Let's discuss iRacing

or you do a setup to balance the car and then push the car and magically all the tyres get warm Me saying that tarmac doesn't cool the tires down at all was retarded... It does cool them down, but not as much as the air I have tried to find Aris' explanation and failed, but I will give you a quote from Tune to win by Carroll Smith: "The next factor that influences tire performance is temperature. Any process that involves friction produces heat..." and "...Some of the heat so produced is radiated into the airstream, but some of it is stored in a tire."

 

Do you think I did not make changes to the setup ?...

There are certain cars that even with setup changes are still a challenge to get all tires up to optimum temp.

Your taking Carroll's words a bit out of context. He talks about friction; ergo cornering. So heat is generated during cornering and some is lost through the airstream. That does not mean he is stating the airstream "cools tires down more than the surface contact."

So, yes, some is radiated into the airstream, but it is a very small amount of heat that is radiated. As Stereo stated air/gas is a rather poor conductor of heat. That's why the vast majority of engines are water cooled; air cooling isn't sufficient. And that is why radiators are so large; you need a large amount of air flow over them to be effective.

So if your not inducing the proper amount of friction through slip angle, then your cooling the tires by surface contact with a surface colder than the optimum tire temp.

 

Balanced car has balanced temperatures all around, with no need to be aggressive

EDIT: Here, I found what Aris said

"But the key here is that the ambient temperature acts as a dissipator for tyre heat. If you do excessive tests like setting the air at 10°C and the asphalt at 90° you're not going to get a tyre that is overheating constantly. You'll get a tyre that gets overheated in the surface when touching or slipping and then cooled down very fast by the air."

"Furthermore this silliness of of "testing" at 15°C air and 44°C to 1000°C asphalt must end. This is not scientific, this is not realistic. You have a tyre model with 32x3 (IMO) contact points on the circumference surface and you're spinning it at thousand RPM while driving with whatever driving style everytime and you are expecting one contact point that touches the hot asphalt at a thousand of a minute, to change the whole heating issue for the rest 31 contact points that are touching a cold air... what kind of reasoning is this?!"

 

I realize my mistake, I was talking about the outer tyre not the outside of the tyre. Big difference.

I believe the inner side of the tyre gets hotter than outside not because of "magic" as you put but because most cars have camber, where the outside of the tyre is not touching the ground as much as the inside when the car rests. Resting car or moving forward the weight of the car pushes down on mostly the inside of the tyre, being closest to center of gravity to the car. Wearing the inside of the tyre more due to the forces in play.

 

Here's some feedback from someone who has driven race cars. What he means by 'below the limit' and why it would be harder, I do not know.

 

Oh, ok. Yeah, I misread what you tried to say.

Yeah, I know that cars have camber, but if tarmac cooled the tires down more than air, then the inside of the tire should be cold on straights and the outside that is not touching the ground should be hot

 

Yes exactly! It's quite funny that this debate has moved onto AC forums. On the Iracing forum the debate is like 15 pages long already. I don't know how anyone can look at these thermal videos and conclude that the part of the tire with most weight on the ground is cooling the most. (although to be fair I don't think anyone here is disputing the real world data in favour of Dave Kaemmers (Iracing physics guy) statement that contact with the ground produces the most cooling).

Have a look at 0:03 to 0:11 to see inside heating up, and outside cooling down on the straight:

Well I said 'rolling resistance' which is the exact process you describe, so not wrong then.

 

At 3:35 we can clearly see that parts that were touching ground are cooled off compared to other parts of the tire.

 

I renewed my iRacing subscription only a few months ago and to me it still felt totally wrong.

The suspension and weight transfer is just not right IMO - or that's what it feels like. I've driven a few cars to and over the limit and iRacing doesn't feel anything like it, where as AC offers a more realistic representation. It honestly feels like the rotation point or something like that is not quite right in iRacing - like there is a caravan on the back of each car.

Just my thoughts.

 

Sure, but in any given video, you don't know if the outside's touching the ground or not. If it's touching the ground it cools down quickly regardless which explanation you subscribe to. It's only with high camber where it would be off the ground on straights.

Just watch the first 10 seconds of the above video; the tire starts at a uniform temperature (due to tire blankets) and the parts that touch the ground cool off faster than the sides.

 

Well yes, but the car is stationary, when the car is moving in a straight line, friction in the form of rolling resistance is clearly dominant over heat transfer as can be seen in the video I posted.

 

Because of downforce. So many factors. Same F1 car, change wings, different results.

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I guess we need maths and stuff to prove it either way.

 

I think heat is generated and dissipated simultaneously and instantly. The heat transfer doesn't stop because of the friction. The more heat is generated the more is dissipated to the ground because of the temperature differences (tire vs ground) as long as you are not limited by thermal conductivity.
When the car starts moving the tire will move over the fresh (cold) tarmac constantly, so the tire will be able to dissipate more heat. Although the same rule applies to the air flow over the tire when the car starts moving.

 

It all boils down to whether rolling resistance is greater or less than thermal dissipation to the road at any given moment. Rolling resistance will be governed by things like tire compound, tire pressure, road surface, camber angle, weight of car, and downforce. As we saw in the video I posted above, that particular combination of F1 car with high downforce results in the contact patch with the most weight on it heating up. What other combinations will produce is unknown, but my guess would be similar results. ( I might do some RF2 telemetry analysis later for fun and post back)

 

It doesn't really matter what is the ratio of rolling resistance vs thermal dissipation, the heat will be transferred to the tarmac regardless. The ratio of the two will result in either dropping or rising temperature.
Although I don't think that tarmac ability to take heat was the initial question but whether air or tarmac "takes" more heat from the tires.

 

Well we are saying the same thing. (I wrote an explanation why, but it got boring, so I wont go into it)

 

BTW regarding rF2 telemetry, a quote from ISI forum: "Even in the player tire model, road temperature has no impact on anything in rF2. This is from what I have found driving. Tire temperature itself may have an impact on wear, but (real)road temperatures don't transmit properly to tire yet."
Though I haven't tried testing it myself.

 

ok, no point doing any rf2 telemetry then.

 

why no ? .. you still got suspension, gearbox and brakes, etc to setup ... as tyre temps goes .. you still have temps being influenced by setup and them influencing car behaviour .. fact that road temps don`t translate to tyres is surprising but perhaps less substential than we think ..it doesn`t mean that road temp doens`t affect car at all ..