For the most part, I find the physics behind rFactor 2 to be incredibly realistic. Tire physics are exceptional except when it comes to thermal properties. Only a precious few mods are anywhere close to being realistic on temps. Not surprising considering the enormous complexity of the task. Reading over the blog (https://www.studio-397.com/2017/12/6512/) it dawned on me that perhaps some of the Studio 397 folks are still struggling a little to understand the finer points of the science. Maybe this will help. There is a little more going on than simple temperature changes when it comes to storing what may otherwise be considered thermal energy. Compounds of long chain polymers store potential energy both in the form of heat and strain in the form of shape change of longer molecular strands. Think of a ball of lint or a starch that gets "unfolded". That strain can be converted to heat; it enables a lag in thermal changes. It is quantifiable, but rather than dwell on that the point is its a factor that impacts thermal characteristics and was overlooked by most of the tire industry less than a decade ago. Michelin, Bridgestone, Pirelli, and BF Goodrich are all using this factor in their tire development programs, other may be using it as well. The most profound understanding comes with how convection and transfer actually pulls heat out of the tires. Unless the tire is rolling at a velocity of less than about 1/4 meter per second, it won't loose much heat through conductance even if the road was made of silver. Tread materials have a very low transfer coefficient so while a very thin layer surface may cool, it doesn't draw much heat from the carcass. Of course change the pavement to something more conventional like asphalt or concrete and that already very small level of transfer shrinks even further. As speed climbs, transfer rates plummet. Most of the heat shedding comes from convection, but its essential to understand how that works. At lower wind shear velocities there is a boundary layer of air between the tire and airflow. In a simple relationship, the faster the wind shear, the deeper the boundary layer is penetrated. Typically at velocities of about 10 meters/second the boundary layer is about 3-4 mm thick. The thermal transfer effect is the tire heats the boundary layer and the boundary layer passes the heat on to the air. There is a form of turbulance in the boundary layer but it still does a pretty good job of insulating the tire from the level it could dissipate. At 20 meters/second the boundary layer drops to about 1.5-2 mm, and dissipates nearly 5X more heat. At 40 meters/second the boundary layer drops to about 1 mm and won't drop in a linear rate; that's about "terminal velocity" for boundary layer penetration. However the higher velocities do continue increased thermal quenching but not at a linear rate. The higher the airflow velocity, the more friction that heats the local air that's contacting the boundary layer to carry away heat. Velocity will reach a point of entropy where the rushed heating of the air is above that of the tire, but you won't reach that point in anything beyond a land speed record vehicle, as its typically twice the speeds run at the Indy 500. Just some outspoken thoughts from a semi-retired aerospace engineer with bit of motorsports background, but it sure would be nice to nail down this loose end to an otherwise superb race simulator.
Yeah....what HE said..... I ... concur..... Actually this dovetails on a subject I brought up back when the Mclaren competion began. Almost all the setups used minimal air pressure settings, which should provide superior grip. But the tire should deform at low pressures and quickly begin to overheat. I don't think we've seen enough of a penalty via heat build-up to low air pressures in tires.
I’ve just woke up so probably not the best time for me to read this and attempt to reply,are you saying that air cools the tyre greater than contact of the road,I’ve bought this very thing up on iracing and here,and been told that’s false,actually everything I read after that,from manufacture tyre pdfs etc says the opposite,and infact the contact of the road cools the tyres greater
I’ve been doing some setup tuning in Ernest,now I’m not a fast guy or setup wiz,but for me lowest pressures are slower,by quite a margin over a race run. This is in the caterham 7,so I don’t know about other cars.
