Suzuki Motorcycle GSX-S1000 front and rear turn signal bulbs use a P21W size. The replacement chart covers 2016 to 2019 model years with bulb specifications for each production period.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W bulb type is specified for both the front and rear turn signals of the Suzuki Motorcycle GSX-S1000 across the 2016-2019 model years.
P21W is an ECE-standardized bulb type, meaning it conforms to the Economic Commission for Europe regulations governing automotive lighting used in European and worldwide markets.
The P21W operates at 12 volts and 21 watts, which is the standard wattage for single-filament turn signal applications in motorcycle lighting systems.
The bulb uses a BA15s bayonet base, a single-contact fitting where the "s" designation indicates a single pin offset, distinguishing it from the dual-contact BA15d variant.
Because the P21W is a single-filament bulb, it serves a dedicated signalling function and is not designed for combined stop and tail light duties, which require a dual-filament configuration.
The front and rear turn signal positions share the same P21W specification across all listed model years, meaning a single bulb type services all four turn signal positions on the motorcycle.
The BA15s bayonet base is not interchangeable with wedge-base or screw-base bulb types, and substitutions using those base types are not compatible with this application.