differential_ratio: 1.80 ratios: [8.0, 5.4, 3.8, 2.6, 1.6, 1.0, 0.65] # 0.65 = extreme overdrive Even with the above, the game’s internal limiter may cap you at 90 km/h (default) or 170 km/h (after removing limiter in options). 4.1 In-game settings Go to Options → Gameplay → Truck speed limiter → UNCHECK . 4.2 Console command (developer mode) Enable developer mode in config.cfg :

Example for Volvo FH16:

ProMods’ Iceland – Ring Road has a 14 km straight with no traffic spawns.

uset g_developer "1" uset g_console "1" Then in-game press ~ and type:

differential_ratio: 3.08 ratios: [12.0, 8.2, 5.6, 3.9, 2.6, 1.8, 1.0] Modified for 400 km/h (ultra-tall overdrive):

torque_curve[]: (400, 0.9) torque_curve[]: (1200, 1.0) torque_curve[]: (4000, 0.95) # sustained torque at high RPM torque_curve[]: (5000, 0.85) rpm_limit: 5500 # critical for top speed A diesel engine would explode above ~2800 RPM in reality, but this is a mod. 3.3 Transmission gear ratios Open /def/vehicle/truck/<truck_model>/transmission/<transmission_name>.sii

/def/vehicle/truck/volvo.fh16/engine/d16k750.sii To reach 400 km/h, you need both high RPM and adequate torque at high RPM.

uset g_speed_limit "400.0" At 400 km/h, default truck physics fail: brakes overheat instantly, steering becomes lethal, and trailers jackknife. 5.1 Braking fix Edit /def/vehicle/physics.sii :