The Triumph Thunderbird 1700 uses a 9003 bulb size for both high beam and low beam headlight applications. The replacement chart covers 2010 to 2011 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9003 is the sole bulb type listed across all positions and years in these specifications, appearing in both the high beam and low beam headlight positions for the Triumph Thunderbird 1700 across the 2010-2011 model years.
The 9003 is an ANSI-standardized bulb designation used in the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters recognized across North American markets.
The bulb operates on a 12-volt system and carries a dual-wattage rating of 60W/55W, where the higher wattage corresponds to the high beam filament and the lower wattage to the low beam filament.
Because the 9003 contains two filaments within a single housing, it is capable of serving both high and low beam functions from one unit, which accounts for its use across both headlight positions on the Triumph Thunderbird 1700.
The 9003 uses a P43t base, a bayonet-style mount with a 43mm flange, which physically determines socket compatibility and is a factor in fitment verification.
The 9003 is closely related to the H4 bulb, which shares the same dual-filament halogen construction and P43t base but is an ECE-standard designation used outside North America. The two are often cross-referenced, though regulatory and certification differences exist between them.