The Triumph Thruxton 1200 high beam and low beam headlight bulbs both utilize a 9003 bulb size. The replacement chart covers vehicle production spanning 2016 to 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 bulb is the sole type specified across all headlight positions on the Triumph Thruxton 1200 for the 2016-2018 model years.
The 9003 is a dual-filament halogen bulb, meaning a single bulb contains two separate filaments: one rated at 60W for high beam operation and one rated at 55W for low beam operation.
Because both the high beam and low beam positions share the same 9003 specification, a single bulb type serves both functions within the same headlight housing.
The 9003 bulb operates on a 12V electrical system and uses a P43t base, which is a bayonet-style fitting with a 43mm flange.
The 9003 designation follows the ANSI standard used in the United States and Canada. It is electrically and physically equivalent to the international H4 designation, though the two part numbers originate from different standardization bodies.
The H4 and 9003 bulbs are generally considered interchangeable in practice due to their shared electrical ratings and base type, though fitment should be confirmed against the housing design of the specific application.