2018–2020 Harley-Davidson Softail Milwaukee-Eight 107 (FXBB Street Bob)

A New Era: From Dyna to Softail

The most fundamental change for the 2018 Street Bob was the discontinuation of the Dyna frame, which had been in production since 1991. The previous Dyna Street Bob was beloved for its traditional layout, featuring twin external coil-over shock absorbers and a rubber-mounted engine. This configuration gave the Dyna its characteristic feel but was often criticized for chassis flex under aggressive riding conditions.

In contrast, the new Softail platform introduced a lighter, significantly stiffer frame that concealed a single, adjustable monoshock absorber beneath the seat. This design not only provided a cleaner, “hardtail” appearance but also dramatically improved handling dynamics. The new frame, combined with the solidly mounted Milwaukee-Eight engine, created a more responsive and unified chassis. This shift unified the Dyna and Softail lines, a move that was initially met with skepticism by some brand loyalists but ultimately resulted in a motorcycle that was quantifiably better in terms of performance and ride quality.

Design and Characteristics of the 2018–2020 Harley-Davidson Softail Milwaukee-Eight 107 (FXBB Street Bob)

True to its bobber heritage, the FXBB Street Bob is a study in stripped-down aggression. Its defining visual features include high-rise “mini-ape” handlebars that place the rider in an upright, fists-in-the-wind posture. The fenders are chopped, exposing much of the black-laced steel wheels and chunky tires. A solo seat, low-slung profile, and a blacked-out finish on the powertrain, exhaust, and triple clamps reinforce its no-frills attitude.

One of the most distinctive updates was the new digital instrumentation. Departing from the traditional tank-mounted console, Harley-Davidson integrated a small, 2.14-inch digital screen into the handlebar riser clamp. This minimalist display provided all essential information—speedometer, gear indicator, odometer, fuel level, and range—without cluttering the bike’s clean lines. Other modern touches included a keyless ignition system and a signature LED forward headlamp that enhanced both its style and visibility.

Powertrain and Performance

At the heart of the new Street Bob is the Milwaukee-Eight 107 engine. This 107-cubic-inch (1,746 cc) V-Twin was a major leap forward from the Twin Cam engine it replaced. Featuring four valves per cylinder and a single internal counter-balancer, the Milwaukee-Eight runs smoother, produces less vibration at idle, and offers superior heat management.

The engine is tuned for massive low-end torque, delivering a claimed 110 ft-lb at just 3,000 RPM. This power delivery translates to strong acceleration from a standstill and effortless passing power on the highway. Paired with a six-speed Cruise Drive transmission, the powertrain provides a refined yet visceral riding experience that feels both modern and unmistakably Harley-Davidson. The solid mounting of the engine in the new frame also contributed to the overall stiffness of the chassis, further enhancing its handling capabilities.

Chassis, Suspension, and Handling

The redesigned Softail frame was the cornerstone of the bike’s improved dynamics. It was not only stiffer but also lighter than the outgoing Dyna frame, contributing to a significant reduction in overall weight. Up front, the Street Bob was equipped with a Showa Dual Bending Valve (SDBV) fork, a technology borrowed from performance and touring bikes that provides linear damping characteristics for a more controlled and comfortable ride.

The rear suspension featured a coil-over monoshock with preload adjustability, allowing riders to tune the ride for their weight or for carrying a passenger. The combination of the rigid new frame and upgraded suspension components resulted in a motorcycle with a greater lean angle, more precise steering, and a more planted feel in corners compared to its Dyna-based predecessor.