Two scooters can publish the same power figure and feel completely different, because what you feel is power relative to weight. Power-to-weight is the single most honest performance number on a spec sheet - and you can compute it yourself from manufacturer figures.
How to compute it
Take maximum power in kilowatts, divide by kerb (or wet) weight in kilograms. The Yamaha NVX 155: 11.3 kW divided by 125 kg is about 0.090 kW/kg - usually written 90 W/kg. The Honda Vario 160: 11.3 kW over 118 kg is about 96 W/kg. Despite equal power, the Vario’s ratio is higher - it should feel slightly keener per kilo hauled.
Verified examples (manufacturer figures, retrieved 23 September 2026)
| Model | Power | Weight | Ratio |
|---|---|---|---|
| Honda Vario 160 | 11.3 kW | 118 kg | about 96 W/kg |
| Yamaha Lexi 155 | 11.3 kW | 118 kg | about 96 W/kg |
| Honda SH160i | 12.4 kW | 134 kg | about 93 W/kg |
| Yamaha NVX 155 | 11.3 kW | 125 kg | about 90 W/kg |
| Yamaha NMAX 155 | 11.3 kW | 131 kg | about 86 W/kg |
| Honda Vario 125 | 8.48 kW | 111 kg | about 76 W/kg |
| Honda SH Mode 125 | 8.2 kW | 116 kg | about 71 W/kg |
| Yamaha FreeGo 125 | 7.0 kW | 100 kg | about 70 W/kg |
| Yamaha Janus 125 | 7.0 kW | 97 kg | about 72 W/kg |
What the ratio does and does not tell you
It predicts acceleration feel, hill ability and how the bike copes with a pillion - the core of our Hanoi hills guide. It does not capture gearing, torque shape or wheel size; a 14.8 Nm SH160i engine at low rpm still out-pulls figures suggest on ramps (see our power and torque explainer). And add a passenger and the ratio drops for the lighter bike faster - 50 kg of load hurts a 96 kg Janus proportionally more than a 131 kg NMAX.
Where to use it
Read ratios alongside our kerb weight table and spec-sheet guide whenever you compare classes. All figures above come from official Honda Vietnam and Yamaha Vietnam pages; where a manufacturer does not publish output, no ratio is computed.