A2 licence: how to check a motorcycle’s power-to-weight ratio

An A2 motorcycle must meet three conditions: no more than 35 kW, a power-to-weight ratio no higher than 0.2 kW/kg, and the rule concerning the original version. For the ratio, divide approved power in kW by the relevant mass shown in the vehicle data; engine size alone is not enough.

Calculate the ratio

The A2 limit cannot be checked by looking only at the kilowatt figure. Power must not exceed 35 kW and the power-to-weight ratio must not exceed 0.2 kW/kg; in addition, the motorcycle cannot derive from a version with more than twice the permitted maximum power. These are separate checks and all must be satisfied. Use approved technical data and the mass defined for the ratio, not a personal estimate or a marketing figure.

The calculation is power in kW divided by mass in kg. For example, if the relevant documents state 32 kW and a mass of 160 kg, the ratio is 0.20 kW/kg: it reaches, but does not exceed, the limit. At 32 kW and 150 kg, the result would be about 0.213, above the threshold. These examples explain the calculation; they do not certify a particular motorcycle because the legally relevant mass must be the one specified and recorded for that vehicle.

Check the data before riding

Read the registration document and certificate of conformity, checking power, mass, category and configuration. For a restricted motorcycle, confirm that the reduction is approved and recorded and that the original version does not exceed twice the A2 power limit. An undocumented physical modification is not enough. If power is given in horsepower, rough conversions can hide an excess: use the kW figure in the official data or ask the manufacturer.

Road-use eligibility for a motorcycle is separate from the test-vehicle requirements, which may include their own minimum characteristics. Ask the driving school or licensing office to check both cases, especially if the motorcycle is electric, modified or imported. Do not confuse maximum power, power-to-weight ratio, engine capacity and maximum authorised mass; they describe different things. Before buying a motorcycle for A2, have the documents for that exact vehicle checked and keep the seller or manufacturer’s response.

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