| Specification | Value / Part Number |
|---|---|
| Engine Oil | SAE 20W-50 H-D 360 / SYN3 (4.7 L) |
| Front Tire | 110/90B19 62H (36 psi / 2.5 bar) |
| Rear Tire | 180/70B16 77H (42 psi / 2.9 bar) |
| Battery | H-D Part #66000207 |
| Spark Plug | 6R10 |
| Production Years | 2020–Present |
Engineering Heritage: The Evolution of Performance
The Harley-Davidson Softail Low Rider S (FXLRS) represents a pivotal moment in Milwaukee engineering. While it draws aesthetic inspiration from the 1977 FXS Low Rider, its modern soul is defined by the 2020 transition from the legacy Dyna platform to the high-performance Softail chassis. This engineering shift increased the frame’s stiffness by 34% while significantly reducing weight, creating a cruiser that demands to be ridden like a sport-standard.
Technical Analysis: Chassis and Powertrain
At the heart of the FXLRS is the Milwaukee-Eight powertrain, integrated into the monoshock Softail frame. The inverted 43mm front forks and a steeper 28-degree rake (compared to the standard Low Rider’s 30 degrees) provide the aggressive handling characteristics that define the ‘S’ designation. This geometry, paired with the dual front disc brakes, positions the FXLRS as the premier performance-cruiser in the H-D lineup.
Maintenance Guide & Technical Specifications
Maintaining the integrity of the FXLRS requires adherence to strict fluid and component specifications. The Milwaukee-Eight engine is sensitive to thermal management; therefore, MotoSpecsLab recommends the use of Screamin’ Eagle SYN3 synthetic lubricant, particularly in high-ambient temperature environments.
Lubrication System
The total oil capacity is 4.7 Liters (approx. 5.0 US quarts). Ensure the engine is at operating temperature before checking levels via the dipstick. Using the correct SAE 20W-50 viscosity is critical for maintaining hydraulic lifter pressure and cooling the piston undersides.
Wheels and Tires
The FXLRS utilizes a staggered 19-inch front and 16-inch rear cast aluminum wheel setup. Optimal handling is achieved only when maintaining the precise pressures of 36 psi (Front) and 42 psi (Rear). Under-inflation leads to sluggish turn-in and premature cupping of the 180-series rear tire.
Electrical and Ignition
The ignition system relies on 6R10 spark plugs. These should be inspected for carbon fouling every 5,000 miles. For electrical reliability, the 66000207 battery provides the high cold-cranking amps (CCA) required to turn over the large-displacement V-twin.
Frequently Asked Questions
What is the recommended service interval?
Standard service intervals are every 5,000 miles (8,000 km), with the primary and transmission fluids requiring specific attention alongside the engine oil.
Can I use non-Harley branded oil?
While any high-quality SAE 20W-50 meeting JASO MA2 standards is acceptable, the H-D 360 and SYN3 are formulated specifically for the air/oil-cooled thermal cycles of the Milwaukee-Eight.