Softail Fat Boy Lo FLSTFB (2015): "Building on the Fat Boy Legacy," With Custom Black Bullet-Hole Wheels and a Genuine Sub-24.5-Inch Seat
Ultimate Motorcycling's own confirmed 2015 lineup preview describes exactly what separates this bike from the standard Fat Boy: "building on the Fat Boy legacy, the Fat Boy Lo brings a darker, slammed appearance to the world of boulevard cruisers. From front to back, this custom cruiser shows attitude, with custom, black bullet hole wheels, a denim black frame, blacked-out covers and header shields, and satin chrome in all the places chrome would normally be. But it's not just about looks. The narrow-cut seat rides just 24.25-inches off the ground, while the forward foot controls and low, 1.25-inch handlebar create a secure stance."
Power comes from the air-cooled Twin Cam 103B, a 1,690cc V-twin with a 3.87-inch bore and 4.374-inch stroke and a 9.6:1 compression ratio, fed by Electronic Sequential Port Fuel Injection, run through a 6-speed Cruise Drive transmission with belt final drive and a 34/46-ratio chain primary drive. TotalMotorcycle's own confirmed factory spec sheet lists gear ratios starting at 9.311:1 in first gear, matching the fundamental drivetrain shared across Harley's whole 2015 Softail lineup.
That same confirmed spec sheet lists a genuinely aggressive 31.6-degree rake with 5.8 inches of trail on a 64.2-inch wheelbase, a 24.3-inch laden seat height (26.4 inches unladen), and just 4.9 inches of ground clearance — real, measurable confirmation of the "Lo" designation's lower stance versus the standard Fat Boy's 25-inch laden seat height. Riding on the same 140/75R17 front and 200/55R17 rear tire sizing as the standard model, this trim's genuine distinction comes down to blacked-out finish and lowered suspension geometry rather than a different powertrain.
Confirmed fluid capacities list a 5-gallon fuel tank and 3.5 quarts of oil (with filter), with shipped weight at 700 lbs rising to 731 lbs in running order. 2015 US pricing started at $17,499 for Vivid Black — genuinely $200 less than the standard Fat Boy despite the Lo's added blacked-out treatment. This exact FLSTFB configuration ran through 2017 before Harley's 2018 Softail platform redesign discontinued the dedicated "Lo" trim entirely, folding its lower-seat-height concept into the standard FLFB and FLFBS models on the new single-shock chassis.
This factory service manual covers the procedures, torque specs, and diagrams needed to keep a 2015 Softail Fat Boy Lo FLSTFB running the way it was built to.
