The year 2020 marked a turning point for Harley-Davidson motorcycles. The iconic American motorcycle manufacturer introduced its Reflex Defensive Rider System (RDRS) on all Harley-Davidson CVO, Tri Glide, Freewheeler, and Ultra models, as well as the failed LiveWire electric bikes, beginning with the 2021 model year. The high-tech safety system is also optional for Harley Touring bikes. Rather than being a standalone safety feature, Harley-Davidson's RDRS is a collection of intelligent traction, acceleration, cornering, and braking technologies developed to enhance rider safety, handling, and motorcycle control, especially on challenging road conditions or in adverse weather.
Harley-Davidson has since renamed its RDRS system to the lengthier and more confusing RDRS Safety Enhancements, with some bikes getting motorcycle-specific "cornering enhanced" features that function differently than the stability and traction control systems found in four-wheeled automobiles.
All Harley bikes equipped with RDRS have an inertial measurement unit (IMU) to monitor and measure the lean angle (two-wheeled bikes) or lateral acceleration (three-wheeled trikes) when turning or cornering. The system analyzes the speed and size of the front and rear wheels while accounting for the tire contact patches. This enables the RDRS system to optimize its intervention, and it works whether the bike is upright or leaning aggressively into a curve.
The Harley RDRS Safety Enhancements collection starts with Cornering Enhanced Electronic Linked Braking (C-ELB). The system automatically applies the brakes to the front and rear wheels, regardless of whether the rider is using the hand lever or foot pedal to intentionally brake the front or rear wheels, respectively.
Harley claims the C-ELB system enhances braking performance, improves responsiveness, and optimizes balance by analyzing the lean angle or lateral acceleration of the bike, all while altering the front and rear braking to help the rider guide the bike safely around curves.
It works in unison with the Cornering Enhanced Antilock Braking System (C-ABS) and Cornering Enhanced Traction Control System (C-TCS) to deliver reliable stopping power while eliminating wheel lock. The C-TCS has two rider-selectable modes: Standard Mode for riding in dry conditions, and Rain Mode for wet, slippery roads.
Seasoned or professional riders can turn off C-TCS to prevent the system from intervening when riding on gravel or dirt roads –- or when executing glorious rear-wheel burnouts to the cheers of friends. The Harley C-ELB, C-ABS, and C-TCS all come standard on all 2020 and later Harley-Davidson CVO models and are optional on certain Harley Touring bikes.
Two-wheel Harley bikes with RDRS Safety Enhancements also get a Drag-Torque Slip Control System (DSCS) that prevents excessive spin of the rear wheels when downshifting or decelerating, particularly when traversing rain-soaked highways or slippery pavements. The system can adjust engine torque when it detects wheel spin, helping to improve grip and traction.
Meanwhile, three-wheel Harley trikes get an enhanced version of DSCS called C-DSCS, or Cornering Enhanced Drag-Torque Slip Control System, which analyzes lateral acceleration. The C-DSCS system is a standard safety feature on all 2020-model-year or newer Harley-Davidson trikes, including the Freewheeler, Road Glide 3, and Tri Glide Ultra.
Rounding off the list of RDRS Safety Enhancements is Vehicle Hold Control (VHC) and a Tire Pressure Monitoring System (TPMS). VHC prevents rolling on slopes or inclined roads by applying brake pressure even when the rider has released the front or rear brakes.
The system maintains the braking pressure until the driver engages the clutch and throttle when pulling away from a stop. VHC can activate automatically when the rider holds the front or rear brake levers momentarily after a complete stop or after hard braking. The VHC indicator light on the instrument panel will illuminate when engaged. As for the TPMS, it does basically what you'd expect it to do — the system monitors your bike's tire pressure and alerts you if one or more of your tires needs air.
