Harley-Davidson FXDF Fat Bob headlight bulbs use a 9008 size for both high and low beam functions. The replacement chart covers 2008 to 2017 model 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 Harley-Davidson FXDF Fat Bob uses the 9008 bulb for both high beam and low beam headlight positions across the 2008-2017 model years.
The 9008 is a dual-filament halogen bulb, meaning a single bulb unit contains two separate filaments, one dedicated to high beam output and one to low beam output.
The 9008 operates on a 12-volt electrical system and draws 65 watts on the high beam filament and 55 watts on the low beam filament.
The 9008 uses a P26t base, which is a prefocus-type base designed to position the filaments at a precise focal point relative to the reflector housing.
The 9008 designation follows ANSI standards applicable in the United States and Canada, meaning the bulb conforms to a defined set of performance and dimensional criteria within those markets.
Because the same 9008 bulb serves both the high beam and low beam positions on the FXDF Fat Bob, only one bulb type is required to service the entire headlight assembly.
The 9008 is also commonly cross-referenced as H13, and these designations refer to the same bulb specification, though fitment should be confirmed against the P26t base type before substitution.