Triumph TR6 Tail Light Bulb Size

The Triumph TR6 tail light requires a single 1157 bulb size for proper illumination and function. Available data for the specified vehicle covers the range from 1969 through 1976.

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
1969-1976	1157	P21/5W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157	Check Price
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W	Check Price

Other Locations

Additional Notes

The 1157 is the sole bulb type listed across all tail light positions for the Triumph TR6, covering the 1969-1976 model years.
The 1157 is an ANSI-standardized bulb, meaning its physical and electrical specifications are governed by a recognized North American industry standard shared across the United States and Canada.
The 1157 operates on a dual-filament design, with one filament rated at 21 watts for braking or turn signal functions and a second rated at 5 watts for running light functions, both within a single 12-volt bulb.
The base type of the 1157 is a BAY15d bayonet mount, which features two offset locating pins that prevent incorrect rotational insertion, distinguishing it from single-filament bayonet variants that use a different pin configuration.
Because the BAY15d base is specific to dual-filament applications, single-filament bayonet bulbs with a BA15s or BA15d base are not interchangeable with the 1157, despite sharing a similar physical profile.