This is what I answered in other tuning related thread.I’m not going too technical with it, I check few things from telemetry, things that I cant directly feel, but they affect my speed, and everything else is “butt feel”.
Quote from myself_________________________________________
I tune mostly by “butt feel” Although I’m still tuning only in FM4 as I don’t have FM5 yet. How ever What I have heard from my friends who play FM5, it’s almost same thing so my reply would pretty close to correct answer.
Personally, I start by setting the alignment to somewhat decent figures, Camber and Caster for starters and return later for toe, Then I think a bit of the track is it bumpy (sebring 1st and last corner)
Is it flat (yas marina) Does it have big elevation changes (alps) Do I ride many kerbs (sebring).
For flat track I set the rideheight low and suspension fairly soft. and bump and rebound stiffness fairly stiff (for bump, this is still fairly low we are talking on 2.5-5.0 bump stiffness) Adjust as long as the suspension telemetry gives me only 1 or two red flashes around a lap, and at other times (cornering, running over a kerb, etc) it reaches to this almost.
If its bumpy track where I ride lots of kerbs, go over bigger bumps, etc. I raise that car bit higher, stiffen the suspension a bit, and soften rebound and bump stiffness.
At the end of the day, I’m aiming to set the car so that what ever I do the chassis would go rather smoothly in all conditions, and suspension would work over all the bumps and humps on the road.
I also bring the ARB’s in this. The lower I’m going the stiffer the ARB has to be so that it wouldn’t let the car bottom out in long high speed sweepers (like in indy GP)
Now I set the aero. The aero doesn’t affect too much on low speeds (less than 100kmh/60MPH) but it affects on straights and highspeed corners, To let my car go as fast as possible, on the straight the aero must be low as possible, but when I get to make trough those sweepers as close to full throttle as I can I must set it higher, Therefore I run the corners and adjust accordingly.
If I have to run higher aero profile it gibes more “weight” to the car, so I might have to check again at the suspension, and stiffen it a bit.
Then all the rest what is left here,
Gears, Usually I tend to run sport or stock gearbox, but if I have race gearbox, I tend to set the gears so that I can do 99% of shifting on straights. Then again, you never should shift in corner or right after that, just because it sends always a little pulse (accelerating or decelerating) trough the driveline, which might unsettle the car.
Tire pressure, unless I have adjusted it by now Set it on 33 PSI on hot tires.
Brakes, so that I front and rear lock up at the same time (friction telemetry).
Differental setting have changed so much berween FM4 and FM5 (according to my understanding) that I won’t tell too much about it without testing.
How ever, lower settings helps the car rotating under acceleration and deceleration. While higher setting tend to keep the car going more to a straight line.
You want to floor the throttle as early as possible, and higer setting wants to lock the wheels together, so there would be less wheelspin. How ever, if it locks up too early it will cause you to understeer off the track, or if you had enough power you just cause both tires to lose grip, and that causes oversteer, or complete spinout.
How ever, in FWD cars, you might want fairly high acceleration differential, just to keep you from spinning one tire on acceleration.