Tyre Temp/Pressure ideals? As well as question about optimum tyre pressures

Jenexs · Mar 27, 2017

Heyo, i've been reading around and sadly it turns out that the AC tyre model uses an optimum tyre pressure for best grip, atleast as far as i've read. Now, my question is, does this still apply with the newer tyre models? AFAIK, it would still make sense to use different tyre pressures for the driving style of the driver, no? Unless the game is set to using a set number and however far you deviate from that number, grip deteriorates, is this correct? If so, why doesn't kunos give us a number in the pits for optimum tyre pressures for specific compounds?

Also, I've read the FAQ and found information on tyre temperatures, but it doesn't seem to have all the tyre types listed, (like street 90's for example), anyone know what the temps for those would be as well?

Thanks.

Berniyh · Mar 27, 2017

Yes, the tyre pressure is important with the v10 tyre model as well.

You can read out the optimum tyre pressure and temperature using the tyre app (hint: green is good, blue too low and red too high ) or similar ones.
On most cars the driving style isn't that important, but there are a couple of cars where it really does matter.

Proody · Mar 27, 2017

I have the TyrePressureEngeneer-App this help me
http://www.assettocorsa.net/forum/i...sure-engineer-also-underteer-oversteer.28841/

mms · Mar 27, 2017

Here's another one:
http://www.racedepartment.com/downloads/protyres.14030/

Aristotelis · Mar 27, 2017

Jenexs said: ↑

Heyo, i've been reading around and sadly it turns out that the AC tyre model uses an optimum tyre pressure for best grip, atleast as far as i've read. Now, my question is, does this still apply with the newer tyre models? AFAIK, it would still make sense to use different tyre pressures for the driving style of the driver, no? Unless the game is set to using a set number and however far you deviate from that number, grip deteriorates, is this correct? If so, why doesn't kunos give us a number in the pits for optimum tyre pressures for specific compounds?
Click to expand...

Sadly?
Obviously this is not your fault, I'm not pointing a finger to you in any case and thank you for coming in the pits to get more knowledge. Nevertheless, this the result of the "damage" that some uninformed and bad intended "websites" and forum "experts" are doing, while trying to get the clicks...
So let me ask you that. You'll certainly have heard in all the real races, either in GT or single seater, or prototype, even F1 categories... Drivers complain about grip. Engineers say they had to compromise on tyre pressures to get heat up and setups to work, tyre manufacturers complaining about drivers and engineers keeping the pressures too low or too high and having excess wear and so on. It turns out that real tyres DO have an optimum tyre pressure for best grip/wear/heat. Guess what? AC simulates this (as well as practically every other sim around).

Now, some "smart guys" thought that by opening AC physics and looking at the tyres.ini files, they found the magic number of the optimum tyre pressure and then do an article on it to show "the truth" and how smart and wise they are and how lame AC is. They found an optimum tyre pressure number and thought "that's it, that is were we have to always stay, AC is scripted". Luckily for us and all the people that try and drive AC in depth, this is only just half the truth. There is an optimum pressure as in any real life tyre, but then there's a ton of compromises you have to do and more often than not, the optimum pressure is not at that "magic number" but rather in a range around it.
Will you go for a slightly less pressure to get the tyres heat up more to the correct temperature? But you're gonna lose some precision in handling and probably gain some traction and/or braking.
Will you go for more pressure to cool tyres a bit and have more precision in handling but probably less grip all around but also higher top speed?

So as you can see, yes it's good to be on the optimum pressure. Should you do it? Not really, it's a compromise and you should work around it, find the optimum range and what suits you and your driving style better.

Also, I've read the FAQ and found information on tyre temperatures, but it doesn't seem to have all the tyre types listed, (like street 90's for example), anyone know what the temps for those would be as well?

Thanks.
Click to expand...

As @Berniyh very well said, tyre app is your friend. Get on your car, open the tyre app, do some laps and watch what happens in the tyre app. Adjust your cold pressures trying to bring your hot pressures close to a green colour. Same for tyre temps. The tyre app is all you need, just do 3-4 laps, look at it, go back to the pits, adjust and repeat.

