Tyre temperatures

[Tim Ling]

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

 

[Lee Downham]

If you race in changeable conditions, you will see varying track and air temps ...

 

[SimbinRacer]

If you race in changeable conditions, you will see varying track and air temps ...

Ok good point. :cyclops:

 

[Lee Downham]

 

[Eagleone]

Problem is there is no way to tell tire load unless perhaps if one uses that telemetry add-on I've read about. It doesn't take alot of increased pressure on all the constant 27 degrees tracks to acheive proper heat distribution on the tires (8-10 deg higher on inside compared to outside and middle in between). Yet Simbin "offers" 200kPa in time trial for some reason.

I think optimum pressure per tire is defined as a function of base pressure plus a fraction of the relevant corner loading (corner weight plus load transfer weight). Now 200kpa at time attack could mean anything, either that it is not taken into account or that it remains constant just like tire temps. Motec gives a good account of tire temps. I use 7 deg Celsius difference front and 5 C at the rear to tune the tires. Others may do different. Lap times are the criterion for this.

 

[SimbinRacer]

I think optimum pressure per tire is defined as a function of base pressure plus a fraction of the relevant corner loading (corner weight plus load transfer weight). Now 200kpa at time attack could mean anything, either that it is not taken into account or that it remains constant just like tire temps. Motec gives a good account of tire temps. I use 7 deg Celsius difference front and 5 C at the rear to tune the tires. Others may do different. Lap times are the criterion for this.

So the method you are proposing is regulate pressure to acheive the base wished for tire heat distribution and then just trial and error increase pressure and watch the laptimes (assuming they are consistant)? No other tricks/aids? Like watching telemetry or something? Do you see a pattern at where approximatly your pressure tends to be optimal for most tracks assuming 27 degrees asphalt temp?

 

[Eagleone]

So the method you are proposing is regulate pressure to acheive the base wished for tire heat distribution and then just trial and error increase pressure and watch the laptimes (assuming they are consistant)? No other tricks/aids? Like watching telemetry or something? Do you see a pattern at where approximatly your pressure tends to be optimal for most tracks assuming 27 degrees asphalt temp?

I meant:

1. Achieve temp distribution with motec (pressure / camber). This is standard, nothing new here.

2. Without getting to math, find the turn where the tire is most loaded (you can see it in motec tire temps) and optimise the tire for that turn.

I dont worry about asphalt temp as long as I can keep the most loaded tire below overheating.

Tire base pressures and load pressures is a different thing. These come from the tire specs.

 

[Dave Stephenson]

I meant:

1. Achieve temp distribution with motec (pressure / camber). This is standard, nothing new here.

2. Without getting to math, find the turn where the tire is most loaded (you can see it in motec tire temps) and optimise the tire for that turn.

I dont worry about asphalt temp as long as I can keep the most loaded tire below overheating.

Tire base pressures and load pressures is a different thing. These come from the tire specs.

Remember to do that for each side of the car.

You will also need to take note of the length of the race too. in long races the tyre temps tend to steadily rise throughout the stints, as the tyre becomes more worn it will slide slightly more each lap thus generating more heat. As the heat increases so does the pressure which will result eventually in a less than optimal heat spread accross the tyre.

As mentioned above when the In/Mid/Outtemps become inbalanced like this the contact patch of the tyre will be reduced. This in turn will mean less grip, more sliding, and further heating.

In long races you will have to make the call for yourself where in the stint you want the tyres to be optimal. ideally I'd say you would want to spend as little time as possible in the scenario I just described so I aim for optimal at around 75-85% distance in the stint. I feel that this gives me the most even feel accross the stint.

Although the tyres will be under pressure at the start the tyres are fresh and the car is heavy with fuel so you will have enough grip. As the fuel load decreases and the tyres wear they counteract each others -ve and +ve effects which gives you an even playing field. eventually optimal temps will be reached giving a time when they are all balanced to attack.

alternatively start with higher temps and attack early and run shorter stints

 

[SimbinRacer]

Thanks for those reflections. I guess I'll have to read up on Motec, looking after the tires is important to compete with the tougher guys out there. It would be fun to run a long WTCC/STCC race, like 50 laps, sometime. Then these things become really important.

