Frame & Chassis

The FXR frame is all welded steel. Rider describes a backbone of two-inch boxed tubing with big stampings, forming a large box section from the steering head to a triangulated rear section, with round tubing wherever the frame shows (Rider, Sep 2017).

It was designed with finite element analysis, and extra gusseting between the steering head, backbone and downtubes made it stiffer than the FLT frame it came from without adding weight (Rider, Sep 2017). Harley's chief engineer told Cycle World it was five times stiffer than the FX frame (Cycle World, Dec 1981).

Hot Bike calls it the stiffest frame Harley ever produced (Hot Bike, "The Saga of the FXR"). The swingarm pivots from the rear of the transmission (Hot Bike, "The Saga of the FXR").

Harley called it a tri-mount system, adapted from the 1980 FLT. Three maintenance-free elastomer mounts carry the engine and gearbox: one horizontal mount in front of the cases at the bottom of the downtubes, and two vertical mounts at the rear where the swingarm attaches at the transmission pivot (Rider, Sep 2017).

Two adjustable stabilizer links with heim joints, one in front of the engine and one on top, keep the drivetrain aligned while the mounts soak up vibration (Rider, Sep 2017).

The later Dyna uses two rubber mounts instead of three. Wikipedia says this made it quicker to build but gave poorer vibration control, a claim it marks as needing a citation (Wikipedia, "Harley-Davidson Super Glide").

Early FXRs had 6.9 inches of fork travel and 3.5 inches at the rear, with Showa shocks (Cycle World, Dec 1981; Hot Bike, "The Saga of the FXR"). The 1983 FXRT added air assistance and anti-dive: a solenoid tied to the brake light switch locks the fork air system when you brake (Cycle World, Aug 1983).

The 1984 to 1985 FXRS Low Glide had lowered suspension, which cost ground clearance. The FXRS-SP put the taller FXRT-style suspension back (Rider, Sep 2017). 39mm forks arrived for 1988 (Rider, Sep 2017). The 1987 FXLR had 6.0 inches of fork travel (Cycle World, Jan 1987).

The first FXRs had three discs: two 10 inch front discs and an 11.5 inch rear (Cycle World, Dec 1981; Hot Bike, "The Saga of the FXR"). The Low Glide dropped to a single front disc; the FXRS-SP and FXRT kept two (Rider, Sep 2017; Cycle World, Jul 1990). The 1987 FXLR used single 11.3 inch discs front and rear (Cycle World, Jan 1987).

Wheels ranged from laced and cast 19 inch fronts to the FXLR's 21 inch laced front and solid disc rear (Cycle World, Dec 1981; Cycle World, Jan 1987). The CVO FXR4 got floating rotors and dual four-piston calipers (Rider, Sep 2017).