Finally, keep in mind that street cars start with their tyre cold pressures much higher as designed by the car manufacturer. This happens because in that way, while the car travels on normal streets, the tyres are closer to their optimum pressure and thus give optimum grip for normal street driving. So the FIRST thing you have to do on road cars, is immediately lower your cold pressures.

Hope this helps, have fun.

Berniyh · Mar 27, 2017

@Aristotelis: is the heat-up effect for lower pressures really in place? I tried to play around with that a couple of times but never saw a significant effect.
Most recent experiment yesterday with the 787B where I couldn't get the front tyres to temperature (both medium and hard, for hards even the rears were at the lower green range).
If the effect is present (I guess it is) it must be very subtle or only really visible for some cars? F1 maybe?
I did end up in the 787B with around -0.5 to -1.0 psi (relative to the optimum pressure), but going lower had a significant effect on grip, especially a wild rear and understeery front.

The effect of the pressure on the heat up process was the number one effect I expected when first getting into AC and it's what is stated in the tooltip as well and I was a bit surprised how small it seems to be (or maybe I'm misunderstanding something here).
The same goes for the other thing the tooltip mentions, the top speed. I was able to observe that effect but it was quite small as well (but well it's easier to judge changes in top speed and acceleration).

Aristotelis · Mar 27, 2017

Yes it is in place and yes it is subtle. Also if you think about it, 1psi difference is really low. On top of that, there's the whole dynamic changes you're creating in your driving. For example, if you lower your pressure at front, you get a balance with more oversteer, so you might use less "steer" and put the fronts under less slide stress so indirectly you bringing up less heat!
Also keep in mind that while in street tyres you can go up and down a lot with pressures (and get more significant results), in slick tyres you can't do big differences, I mean when you start with 20psi cold, you can go down to 15psi and that's it... Also the more extreme the slick tyre it is the more "stiff" the profile is. It's not like if you will get amazingly more top speed if you manage to put max pressure. The tyre still keeps a decent footprint.

Everything as in real life, is subtle. That's why it's hard to gain laptime. You need to manage to get many things into the correct ball park to gain a minimum amount of time, tenths of seconds.

Schnipp · Mar 27, 2017

Aristotelis said: ↑

Everything as in real life, is subtle. That's why it's hard to gain laptime. You need to manage to get many things into the correct ball park to gain a minimum amount of time, tenths of seconds.
Click to expand...

Well, I rather run with a setup that fits my driving style even if another setup would give me more grip overall.
I don't think a setup that theoraticly is 0.2s faster around the track on a perfect laps is worth having a car that doesn't handle like I want, which in the end means there will be more mistakes that after all lose you more time, like a tail-happy car that has turn-in oversteer or struggles with traction on exit.

Berniyh · Mar 27, 2017

I love tail-happy cars and some of them (e.g. the 911 3.0 RSR) you can really throw into the corner without losing too much time (or in some cases like hairpins actually gaining time).
Although now with 1180° lock-to-lock it's a bit harder then before, but I've got it worked out mostly now.

ChrisR · Mar 27, 2017

Unless @Aristotelis means something else; as far as i'm concerned there is no "optimal" tyre pressure for any tyre per-say, we know the grip from a tyre comes from the footprint & temperature.. so ambient temps, track temps, running temps, brake temps, etc etc all factor into the setting up of the tyres optimum grip.. what you have to do is get the optimal temperature by manipulating the pressure, for example if its really cold outside you will need a different pressure to get as close to optimum temp in the tyre compared to if the day is really hot.. so there can't be an set optimal pressure for a tyre.

