Suzuki Motorcycle LT-F160 QuadRunner Tail Light Bulb Size

The Suzuki Motorcycle LT-F160 QuadRunner tail light utilizes bulb sizes P21/5W and 12821 for the lighting components. Available information covers the specific time period from 1991 through 2004 for the specified vehicle.

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
2003-2004	P21/5W
1991-2001	12821

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12821

Other Locations

Additional Notes

The Suzuki Motorcycle LT-F160 QuadRunner uses two distinct tail light bulb types across its production years: the 12821 and the P21/5W.
The 12821 is a Philips part number designating a miniature wedge bulb in the T10 form factor, fitted with a W2.1x9.5d base and rated at 12V, 5W. It is a single-filament bulb.
The P21/5W follows the ECE standard used in Europe and worldwide markets. It features a BAY15d bayonet base and carries a dual-filament design rated at 12V, with a 21W main filament and a 5W secondary filament.
The dual-filament construction of the P21/5W means it serves two lighting functions from a single bulb, typically combining a brighter stop-light output with a dimmer running-light output.
The LT-F160 QuadRunner (Suzuki Motorcycle) used the 12821 bulb across the 1991-2001 model years, representing the longer-running fitment in the specifications.
The P21/5W fitment applies to the 2003-2004 model years, and its BAY15d bayonet base is mechanically incompatible with the W2.1x9.5d wedge socket used by the 12821, making the two bulb types non-interchangeable.
The wattage difference between the two types is notable: the 12821 is rated at 5W total, while the P21/5W draws up to 21W on its primary filament, reflecting a significant difference in output capacity.