At a Glance
A heavyweight knockout
Adored since day one, the singular Fat Boy stands out with bright chrome and bold finishes, and now it is better than ever with a big Milwaukee-Eight® 117 Custom V-twin engine.
104 HP
25.9 in.
47 mpg
126 ft-lb
DESIGN
New premium paint options and tank medallion embolden the design that has defined the Fat Boy for generations.
PERFORMANCE
The 2025 Fat Boy is more fun than ever before with a new, high-performance Milwaukee-Eight® 117 Custom engine, a high-flowing, two-into-two exhaust system, and improved suspension.
INNOVATION
Classic form hides a suite of modern tech made to add comfort and convenience, but never take attention away from the ride.
Gallery
Rider Safety Enhancements
Harley-Davidson’s Rider Safety Enhancements is all about giving you that extra peace of mind when things get a little unpredictable. It’s a set of smart tech that steps in during tricky situations, helping the bike handle traction while you’re accelerating, braking, or slowing down. With the Cornering Rider Safety Enhancements, the bike even adjusts for cornering, keeping things smooth and steady without you having to think twice.
ABS is designed to prevent the wheels from locking under braking and helps the rider maintain control when braking in a straight-line, urgent situation.
The TCS is designed to keep the rear wheel from “spinning out” when the motorcycle is accelerating in a straight line and enhances rider confidence.
DSCS is designed to reduce excessive rear-wheel slip and help prevent rear-wheel lock under powertrain-induced deceleration, which typically occurs when the rider makes an abrupt downshift gear change or quickly reduces the throttle while on wet or slippery road surfaces.
TPMS alerts the rider through the information display to low or high tire air pressure. Maintaining proper tire air pressure is important both for vehicle performance and tire life.
C-ABS is a variant of ABS that takes into consideration the lean angle of a two-wheel motorcycle, or the lateral acceleration of a Trike model. The brake pressure required to limit wheel slip when cornering is typically or lower than the pressure required under straight line operation.
C-ELB takes into account the motorcycle lean angle or Trike lateral acceleration. C-ELB will alter the proportioning of brake pressure between the front and rear brakes when braking while cornering in an attempt to improve the ability of the bike to maintain the rider's intended path.
C-TCS is designed to prevent the rear wheel from excessive spinning under acceleration when going straight or cornering.
Technical Specifications
Length
93.1 in.
Width
40 in.
Seat Height, Unladen
25.9 in
Ground Clearance
4.9 in.
Rake
30
Trail
4.1 in.
Wheelbase
65 in.
Tire, Type
Michelin® Scorcher 11, front and rear
Tires, Front Specification
160/60R18,70V,BW
Tires, Rear Specification
240/40R18,79V,BW
Fuel Capacity
5 gal.
Oil Capacity (w/filter)
5 qt.
Weight, In Running Order
694 lb.
Engine
Milwaukee-Eight® 117 Custom
Bore
4.075 in.
Stroke
4.5 in.
Displacement
117 cu in
Compression Ratio
10.3:1
Fuel System+
Electronic Sequential Port Fuel Injection (ESPFI)
Exhaust
2-into-2 staggered; catalyst in muffler
Engine Torque Testing Method
J1349
Engine Torque+
126 ft-lb
Engine Torque (rpm)
3000
Horsepower
104 HP / 77 kW @ 4800 rpm
Lean Angle, Right (deg.)
25.6
Lean Angle, Left (deg.)
25.6
Fuel Economy Testing Method
Estimated City/Hwy
Fuel Economy+
47 mpg
Primary Drive
Chain, 34/46 ratio
Gear Ratios (overall) 1st
9.311
Gear Ratios (overall) 2nd
6.454
Gear Ratios (overall) 3rd
4.793
Gear Ratios (overall) 4th
3.882
Gear Ratios (overall) 5th
3.307
Gear Ratios (overall) 6th
2.79
Front Fork
Dual-bending valve 49 mm telescopic with aluminum fork triple clamps; dual rate spring; "beer can" covers
Rear Shocks
Hidden, free piston, coil-over monoshock; 43mm stroke; hydraulic preload adjustment
Wheels, Front Type+
Machined, Lakester cast aluminum
Wheels, Rear Type+
Machined, Lakester cast aluminum
Brakes, Caliper Type
4-piston fixed front and 2-piston floating rear
Brakes, Rotor Type
Front and rear silver, Split 7-spoke floating rotors
Lights (as per country regulation), Headlamp, Tail/Stop/Front Signal Lights+
Headlamp: All LED, low beam, high beam and signature position lamp; Tail/Stop: Bullet-style, LED stop/tail/turn signals; Front Signal Lights: LED Bullet Turn Signals
Gauges
5-inch analog speedometer with digital gear, odometer, fuel level, ride modes, heated gear, traction control, ABS, TPMS, cruise control, clock, trip, range and tachometer indication