Yeah few data points; the F3 data Tristan posted has more, and its not a very busy curve, just a slightly non straight line so even 3 points gives some clue ish.

Android, you should sell those as art; could make a fortune.

Quote from Shotglass :

not exactly useful with just 3 datapoints ... you can plot pretty much any curve through these

The shape of the curve is determined from the physical model.

I would guess that the curve would have to be monotonically decreasing and that its second derivative would be positive over the range. With these constraints you can get a pretty good approximation of the curve with only three points. If we had a theoretical model for the tyre curve then we could do even better.

Quote from Peptis :

I would guess that the curve would have to be monotonically decreasing and that its second derivative would be positive over the range. With these constraints you can get a pretty good approximation of the curve with only three points.

im just trying to say it reminds me of the way physics were taught in my school
when the teacher showed us an experiment hed usually take 2 measurements and conclude from those that the data obviously shows a -insert random function- relation (as it was the advances physics course he openly admitted that he hasnt got enough time to do it properly and the experiments are more about getting an idea of how its done so well have to live with 2 points which any curve could be fitted to)

Quote from Gnomie :

I tried it on South City Chicane Route, and it felt really awesome! Good job! I never tried a road going set before, but it was really fun to just drive around in the sunset, looking at the great work the devs have put down on this track. I really liked the FFB your set gives -- feels just right IMO. I'll use it for some laps like that when I need to relax after a race!

Don't thank me it's Bobs set I only changed it slighty.

If you liked that you might also like to try the track day version I made of it also.

http://www.lfsforum.net/showthread.php?p=628560#post628560

The reason I'm posting them is for Niels and anyone else that might know what a street car of similar specs would feel like at the track to compare. To me they feel pretty good

Maybe the trackday set is what you should get data from next Android as it has closer to RL setup values

Quote from Peptis :

The shape of the curve is determined from the physical model.

I would guess that the curve would have to be monotonically decreasing and that its second derivative would be positive over the range. With these constraints you can get a pretty good approximation of the curve with only three points. If we had a theoretical model for the tyre curve then we could do even better.

And that the curve should converge to some positive value at very high loads, representing the shear strength limit. At very high loads, even higher load should just make the rubber break away from the surface faster instead of adding any lateral force.

mu = a*exp(-load/b)+c <-that should do the trick LOL!

Pretty graphs, AndroidXP. Why not make use of the nice skidpad LFS has to collect data instead?

People probably shouldn't use the term "grip" as a substitute for "friction coefficient." It adds to the confusion for most people because most folks consider grip to be the same thing as force. Racers are in an endless quest to "find more grip." Whether that be through raising the friction coefficient of the tires by changing air pressure or through increasing downforce (reducing friction coefficient), they call that increasing grip since either way you get more force at the tires.

Grip = force in my book, although I don't know if there's an actual SAE definition to the contrary.

Nothing ever struck me as odd about the load sensitivity in LFS, even with all the playing on the skidpad I do. If there was no load sensitivity, most of the typical chassis tuning like ARB changes wouldn't do anything, or perhaps do the opposite of what happens in reality in some cases.

Increasing load sensitivity should generally tend to increase understeer when off throttle, and increase oversteer when on it.

Quote from jtw62074 :

Pretty graphs, AndroidXP. Why not make use of the nice skidpad LFS has to collect data instead?

Actually I was driving on the autocross area doing all kinds of different radius turns at different speeds.

anyone care to explain to me how to read these 2?
http://www.lfsforum.net/attach ... id=44132&d=1197566269
http://www.lfsforum.net/attach ... id=44158&d=1197578267
i just cant figure out anything meaningful from these V shapes

Imagine a line lying on top of the data points, this would be the load sensitivity line in LFS. All the other data points at the bottom are a by-product of me not driving at the lateral grip limit all the time.

To get better data we would need a virtual tyre test rig, where you can set wheel speed, load, camber slip ratio and slip angle of the tyre and extract a RAF out of it.

The only graphs I've seen of load sensitivity had a curve that looks like a this:

I have no idea from memory what the axis were labelled as, or the unit values.

Probably peak force versus load. With no load sensitivity it would be a straight line.

thx android now it makes a whole lot more sense

but if tristans (i refuse to call it a graph but i cant think of anything insulting enough atm) then the data from lfs looks a bit too flat (should be the derivative of tristans if im not mistaken)

And another graph for you. This time it should give a much better representation of what's up with LFS' tyres.

I did three runs in the RB4 on the skid pad, modifying it to weigh 700kg, 1290kg and 1900kg in order to get a broader load range. It also has the benefit of a more carefully chosen setup that doesn't suffer from downforce, ARB and severe tyre heat. Furthermore it uses the combined long+lat grip as a base, instead of just the lateral one in my previous graphs. Enjoy

Wowee!

That's great

What's it mean in the end? :hide:

It appears to just show a linear decline like it shouldn't? (except for the far left obviously?)

I think it shows that load sensitivity is a bit overdone at low loads (i.e. CF tending to infinity), a bit too linear at medium loads, and about right at high loads. But I'm guessing quite a bit

Isn't that about right? no load = no force?

^ I think so, too.

OT: On a side note, I was just messing around with a 10 ton RB4 and I noticed something - LFS even models rim heat

I think you're taking a page out of my book on that one

Quote from AndroidXP :

To get better data we would need a virtual tyre test rig, where you can set wheel speed, load, camber slip ratio and slip angle of the tyre and extract a RAF out of it.

Didn't Scawen say he was going to code a virtual tyre test rig up at some stage if you ask him really nicely