How exactly do I use the skid pad to setup a car? A friend of mine told me to take my car out on a skid pad and set the springs up. How exactly do I use the skid pad to do this? My initial thought is no matter how fast I drive I can eventually get the car fly off the circle. Sorry for the noob question but I really don't have a clue as you can see.
You can use the skidpad to give you an indication of the general balance and grip of a car/setup combination. Go out and drive around the largest radius circle at a constant speed where you're not having to make steering corrections, a little bit under the grip limit of the car. Do this for a few laps then start applying more throttle to approach the grip limit. As you do, one end of the car will tend to slide more than the other. If the front starts sliding then your setup is more towards understeer, if the rear start sliding first then it's oversteer. There are lots of points to keep in mind when diagnosing potential handling problems though. It's possible, for example, to make a car which has a general understeer balance to have oversteer just by using the throttle (power oversteer). The application of too much power overwhelms the balance of the chassis and can hide the real problems.
Basically, you can use the skidpad to test setup changes and get a general feel for how a car handles.
Something else to bear in mind in all this is that the skid pad is perfectly flat with no bumps or camber. This is not how many of the corners are in LFS. So, just because you've got a car handling perfectly on the skid pad you shouldn't assume it'll work on all tracks.
Yet another thing to bear in mind is that because the radius of even the largest circle is pretty small you won't get up much speed in any car. This means that in the cars which produce a lot of downforce (any single seater except the MRT and the GTRs) you won't go quickly enough to get a real indication of how the car balance is with downforce. So, again, it's possible to make a car handle really well with great balance in the mechanical grip then take it to a proper track and find out an imbalance in the aerodynamics makes it totally undriveable.
I've attached a couple of replays of some skidpad runs. The first is a car which is setup to oversteer wildly, the second is one setup to understeer a lot.
I hardly ever use it (I could probably count the number of times on one hand), but I can see why some people would find it useful. I can't really do any testing offline - I need the competition to try and drive quickly, when I'm offline I can't seem to go quickly enough so any changes I made don't apply in online races.