Cambers, Toe and caster can all effect the heating of a tyre as well, the aim is get the optimum temps to be as even as possible across the tyre surface, we have a way to see what our surface temps are doing now so we should be able to drive, see how hot/cold a tyre is, change the pressure to change the temps and fine tune the temps across the tyre with the camber/toe etc. (more on this below)

when i setup a car in real life, its a lot of backwards and forwards, you always end up changing tyre pressures to get a decent temp across the tyre, but then you end up pushing harder meaning that you might heat up the outside of the tyre more so you need to add more camber to compensate for the roll which you are now experiencing from the extra G you are achieving, so change camber and then go back out, see how the tyre surface is coping with the cambers, if they are all similar then excellent but for example if the middle is getting hotter than the outsides its because there is too much pressure, and if it was lower, there isn't enough.. effectively you have to balance everything, but everything you change effects something else.. so it really is hard to get it right and it takes time and lots of laps to get the proper temps into your tyre, and guess what.. when you go on a different day and the weather is different you have to start again.

So.

your ideal is equal temps across the tyre (+/- 5c) at the designated "optimum temp"

middle temp is high = pressure to high
middle temp low = pressure too low
inner temp high = too much camber*
inner temp cold = to little camber *
outer temp hot, middle similar but inner colder = adjust toe
inner temp hot, middle similar but outer cold = adjust toe

*Toe can also effect this temperature reading as well

The main point i'm trying to make is that pressure is manipulated just like camber/toe etc to achieve the optimum "temp" across the tyre, there isn't a optimum pressure, just an optimum temp.

ApexPredator · Mar 27, 2017

Aristotelis said: ↑

Sadly?
Obviously this is not your fault, I'm not pointing a finger to you in any case and thank you for coming in the pits to get more knowledge. Nevertheless, this the result of the "damage" that some uninformed and bad intended "websites" and forum "experts" are doing, while trying to get the clicks...
So let me ask you that. You'll certainly have heard in all the real races, either in GT or single seater, or prototype, even F1 categories... Drivers complain about grip. Engineers say they had to compromise on tyre pressures to get heat up and setups to work, tyre manufacturers complaining about drivers and engineers keeping the pressures too low or too high and having excess wear and so on. It turns out that real tyres DO have an optimum tyre pressure for best grip/wear/heat. Guess what? AC simulates this (as well as practically every other sim around).

Now, some "smart guys" thought that by opening AC physics and looking at the tyres.ini files, they found the magic number of the optimum tyre pressure and then do an article on it to show "the truth" and how smart and wise they are and how lame AC is. They found an optimum tyre pressure number and thought "that's it, that is were we have to always stay, AC is scripted". Luckily for us and all the people that try and drive AC in depth, this is only just half the truth. There is an optimum pressure as in any real life tyre, but then there's a ton of compromises you have to do and more often than not, the optimum pressure is not at that "magic number" but rather in a range around it.
Will you go for a slightly less pressure to get the tyres heat up more to the correct temperature? But you're gonna lose some precision in handling and probably gain some traction and/or braking.
Will you go for more pressure to cool tyres a bit and have more precision in handling but probably less grip all around but also higher top speed?

So as you can see, yes it's good to be on the optimum pressure. Should you do it? Not really, it's a compromise and you should work around it, find the optimum range and what suits you and your driving style better.

As @Berniyh very well said, tyre app is your friend. Get on your car, open the tyre app, do some laps and watch what happens in the tyre app. Adjust your cold pressures trying to bring your hot pressures close to a green colour. Same for tyre temps. The tyre app is all you need, just do 3-4 laps, look at it, go back to the pits, adjust and repeat.

Finally, keep in mind that street cars start with their tyre cold pressures much higher as designed by the car manufacturer. This happens because in that way, while the car travels on normal streets, the tyres are closer to their optimum pressure and thus give optimum grip for normal street driving. So the FIRST thing you have to do on road cars, is immediately lower your cold pressures.

Hope this helps, have fun.
Click to expand...

You're awesome, man. LOL! So much information on every answer.

William Levesque · Mar 27, 2017

IRL the same tyre in the same size might(will) run quite different pressures depending on rim width. Narrower = higher pressures, larger = lower pressures. Even more so if tyre size differs.

