex has a piece of overlap tape or something in the belting. Its about 1/2inch long x width of the tire. It is slightly bulged compared to the rest of the belting in the tire. I see this overlap perfectly even from edge to edge when the tire is worn out. The tire wears even from beginning to end.

I run a very short track with lots of corners. The way I average temperatures means that camber gain is holding the patch flat in corners.

Last edited by Bry195; 03-01-2019 at 08:00 PM.
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Old 03-01-2019, 08:14 PM
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Originally Posted by Bry195 View Post
You blew my mind. I cant even comprehend how that works.


Yeah....I get that a lot....but it does work.
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Old 03-01-2019, 08:37 PM
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Originally Posted by Bry195 View Post

a set of Sorex has a piece of overlap tape or something in the belting. Its about 1/2inch long x width of the tire. It is slightly bulged compared to the rest of the belting in the tire. I see this overlap perfectly even from edge to edge when the tire is worn out. The tire wears even from beginning to end.
I'll just put this out there for thought. By no way am I saying your method is wrong as you have achieved maximum use of the available tire. Consider though that maximum contact patch is most desired during the maximum G loading at mid corner. During any other time the tire will have excessive camber and the wear on the inner portion of the tire will continue. Having totally even wear may only indicate that the outer carcass is wearing excessively during cornering and the inner carcass during acceleration and braking thus leaving some cornering potential on the table. Dialing this effect out with roll center and camber gain seems infinitely complex without F1 level on board telemetry and a chassis dyno for off track measurements. Every racer I've known adjusts roll center and camber gain to achieve a performance output in a certain dimension i.e. weight transfer, entry/mid/exit response, tight/sweeping corners etc.
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