I have had a circuit guide for a little while, and in it it has various items in it to help tune out some issues with setups.
Given GP Bikes is a Sim, these 'trouble shooting tips' should work here as well to some degree, and will definitely help a newer rider begin a foray into setting up a bike, both on track and in GP Bikes.
So here goes. I will list symptoms that are commonly found in the sim (and on track) and possible fixes for them.
Note: Sometimes there is more than one possible fix, so adjusting one value may not work and fixing one issue may cause another.
I will also hopefully get this a sub-board, and expand this to include terminolgy and such, but for now, this seems to be all that is needed.
Symptom - Forks Top Out
Fork Springs too stiff/too much preload/too little oil. (Too light of an oil can be relevant for real world machines but that is not changeable in GP Bikes)
Symptom - Forks Bottom Out
Fork springs too soft/too little preload/air gap too small/compression damping too soft
Symptom - Front End Judder(Chatter) in turns:
Insufficient Fork Rebound Damping
Symptom - Front End Judder(Chatter) on Brakes:
Too much Fork Compression Damping (Real world bikes would also check wheels and brakes for balances/warping/general condition, but generally not an issue in GPB)
Symptom - Rear Wheel Skips on Brakes:
Insufficient Rear rebound damping/rear ride height too low/Changing down gears to quickly - Especially 4 Strokes - (Can also be caused by a too low Idle, which does not affect GP Bikes)
Symptom - Bike Weaves Under Hard Braking:
Rear Ride height too high/Steering Damper too stiff (Not currently adjustable in GP Bikes, but real world riders may find this useful)/wheels out of line(Again not a thing in GP Bikes, but real world riders may find this useful)/Fork Springs too stiff/front compression damping too hard
Symptom - Bike Wallows or Judders(Chatters) through Turns:
Insufficient Rear Rebound Damping
Symptoms - High Speed straight-line weave:
Rear Spring Rate too soft/rear rebound too soft/steering damper too stiff (Not currently adjustable in GP Bikes, but real world riders may find this useful)/head races too stiff/rear ride height too low
Symptoms - Bike Unstable at Speed, Prone to Tankslappers:
Rear Rebound Damping too soft (Or too stiff, adjust either way to pinpoint), trail too short
Symptoms - Rear Wheel Judders Under Power:
Rear Compression Damping too Stiff/Rear Spring Rate too high.
Note: I did not make these tips, they come from professional racers, so before you call me out on them not being right, it ain't me who wrote them