Just to make things more complicated

Jenexs · Mar 30, 2017

Aristotelis said: ↑

Sadly?
Obviously this is not your fault, I'm not pointing a finger to you in any case and thank you for coming in the pits to get more knowledge. Nevertheless, this the result of the "damage" that some uninformed and bad intended "websites" and forum "experts" are doing, while trying to get the clicks...
So let me ask you that. You'll certainly have heard in all the real races, either in GT or single seater, or prototype, even F1 categories... Drivers complain about grip. Engineers say they had to compromise on tyre pressures to get heat up and setups to work, tyre manufacturers complaining about drivers and engineers keeping the pressures too low or too high and having excess wear and so on. It turns out that real tyres DO have an optimum tyre pressure for best grip/wear/heat. Guess what? AC simulates this (as well as practically every other sim around).

Now, some "smart guys" thought that by opening AC physics and looking at the tyres.ini files, they found the magic number of the optimum tyre pressure and then do an article on it to show "the truth" and how smart and wise they are and how lame AC is. They found an optimum tyre pressure number and thought "that's it, that is were we have to always stay, AC is scripted". Luckily for us and all the people that try and drive AC in depth, this is only just half the truth. There is an optimum pressure as in any real life tyre, but then there's a ton of compromises you have to do and more often than not, the optimum pressure is not at that "magic number" but rather in a range around it.
Will you go for a slightly less pressure to get the tyres heat up more to the correct temperature? But you're gonna lose some precision in handling and probably gain some traction and/or braking.
Will you go for more pressure to cool tyres a bit and have more precision in handling but probably less grip all around but also higher top speed?

So as you can see, yes it's good to be on the optimum pressure. Should you do it? Not really, it's a compromise and you should work around it, find the optimum range and what suits you and your driving style better.

As @Berniyh very well said, tyre app is your friend. Get on your car, open the tyre app, do some laps and watch what happens in the tyre app. Adjust your cold pressures trying to bring your hot pressures close to a green colour. Same for tyre temps. The tyre app is all you need, just do 3-4 laps, look at it, go back to the pits, adjust and repeat.

Finally, keep in mind that street cars start with their tyre cold pressures much higher as designed by the car manufacturer. This happens because in that way, while the car travels on normal streets, the tyres are closer to their optimum pressure and thus give optimum grip for normal street driving. So the FIRST thing you have to do on road cars, is immediately lower your cold pressures.

Hope this helps, have fun.
Click to expand...

Sorry been extremely busy with life and haven't had time to check the forums! Thankyou this makes much more sense. I am using protyre app for my tire needs (has better information for temps and what not.)

Again, thanks, I haven't read through all the replys yet but this is one that helped clear my confusion.

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Physics Bugs & Issues	Tyres doesn't change in pit	Oct 8, 2023
ACC PS4/PS5/XB1/XBX/S General Discussions	1.7.2 tyre temperature	Aug 23, 2023
ACC User Interface	Tyre Pressure Bars not working correctly for dry tyres after 1.9 patch	Jul 7, 2023
Physics modding - Cars & Tyres	Tyre Physics settings ( PIRELLI 265/645-18 DH, DHB, WH )	Jun 29, 2023
ACC Physics	Wet tyres puncturing a lot? (Ferrari challenge evo)	May 26, 2023
ACC Physics	v1.9 Tyre grip falls off a cliff	May 1, 2023
ACC Physics	Tyre pressure range for GT4 & wets?	Apr 25, 2023
ACC Physics	v1.9 Hot Tyre Temps	Apr 24, 2023
ACC PS4/PS5/XB1/XBX/S General Discussions	tyre pressure	Mar 3, 2023
Physics modding - Cars & Tyres	Tyres physics, need some explanations on FZ's, Dx_REF,LS_EXP's and MULT	Jan 19, 2023
ACC Tools	ACC Simhub does not display tyre inner middle and outer temp	Jan 14, 2023

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Tyre Temp/Pressure ideals? As well as question about optimum tyre pressures

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Berniyh Alien

Proody Racer

mms Alien

Aristotelis Will it drift? Staff Member KS Dev Team

Berniyh Alien

Aristotelis Will it drift? Staff Member KS Dev Team

Schnipp Alien

Berniyh Alien

ChrisR Alien

ApexPredator Gamer

William Levesque Alien

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