Alright, I know countless posts have been made about tires, specially the TGM files. I have come across an issue that I feel may be the final wall holding back some very good dirt/gravel breakthroughs in rF2. I have been working on converting my own mod from rF1. The car is just over 3,000 pounds (1360.77711kg) the suspension looks to be working great and everything appears as though the car is handling and transferring weight very well and the tire physics feel wonderful at first. After a very short time however no matter what I change in either the TBC or TGM files the tires heat up and become too hot then as normal handling goes away, the issue with this however is the heat is being generated at such a massive scale that the tires are 800F (426.666667) after just 2 or 3 laps. It feels as though the load on the tires because of the weight of the car is causing so much friction while the tires slide that the temperature just instantly climbs hundreds of degrees and at those temps the car become uncontrollable. Has anyone any information on the ability to reduce the amount of heat generated per unit of friction between the racing surface and tires as on dirt you must be able to have wheel spin and the sliding of tires without generating nearly the amount of heat as you would on asphalt.
Have you tried reducing the Roughness of the dirt in the .tdf? Obviously there are ways to reduce the grip dropoff with excessive temperatures, but root cause seems a better option if possible.
Yes, I have tried lowering the roughness and raising it, at one point I tried deleting it and neither of the 3 made much difference.
Ok. Deleting it certainly wouldn't help, because it reverts to default values (I think 0.5, 0.25), but no matter. Just curious, have you tried using 'marbles' to effect dirt-like grip, and then increasing the MarbleEffectOnEffectiveLoad ? I'm not sure how you're doing 'dirt grip' at the moment, and I'm not sure there's enough scope there to reduce the heat effect without taking away too much grip, but might be worth a shot. Other than that, I think probably the following line, but it's global so any tarmac running would be affected too: DampingHeatEnergy=(1.0,0.4,0.8) // (Fraction of ring damping heat into sidewall (should probably be 1.0), fraction of bristle damping heat into carcass, fraction of bristle damping heat into tread) the 2nd and 3rd values should generally add up to 1.0
The marble effect came to mind also, but didn't really work as intended. I am still messing with the DampingHeatEnergy as it appears to help a bit, but I'm trying to get the balance of it just right. I did find a way to get roughness to help with the heat, but in order to negate the friction I have to jack the numbers up to non-ideal values (1.5,1.3) that fixes the heat issue, but causes so much grip the second you turn the wheel the grip flips the car over. In rFactor 1 the dirt feel was produced mostly in the slip angles of the tires in the tbc file, but with how much rF2 relies on the tgm file this has been a real challenge to work on.
There are different things you can try to tweak tire average temperature. I think these are the easiest: ('Realtime' section on your tgm file) .... DampingHeatEnergy=( , , ) >>> reduce to obtain less rolling heat (sidewall ,carcass , tread) ... ExternalGasHeatTransfer=( , , ) >>> increase for more heat loss to air ... GroundContactConductance=( , ) >>> increase heat loss to ground And you can also replace specific heat and conductivity for every material on every node (this change doesn't imply to generate a new lookup table). TreadMaterial=( , , , , , X, X) By increasing specific heat you will reduce heating rate when sliding. However, cooling rate will be also slower. Because of that, after increasing specific heats I recommend to increase refrigeration with ExternalGasHeatTransfer. (or reducing DampingHeatEnergy instead)
Thank you Raintyre, I have been looking at those material codes on the nodes, overall wear and everything is great. Heat generation is the only issue. I've reduced DampingHeatEnergy greatly without enough of an effect. I will try the TreadMaterial changes and report back on the outcome.
I just wanted to point out that the title of the thread should be used as a summary of what the thread is about. Someone having a similar problem will not easily identify this in a search result. In my opinion this is not another great tire conversation. It is a thread of someone who clearly had a temperature problem for dirt tires and asked for help.
>>>>Heat generation is the only issue Yes, it is only for tweaking heating rate. However, if you can't reduce temperatures, perhaps you can change temperature effects on grip instead. For example, if i am not wrong, this parameter sets how tread temperature affects static grip. StaticCurve=( temp1, 1, temp2, 1, temp3 , 1) If you set all grip multipliers to 1, you shouldn't observe grip loss on tire static grip. Unfortunately, I guess your issues come when you are sliding, that is, using sliding grip. If i am not wrong, sliding grip change depending on both temperature and sliding speed. If you remove temperature effects on sliding grip, probably you will obtain a very different grip than the original, which should need to recalibrate. I think you can remove temperature effects setting a 0 on one of the Landel Ferry parameters: WLFParameters=( , , 0, ) After that, sliding grip should depend only on speed. You will be free to re-configure at your taste with other sliding parameters: SlidingAdhesionCurve= SlidingMicroDeformationCurve= SlidingMacroDeformationCurve= Good luck!
I forgot! You can also tweak temperature effects on sliding grip changing the 'Glass transition temperature', which is the first value : WLFParameters=( X, , , ) Changing this value you can make your tires more or less grippy when they go to very high temperatures. i think you should increase it but right now i am not sure.... However, it is possible that your handling problems are also due to the pressure increase. Then i recommend starting with much lower tire pressures.
Thanks Raintyre. It is getting much better, I just have to keep testing and tweaking the numbers a bit. The temperatures a very manageable now, just trying to get the tires to like sliding a bit more while still managing to have control at the same time. The last 2 posts you made had the largest effect on the issue. I'll make some more tweaks and continue to dial this in now that it is definitely moving in the right direction! Thank you for your assistance everyone that offered help!
