Suzuki Motorcycle GW250 Brake Bulb Size

The Suzuki Motorcycle GW250 brake utilizes a P21/5W bulb size for the lighting components. Data for the specific bulb requirements covers the range from 2013 through 2017.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2017	P21/5W
2015	P21/5W
2013	P21/5W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W

Other Locations

Additional Notes

The P21/5W is the brake bulb type specified for the Suzuki Motorcycle GW250 across the 2013-2017 model years.
The P21/5W is an ECE-standard dual-filament bulb, meaning it contains two separate filaments within a single glass envelope. The higher-output filament operates at 21W for the brake signal, while the secondary filament runs at 5W for the tail light function.
The bulb operates on a 12V electrical system, which is standard for motorcycle applications in this class.
The P21/5W uses a BAY15d bayonet base. The BAY15d designation indicates an offset pin configuration, where the two retaining pins are positioned at different heights on the base. This offset is intentional, as it prevents the bulb from being inserted in the wrong orientation, which would reverse the two filament functions.
The ECE designation indicates the bulb conforms to United Nations Economic Commission for Europe regulations, a standard recognized across European and many worldwide markets.
Because the BAY15d base uses an asymmetric pin layout, a BAY15s single-filament bulb or a BA15d straight-pin dual-filament bulb is not a compatible substitute, as neither shares the same base geometry or filament configuration as the P21/5W.