Tyre temperatures

Tim Ling

It's a million-to-1 chance, but it just might work
I get the feeling there may not be a precise answer to this, but here goes.

The setup guide recommends tyre temps of 90-110 deg. Should I put air in to increase the temp, or take it out? And how many....whatsits...equal 1psi?

I am trying to understand how setups work, lets just say I'm a little, um, special, and need extra help ;)
 
Nahhh mate ... you are not special ... this to me is the quintessential question.

I too, amongst hoards of others probably, am trying to figure all this out, and all I can tell you is that the entire setup contributes to delivering the correct tire temps, and just adding or taking a bit of wind out of 'em will not make it suddenly work for you ... at least that is what I find.

I also find that when I think I should put air in or take air out of the tyres, it sends the whole setup screwy and starts to handle like a wobbly wheeled supermarket trolley :rolleyes:

I also think the add or remove air question itself is based around a curve ... ie. there is a peak at which the tyre is at its optimum pressure and so temp ... stray too far from this in either direction (too hard or soft) and you are going to see temps going off.

Final finding/thought from me on this ...
I look at the 3 x tyre temps, ie ... inner, middle, outer ... and as per the setup guide inner to outer should be no more than 9ºC or so hotter (if otherwise, start to adjust camber settings?).
Then I look at the middle ... the idea (or so i read) is mid-way between inner and outer temps.
Eg. 87 inner, 79 outer middle should be 83-ish. if its 80, add a bit of wind, if its 87, take a bit out.

Here endeth my assumptions and learnings ... but someone please correct me if/where I am wrong, cos it will help me big time too :thumb:
 
The recommended tyre temp for WTCC is between 85-95 Degrees C but thats for over all temp, and in a sence your tires are made of three sections the Inner the Middle and the Outer.

Normaly you want the Inner about 5-7 degrees hotter than the Outer and the Middle should be an adverage of the two.

Raising or lowering the tyres pressure Highers or lowers the middle temp.
 
* Lower pressure = Higher temperature
* Higher pressure = Lower temperature
* Higher spring rates equates to higher temperatures ( tires get "pushed" to the ground)
* More toe in (a greater - value) in the front tires causes higher temperatures
* More toe out (a greater + value) in the rear tires causes higher temperatures
* The Anti roll bar is also used for equalizing the temperatures across a set of wheels
* Higher tire pressure will get you a more responsive setup, but to much and you'll lose grip - lower pressure works the other way around
* The temperature spread across a tire should be between 5-10 degrees C (use camber to adjust temperature)
* Optimal tire pressure is somewhere around 180 psi
* The tires shouldn't get warmer than 100 c (if you want them to last a race)

* Many books have been written that covers this in great length...
* Many race technicians and race drivers never get to grips (no pun intended) with the physics of tires...
:thumb:
Kind regards,
Karl
 
Wow thanks guys! I appreciate your time and effort. Despite the set up guide, I'm still very confused...oh for the simplicity of Geoff Crammonds original GP :rolleyes: Mind you, I managed somehow in Gran Turismo :twitch:
Expect more questions!
 
* Lower pressure = Higher temperature
* Higher pressure = Lower temperature
* Higher spring rates equates to higher temperatures ( tires get "pushed" to the ground)
* More toe in (a greater - value) in the front tires causes higher temperatures
* More toe out (a greater + value) in the rear tires causes higher temperatures
* The Anti roll bar is also used for equalizing the temperatures across a set of wheels
* Higher tire pressure will get you a more responsive setup, but to much and you'll lose grip - lower pressure works the other way around
* The temperature spread across a tire should be between 5-10 degrees C (use camber to adjust temperature)
* Optimal tire pressure is somewhere around 180 psi
* The tires shouldn't get warmer than 100 c (if you want them to last a race)

* Many books have been written that covers this in great length...
* Many race technicians and race drivers never get to grips (no pun intended) with the physics of tires...
:thumb:
Kind regards,
Karl

This is what I needed as my tires were going below 70 during prequal. I need to soften them then... hmm but this was @ 172psi. I am confused as the optimal pressure is 180 but increasing the pressure results in less heat :S Or am i not driving the car hard enough :S
 
I actualy thought that tire temperature would rise with a higher tire pressure instead of lower tire pressure .

