Unless you change a setup on track the default gears are the ones in the drivetrain.ini, if you have optional gears they may show as ratios.rto, or 1st.rto, 2nd.rto etc files and optional final gear ratios in a final.rto file but the default gears are still the ones in the drivetrain.ini.
If you change (and save) the setup on track look in the setup folder for the car you used, then the track you were on and for the .ini file that matches the setup you saved (example: setups\ferrari_312t\riverside\test-gears.ini) in this file I have
[INTERNAL_GEAR_2]
VALUE=5
[INTERNAL_GEAR_3]
VALUE=8
[INTERNAL_GEAR_4]
VALUE=6
[INTERNAL_GEAR_5]
VALUE=9
[INTERNAL_GEAR_6]
VALUE=10
Looking at [INTERNAL_GEAR_2]
VALUE=5
In the data folder I have a file 1st2nd.rto file, if I open that up - the ratio at the top is counted as 0, if I go down to what would be number 5 - this should be the ratio (for 2nd gear) used when the setup is loaded.
Your wing/aero settings can also be found here
[WING_1]
VALUE=3
[WING_2]
VALUE=6 for example