 

[Bjorn de Haas]

so if my outside temp is like 90 degrees and the inside is like 85 degrees thats an average of 87,5 in the middle... but my middle temperature in the pitscreen is showing 80 degrees. do i have to lower the psi then?? or raise it??

 

[Eagleone]

so if my outside temp is like 90 degrees and the inside is like 85 degrees thats an average of 87,5 in the middle... but my middle temperature in the pitscreen is showing 80 degrees. do i have to lower the psi then?? or raise it??

Raise press. Although I think you mixed up the temps. Inner should be higher. I/M/O = 90/87.5/85 :wink2:

 

[Bjorn de Haas]

Raise press. Although I think you mixed up the temps. Inner should be higher. I/M/O = 90/87.5/85 :wink2:

yeah true i was taking a example. but thanks for the info.. tire pressure is a big pain hahha

 

[Lee Downham]

Motec makes my head hurt, and remember that when you go back to the garage, it only takes the most recent temp of the tyres. The temps change a lot as you drive around a track.
I tend to use RTT (real time telemetry) or some other similar tool on a 2nd monitor to see what is happening to my tyres and where.
Then I trade off where I need them to be at their optimal on track (ie where I can gain the most time from having most grip) to adjust things accordingly.

As I think is also said in this thread many times though ... chasing tyre temps will drive you nuts - get it roughly there and then pound out the laps to go faster - driving better and knowing the car and track well will find you more time than a finitely tuned setup IMHO.

Or put another way - give an "alien" a reasonable setup and he will still woop yer butt even if you are running what Motec says is a totally "perfect" setup :wink:

 

[Alexandre Pernet]

What about tyre's pressure and temp ?

Hii, I'm asking about tire pressure and temp.

Indeed, when you choose time attck mode in GTR-evo the temp are fixed at 90°C and the pressures at 200kPa.
Is it the best utilisation window for wtcc tires (or all the other series tire's ??) ?

Because in the Basic setup Guide I read "decreasing tire pressure makes for better grip, but increase tire temps and wear"
So when I want to make a "Hot lap" I have to set my tire pressure's to the minimum ?? I'm not talking about wear and temp but just about the grip, If I set the pressure down I'll have better grip, so there is no "perfect pressure" for the tires ?? Right ??

When I have to make a good time (just one lap) low pressure will be better ? Or is it a little bit more difficult ?

Thanks a lot

 

[Dennis Phelan]

Cars in Time Attack mode are unaffected by tire pressures. Just use what your practice/race car has for pressures when driving in TA mode.

Due to this you will probalby never match you TA laptime in qualifying or race modes. If you do, go back to TA and post a lower time as you have obviously learned something!

 

[Marian Zelenka]

It works weird. I can't get higher temps even when lowering pressure. I tried warm up tires today with left-right steering wheel movement, but my tires got colder and colder. I don't care about these issues in race series anymore and focusing on driving. I just want to learn something and move to other sim.

 

[Dennis Phelan]

Yes, in normal practice and race modes it does seem starnge at times. I agree, don't worry abut the small stuff, just drive!

 

[Jim Cole]

Tire temps in Race are basically just to show you how much work the tires are doing. It is near impossible for instance to keep the rear tire temps up on the mini's, they usually drop down a good bit after leaving the pits and stay down. Rear drive cars on the other hand are more capable of keeping the temps up.

 

[Kennett Ylitalo]

That pressure it has on Time Attack may not be showing correctly. The tire is in default optimal conditions all the time so it has no pressure nor temps as a variable but instead a fixed value.

Just put more toe-in/out if you have temp issues, that'll fix it. I actually like that you can punish your tires a bit more and i think that the rise is realistic enough.. One spin will cook your tires to upper limit or pushing against a horrible understeer does the same. Toe-in/out values are pretty low on default setups, mostly i dial several clicks more at the beginning of the session and then lower it gradually. That way the tires are hotter than usual in the practice/qualy short stints. In race two clicks less to make the tires last little bit longer. And default suspensions are a wee bit on the soft side which decreases tire temps even more. When the setup is on the "hard edge" where the car begings to "hover" acros bumbs there's a lot more vertical slipping that heat the tires more than enough. Mini is the only one that has too cold temps at the rear and some Retros on certain tracks.