The tire functions as a spring to, so when the pressure is lower the tire will function as softer spring , what means less friction what results in lower temperature. And the opposite, higher pressure , like a stiffer spring, the tire temparature will rise.

and in case of still to low temps you could make sure the car is beeing pressed harder on its tires by increasing spring stifness or increasing slow bump setting. a stiffer rollbar also reaches this goal offcourse. But as said before every setting has effect on a other.

but now i am confused about this pressure, temperature relation,
Will the tire get warmer with higher or lower pressure ,

somebody plz correct my thoughts if i'm wrong. :thumb:


Greetz
Richard
 
  • Andrew Evans

hmmm, looking tyretastic in here, so thought i might jump in with a quick question....

i'm having serious problems with tyre degradation... the last coupla events i've been in they're barely lasting 6 laps or so... now, i can't seem to ease back my driving style (driving every lap like it's qually!) because either i won't be able to gain on the guy in front or won't maintain a gap to guy behind...

so, what sort of setup related things could i do to help alleviate this?
 
hmmm, looking tyretastic in here, so thought i might jump in with a quick question....

i'm having serious problems with tyre degradation... the last coupla events i've been in they're barely lasting 6 laps or so... now, i can't seem to ease back my driving style (driving every lap like it's qually!) because either i won't be able to gain on the guy in front or won't maintain a gap to guy behind...

so, what sort of setup related things could i do to help alleviate this?


i would say , less negative camber to spread the wear over the whole tire. If you do not allready have the temps spread perfecly over the tire . maybe a bit less toe-in to decrease the constant wear of front tires, but this will result in less responsiveness.
lower slowbump will result in less tire wear.
looser rollbar will result in less wear.

hope it helps , i probebly forget a whole lot of things

forget to mention steering lock. you drive aggressive so i presume you have steeringlock setting high. maybe decreasing the lock will help , or decrease the sensitivity of you steering wheel.
 
I found a article with the following onformation : writen by James Andrew

"
Tyres
Think of the tyre pressure as the stiffness of the tyre; lower the tyre pressures and the tyres will flex more and the more the tyre flexes, the more heat is generated in the tyre. Increasing the tyre pressures will make them stiffer and therefore won't build up as much heat.
The pressure at which a tyre provides most grip is known as its 'optimum' pressure, usually the tyre temperatures recorded from a session will indicate whether the tyre is above or below the optimum pressure. If you take the average temperature of the two edges of the tyre and compare it to the temperature of the middle of the tyre and the values are identical, this usually means that the tyre pressure is the optimum. If the middle of the tyre is hotter than the edges, the pressure is above optimum. And, if the temperature of the middle of the tyre is less than the edges, the tyre is below its optimum pressure.
However, pressure is not the only thing that matters about the tyre. The temperature of the tyre is just as important if not more so: a racing slick tyre is designed to adhere to the track surface much better when it is hot, although if the tyre overheats it becomes less efficient and wears out very quickly. The optimum tyre temperature doesn't really have an exact value, but it is a 'window'. This window in which the tyre provides most grip is from around 85-105 degrees but varies a bit between compounds and tyre manufacturers. As a general rule the hard compound tyres work best at a slightly lower temperature window of around 75-95 degrees. In professional motor racing it is common practice to run each tyre at a different pressure in an effort to keep all the tyres within the optimum temperature window. For instance, if your right front tyre is only reaching 75 degrees and your left front is reaching 90 degrees, reducing the pressure of the right front tyre would really help increase its operating temperature and result in an overall improvement in front end grip.
Finally, I just want to say that soft compount tyres aren't always the quickest, even for a hot lap. The tyre temperature is much more crucial than the compound, so always pick the compound that keeps the tyre inside the optimum temperature window.


So i gues i was wrong regarding the tire temps relating the tire pressure .
 
Wow. Reading the above, my brain hurts.

Just for my guide, what sort of difference in old money would correctly set up tyre pressures give, either in time per lap, or laps in tyre life.

Pretty much all I'm doing to the default setup now is setting the steering lock, adjusting the amount of fuel, and maybe twiddling with the gearing, based on the fastest bit and the slowest corner.
 
In my (limited) experience, tyre wear also depends how "on the limit" you are driving, plus amount of fuel and so weight you are chucking about, plus track surface (coarse shellgrip, or smooth less abrasive surface) ... plus wheelspins or locking tyres under braking, overheating 'em ... etc, etc

Smoother steadier driving defo helps preserve them too ... now I just need to learn how to do both smooth and steady and fast at the same time :rolleyes:
 

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