How do you find the "right" camber values?

[Celeb]

So, I am pretty ok with building setups, but I never understand how I set my camber to the right value. I know that camber is supposed to give lateral grip up to a certain threshold, but I don't know how to find that threshold. Any tips regarding that?

 

[ouvert]

the usuall easy way to do it fast and generally correct is comparing outer, middle, inner tyre temps after few laps .. inner should be hotter than outer and middle should be inbetween. Inner temp 10-15 degrees hotter than outer.
Assuming your pressure is allright.

If your inner gets too hot you have too much negative camber and you will wear them more and you will notice it when braking and accelerating. If you outer is hotter than inner you have not enough negative camber and you will mostly notice it when cornering.
If you middle temps are higher than inner and outer you have too much pressure, if lower you are underpressured.

Should work for AC too ...

 

[Giovaneveterano]

I keep delta temperature between 5 and 8°C, never more.
High values of camber don't improve grip as much as a proper tyre working does.

 

[Celeb]

Thanks for the answers, that helps a lot. When do you look at your temperatures? After crossing the start/finish line or after a certain corner on tracks?

 

[ouvert]

I do it in MoTec .. in general after few laps at the end of lap

 

[Celeb]

Thanks. Sorry for the dumb querstion, but where do you find that graph or value in MoTec? I only found Tyre temp. so far, but not Inner-middle-outer.

 

[Giovaneveterano]

Thanks for the answers, that helps a lot. When do you look at your temperatures? After crossing the start/finish line or after a certain corner on tracks?

I look at the tyre temperature a couple of times during the lap: some tough sections can change the tyres temperature for a couple of corners, but during the overall lap the temperature should be stable.

 

[Guillaume Francois]

Hi @Celeb, if you are using ACTI and motec, instead of looking tyre temp (btw there is only core temp so it won't help that much) you should look at the camber channel, It should be near 0 when cornering ( highest load, tightest corner), so you will have the best traction at corner exit.

For those who don't use telemetry, after a big corner, stop your car and go to pit, difference between inner and outer should not be more than 8° (around 10° while cornering).

 

[Celeb]

Hey, thanks for the info. I looked into the camber channel a bit, but it seems I put in too much camber because I made it so the "spikes" of camber are around 0. Looking at your data, it seems you disregard those spikes which means that my camber was way too high (which I kinda suspected). At least I am not blind for not finding outer and inner temps

 

[Guillaume Francois]

These spikes happen when you usually hit curbs ^^

 

[Celeb]

Wow, ok... Well I just downloaded Motec yesterday so it's good to know that these are usually curbs and bumps

 

[Mr Deap]

In my opinion, the inner tires always ride on the road regardless how little camber you have. I don't think looking at it can point out how much camber you need.

I tested a bit & using high camber setup give sudden burst of traction when riding the rumble strip.

I think if the outer heat as fast as the middle temp, it mean it stay flat while cornering. On most tracks you don't start to accelerate on the rumble strip which I suppose often the rear tires usually doesn't have that much camber on race cars.

I suppose on most situation the front tires will have a larger disparity of temperature between the outer & middle temp to handle the rumble strip while in the back you focus for acceleration keep keeping both outer & middle temp more likely to be close as long as it doesn't rely to much on the rumble strip.

 

[PhilS13]

@Guillaume Francois You say one thing and then your ACTI graph shows outside front at -3.0 and outside rear at -1.0 while cornering. The blurp to 0° you point to is the car rolling while on the inside curb.

@Mr Deap Tuning camber for optimal rumble strip behavior ? dear god.

Temperatures in AC are not as much affected by camber as real life temps are. Using that to setup camber makes no sense in AC.

So overall... advice given is not helping. I might explain the proper way later

 

[Guillaume Francois]

@PhilS13 It was just an example from Motec to give an idea.
I didn't said, look at this perfect graph and learn from the best.

But whatever, just waiting for your answer to light us all

 

[Mr Deap]

@PhilS13 I have explained just after the picture that I probably have to do some compromise. Depending where I drive on(often on rumble strip or not), I adjust the camber for the condition.

The middle & outer temp being close while corning is currently my reference as optimal grip outside the curb. Depending how long I ride on the curb I increase the camber. When I accelerate just before the apex, the back tires aren't on the rumble strip, I leave it closer to being flat on the road while adding bit more to handle the curb at the end.

 

[Jim Liak]

I adjust the camber and see if it goes faster. If not I go back.

 

[Shadowoff]

Test some higher and lower values and check whether its faster or not If not, go back to pits and try something different. Way more reliable than pure data, as your tire temps on inner/middle/outer can be fine while the current setting doesnt match the track and your driving style. Simply learning by doing

 

[Stereo]

I adjust the camber and see if it goes faster. If not I go back.

This pretty much covers it... corners and straights have different ideal cambers, in corners you want the tires at negative several degrees (usually 3-5 has the most grip, as a rule of thumb higher sidewalls should need more camber), in straights you want the tires as near 0 as possible to reduce rolling friction, you can't have both, the fastest balance depends on the track.

 

[PhilS13]

I won't get into the proof of that but I have spend enough time looking at it to confidently say longitudinal effects of camber are way too small in AC for us to give it any consideration in setup. Running lower camber simply does not give the longitudinal benefits commonly assumed to be there in real life, I'm not getting into whether or not AC is accurate about that, I'm only taking what is given and making the best of it. Same for temperatures, I am not seeing a big enough difference in IMO or core temps with varying camber to justify using that as an input for setup. So overall for AC that means : optimize camber for lateral grip and that's it.

I am absolutely not sharing the full method or the tools I have made to get that answer quickly but here is the rough process.

Each tyre has it's own camber/lateral grip relation defined by parameters in the tyres.ini file (assettocorsa\sdk\dev\v1.5_tyres_ac\). You can find the formula it's public. Typical GT tyre peaks at around -3.3°.

Each tyre also has load sensitivity characteristics in tyres.ini. Once again info is public.

The goal is to determine the state(camber and vertical load) of each tyre WHILE cornering,use the tyres.ini data to calculate each tyres' potential contribution to total lateral forces and then checking what effect increasing/decreasing camber has on total axle lateral grip. You do that, you find optimal camber for a given car state.

I can say the inside tyre is often contributing much more than we would think and because of that, running the OUTSIDE tyre at it's -3.3°(or else) peak often hurts total axle grip as the inside loses a lot by doing that. It obviously depends a lot on suspension geometry and wheel loads so guess what, the optimal moves around as much as the weight of the car moves throughout the corner.

TLDR : It's complicated. To answer the original question : there is no easy magical way to find the threshold. Feel remains a decent way assuming one is consistent enough, changing only one end and trying to detect oversteer/understeer is easier than changing both ends and trying to feel an "overall" improvement.

 

[Matheus Machado]

in straights you want the tires as near 0 as possible to reduce rolling friction

Providing enough traction, wouldn't a smaller contact patch reduce rolling friction? Therefore using more negative camber (or positive as it works the same way) would result in less friction.

I know tire self aligning forces come into play, but my feeling is that it isn't high enough to increase rolling resistance that much. I haven't looked into proper data to affirm this, just throwing a quick thought.