Harley-Davidson XL1200R Sportster 1200 Roadster Tail Light Bulb Size

Harley-Davidson XL1200R Sportster 1200 Roadster tail light bulb uses a 3157 size. The replacement chart covers vehicle production years spanning 2004 to 2008.

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
2004-2008	3157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157

Other Locations

Additional Notes

The Harley-Davidson XL1200R Sportster 1200 Roadster uses the 3157 bulb for its tail light across the 2004-2008 model years.
The 3157 is an ANSI-standardized bulb type, meaning its specifications are governed by a formal industry standard applicable in the United States and Canada.
This bulb follows the T25 wedge form factor, which refers to a wedge-base design with a 25mm body width, allowing tool-free insertion and removal from compatible sockets.
The 3157 operates on a 12-volt electrical system, consistent with the standard automotive and motorcycle electrical architecture found in this vehicle.
Its dual-filament construction provides two distinct brightness levels within a single bulb, with the higher-draw filament rated at 27 watts and the lower-draw filament rated at 7 watts, serving separate lighting functions such as running light and brake light from one unit.
Because the 3157 is a dual-filament bulb, substituting it with a single-filament alternative would result in the loss of one of those two lighting functions, making filament count a critical factor in replacement selection.