KTM 390 Duke vs RKS RZ125

The KTM 390 Duke (2025) and the RKS RZ125 (2026) are compared with the same Moto Kıyas physics model under identical conditions: flat dry asphalt, no wind, a 75 kg rider and no passenger. The KTM 390 Duke is a naked bike with 399 cc, 44.4 hp and 165 kg; the RKS RZ125 is a sport bike with 125 cc, 14.5 hp and unlisted weight. Power-to-weight with the rider: 184.9 hp/ton versus 63.8 hp/ton. On this measure the KTM 390 Duke is 190% ahead.

In the simulation the KTM 390 Duke covers 0-100 km/h (speedometer) in 5.48 s and the RKS RZ125 in 13.42 s; the KTM 390 Duke is quicker by 7.93 s. In the 100-0 km/h brake test, braking distance without the 0.3 s reaction time is 43.7 m for the KTM 390 Duke (with ABS) and 36.4 m for the RKS RZ125 (with ABS). The RKS RZ125 stops 7.3 m shorter. Calculated top speed: 167 km/h (test measurement) versus 125 km/h (estimated from power and drag).

All values are an estimated simulation, not road-test measurements. Technical data comes from the sources listed below; the model uses model-specific parameters calibrated against published road tests for the KTM 390 Duke and class-average calibration (no accepted model-specific road test) for the RKS RZ125. Open the interactive app (currently in Turkish) to watch the run side by side and change the load.