Camber and contact patch

[Raintyre]

Hi, i've been trying to set the camber setting to work right, but I usually find difficulties to get a full contact patch on corners using the realistic camber setting. For example, when i use around -3.5 degrees on Formula 1 tyres, the inside of the exterior tyre gets always hotter than the outside on the corners (not only on straights, which is right). On telemetry traces i checked that inside temperature grows faster than center and outside, which i don't think is right.

Thanks to thermal camera shots we can have more information about real tyre temperatures. Interpretation is not simple task because for each tyre we see a mix of behavior on straights, behavior as exterior tyre and behavior as interior tyre, and we don't know the exact temperature or color ranges.
However, if we take a look at the "most used" exterior tyre (front left for Suzuka and Monza) we can see that outside of the tyre often gains temperature faster than inside, until they get almost the same temperature on the middle of corner. Lesmos corners are a good example.
We can also see how inside gets much hotter on straights. I guess cambers used during 2013 were at least -3.5, probably more. Actually Pirelli had to lower camber recommendations after Silverstone, where some teams probably used -4 or -4.5

https://www.youtube.com/watch?v=FHC_nZzRBdk (reversed)

https://www.youtube.com/watch?v=VNYUkRKslEw




That is the behavior i would like to find. However, in the simulation i always must use less camber to get a similar result. I have made this videos to describe it. I used a popular F1 car, but i changed temperature parameters to make heating visible. I didn't find any mod which is better on this subject.

Camber -3.3 >>> Too much temperature on the inside, good inside heating on straights
https://www.youtube.com/watch?v=uZV2LLUeRCI


Camber -2.5 >>> Still too much temperature on the inside
https://www.youtube.com/watch?v=wcWj9rFHNXo


Camber -0.7 >>> Equal temperatures for inside and outside, too little inside heating on straights
https://www.youtube.com/watch?v=-gGApSJN6XU


We probably need some more average temperature on inside than last example, but -2.5 camber is too much, so let's say the perfect camber angle for good contact patch and right temperature spread is around -1.0 or -1.3 degrees. The problem is this is around 3 or 4 times less than the real angles.

'CamberLatLong' parameter on tbc file sets optimum camber for best grip, and this is what drives us to finally use another camber angle, perhaps realistic. However, i think this parameter should match with tyre temperatures observed, and I would say there is not enough positive camber gain on the corners to compensate the initial garage setting and get a full contact patch on the same angle as defined on 'CamberLatLong'.

So, do you know what suspension design and tyre properties do i need to get more positive camber gain on corners? Is there any F1 mod which is perfect on this?

Thank you!

 

[MerlinC]

You might have to consider toe settings in your equation as well, don't you?



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[David Wright]

I think its most likely that the tyre temperatures ISI uses are the temperatures tyre technicians measure with a probe below the surface of the tyre. The surface temperatures as shown on thermal cameras are much hotter than the core temperature (well over 100 degree C) and vary much more rapidly. In conclusion I don't think you can use the thermal videos as a guide to core temperatures.

Camber gain would require a suspension with a short upper arm and a long lower arm. Current F1 cars do not have this kind of suspension - the length of the upper and lower arms is pretty similar so you will get very little if any camber gain.

Even if you did have a suspension with a lot of camber gain, you would need a huge amount of roll to compensate for 3.5 degrees of initial camber. Modern F1 cars have very little roll.

 

[Raintyre]

Thank you, probably you both are right. However, It seems the main problem is that I missunderstood 'camberlatlong' parameter. I received a quite convincing answer at nogripracing.com rfactor forum.

>>>With the introduction of camber a wheel experiences a lateral force in the direction of the camber angle

I guess the consequence is that camber is not set only for compensating car/tyre roll, but also for taking profit of lateral force it produces by itself. That leads to the use of bigger negative camber angles.

I think physics modding requires knowledge about car dynamics and accurate information about the car specifications and performances. However, i think the most important thing i usually miss is the information about "what does this parameter do?" or "how rFactor handles this parameter?".
That could save us a lot of time, and we could produce much better cars with the same effort (which is already big for an amateur who is not paid for that).

 

[Lazza]

I can't disagree with your argument, but personally I thought the camber was pretty obvious; maybe that's because I had read more about various tyre properties including camber thrust, but when you look at the parameter the ISI comment says "Peak camber angle", then "Lateral gain at peak", so that obviously implies a certain amount of camber gains a certain amount of grip above the standard.

That's all in the tyre file, so that has to mean it's purely the tyre camber rather than related to setup somehow (and if you try assuming the opposite, different cars or even different setups could lead to different optimum setup camber values, so that doesn't work). As a final check you do the same thing you already did in comparing inside and outside temperature rates, but make them even during cornering. Then add the CamberLatLong value (in the setup) and you end up with about the same camber everyone tends to end up using on their setups, which proves the theory.

In case you aren't aware, there are some sites around with fully detailed HDV, TBC, etc etc files (with all possible lines included, with all ISI comments, and many further explanations though you need to be careful because sometimes they've misinterpreted it themselves...), otherwise I always found the ISI NationalStockCar a pretty good reference. In general (in rF1, and rF2) later-released cars are better.