Triumph Scrambler Brake Bulb Size

Triumph Scrambler brake bulb specifications indicate a P21/5W size for this motorcycle model. The replacement chart covers 2006 through 2017 production years with corresponding bulb specifications.

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
2006-2017	1157	P21/5W	Check Price

Bulb Specifications

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

Other Locations

Additional Notes

The Triumph Scrambler uses the P21/5W bulb type across all specified model years from 2006-2017.
The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope, one rated at 21 watts and one at 5 watts.
In brake light applications, the lower 5W filament typically serves as a constant running or position light, while the higher 21W filament activates under braking.
The P21/5W operates on a 12V electrical system, which is standard for motorcycles of this type.
The bulb uses a BAY15d bayonet base, which is an offset twin-pin fitting. The offset pin placement is a deliberate design feature that ensures the bulb can only be inserted in one orientation, preventing incorrect filament assignment.
The P21/5W conforms to ECE (Economic Commission for Europe) standards, indicating it is approved for road use across European and many worldwide markets.
Because the BAY15d base uses offset pins, it is not interchangeable with the similarly sized BAY15s base, which is a single-filament fitting with symmetrically placed pins.