Softail Fat Boy

2017 Harley-Davidson Softail Fat Boy Technical Analysis & Specification Breakdown

Engineered by Harley-Davidson for the custom - cruiser motorcycle segment, the 2017 Harley-Davidson Softail Fat Boy relies on a 1690 cc (103.1 cu in) air-cooled v2, four-stroke powerplant. In factory specification, peak output is rated at 75 HP (54.7 kW) at 5,020 rpm while maximum torque reaches 126 Nm (92.9 lb-ft) at 3,000 rpm, transferring power to the rear wheel through a 6-speed gearbox and belt final drive. With a specific output of 44.4 HP per liter and a 2,020 rpm working window between peak torque (3,000 rpm) and peak power (5,020 rpm), the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.

On the scales, the Softail Fat Boy measures 333 kg (734 lbs) wet (curb), translating to a power-to-weight ratio of 0.23 HP/kg (4.44 kg per horsepower). Rider ergonomics and chassis geometry center around a 670 mm (26.4 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 1,690 mm (66.5 in) wheelbase engineered for planted straight-line stability. The 18.93-liter (5 US gal) fuel tank paired with a rated consumption of 5.6 L/100 km provides an estimated theoretical range of roughly 338 km (210 miles) between fill-ups.

Within MotoLibrary's Harley-Davidson archive, this model family spans 8 indexed model years from 1998 to 2019, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.