Polaris Trail RMK Brake Bulb Size

The Polaris Trail RMK brake utilizes 1157 and 921 bulb sizes for the lighting components located on the rear of the vehicle. Available data covers the time range from 1997 through 2010.

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
2004-2010	1157
2000-2003	921
1997-1998	921

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921

Other Locations

Additional Notes

The Polaris Trail RMK brake bulb specifications cover model years 1997-2010, with two distinct bulb types used across that span: the 1157 and the 921.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W/5W output, and conforms to the ANSI standard used in the US and Canada.
The 921 is a single-filament wedge-style T15 bulb rated at 12V and 16W, also conforming to the ANSI standard used in the US and Canada.
The Trail RMK used the 921 wedge bulb for brake lighting across model years 1997-2000 and 1998-2003, while the 1157 bayonet bulb was specified for model years 2004-2010.
The BAY15d base of the 1157 features two offset pins that lock the bulb into its socket, a design that physically prevents substitution with the 921 wedge base without a socket adapter.
The dual-filament nature of the 1157 allows it to serve both a low-intensity running function at 5W and a high-intensity brake function at 21W within a single housing, whereas the single-filament 921 operates at a fixed 16W.
Because the 1157 and 921 differ in both base type and filament configuration, the two bulbs are not interchangeable across the model years in which each is specified for the Trail RMK.