BMW Motorrad, the motorcycle division of BMW, has recently secured a patent for rear-wheel steering technology in motorcycles. This innovative development showcases BMW's exploration of rear wheel steering with various motorcycle layouts, including chain-driven, belt-driven, and shaft-driven designs. The primary objective behind this technology is to achieve a lower turning circle, improve handling, and enhance motorsport capabilities.
Exploring Potential Use Cases
BMW's patent includes sketches of a cruiser bike, indicating that this technology could be applied to such motorcycles. This idea may have stemmed from the launch of BMW's R 18 cruiser range, which typically features a long wheelbase, a large rake angle, and a small trail angle. These characteristics often make maneuvering challenging for cruisers, and rear-wheel steering can significantly address this issue. The patent also mentions potential aerodynamic benefits, as the front wheel can be covered due to the lower steering angle and the involvement of the rear wheel. Additionally, the patent highlights the advantages of rear wheel steering in motorsports scenarios when the front wheel is in the air.
BMW Motorrad's Electric Rear Steering
BMW has also filed a patent for an electric motorcycle, and the introduction of rear-wheel steering technology aligns with the brand's ongoing research and development efforts. However, neither the electric motorcycle nor the rear wheel steering technology has entered production yet.
Considerations and Limitations
While the concept of rear wheel steering in motorcycles is intriguing, there are several factors to consider from an engineering perspective. Apart from the complexity, cost, weight, and maintenance associated with implementing such a system, one primary concern is the strength of the swingarm. BMW's patented rear wheel steering mechanisms would replace conventional swingarms, potentially raising durability issues.
Moreover, riders are accustomed to leaning and shifting their body weight to initiate turns, which is the traditional method of steering motorcycles. Transitioning to a new steering mechanism would require time and adjustment, as it challenges riders' instincts and muscle memory.
Adapting to the New Steering System
Riders who employ counter-steering techniques, where they steer right to turn left, may find it easier to adapt to this new steering system. However, counter-steering is a less common practice. On the other hand, stuntmen who engage in dragging and drifting maneuvers and off-road riders who rely on rear wheel lock to steer motorcycles may quickly adapt to this new mechanism.
Multiple Methods of Implementation
BMW's patent reveals various methods to achieve rear wheel steering. These include double-sided and single-sided mechanisms with physical linkages to the handlebar for steering input. Additionally, one patent proposes electrical assistance for rear wheel steering, eliminating the need for physical linkages by utilizing steering input from a position sensor, similar to car steering systems.
While BMW's rear wheel steering technology holds promise for tighter turns, improved motorsport performance, and potentially enhanced aerodynamics, its practical implementation, acceptance by riders, and addressing the associated challenges remain crucial factors to consider before its widespread adoption in the motorcycle industry.
