Harley-Davidson XL1200L Sportster 1200 Low Tail Light Bulb Size

Harley-Davidson XL1200L Sportster 1200 Low tail light bulb size is 3157. The replacement chart covers vehicle production years spanning 2006 to 2011.

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	US Type	EU Type	Shop
2006-2011	3157	P27/7W	Check Price

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157	Check Price

The Harley-Davidson XL1200L Sportster 1200 Low uses the 3157 bulb for the tail light position across the 2006-2011 model years.
The 3157 is an ANSI-standardized bulb type, meaning its physical and electrical characteristics conform to a defined North American specification recognized in both the United States and Canada.
This bulb follows the T25 wedge form factor, which refers to its tapered, wedge-shaped base that seats directly into a compatible socket without a separate metal base or bayonet pins.
The 3157 operates on a 12-volt electrical system, consistent with the standard automotive and motorcycle DC voltage found in this application.
As a dual-filament bulb, the 3157 contains two separate filaments rated at 27W and 7W, allowing it to serve both a higher-intensity brake light function and a lower-intensity running light function within a single housing.
The wattage difference between the two filaments, 27W for braking and 7W for running, produces a noticeable brightness contrast that is a functional requirement for tail light and stop light distinction.
Because the 3157 is a dual-filament type, substituting it with a single-filament bulb of a similar base style would result in the loss of either the running light or the brake light function.