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What is a Counter-Rotating Crankshaft and Why Use One?

What is a Counter-Rotating Crankshaft and Why Use One?

Motorcycle engineering technology has made unprecedented progress over the years, offering greater stability, maneuverability, and higher power outputs to motorcycle enthusiasts. Moreover, with the growing inclination towards motorcycling, emission standards have also become stricter, compelling motorcycle manufacturing companies to find out ways to meet the revised emission standards without compromising speed and power outputs. Initially, only suspension setup and chassis design were the points of focus when a bike’s agility and improved handling were under question. However, engineers are now tweaking engines to contribute towards better maneuverability and handling.

The introduction of counter-rotating crankshafts on different speed-focused and agile motorcycles is just one of many steps that motorcycle brands are taking toward creating faster bikes with fewer emissions. Counter-rotating crankshafts first appeared on race tracks but are now making their way into production motorcycles due to their notable advantages in terms of refined handling, smoother riding experience, reliable traction control, and greater cornering performance. Despite their growing popularity, counter-rotating motorcycle crankshafts are the least understood mechanical parts on a motorcycle. This article will delve deeper into the workings of a counter-rotating crankshaft and also help you familiarize yourself with its many benefits.

1. What is a Counter-Rotating Crankshaft?

Standard production motorcycles feature a crankshaft that moves in the forward direction, the same as the wheels. However, the counter-rotating crankshaft is a mechanical component that moves in the opposite direction of the wheels.

In a typical inline four-cylinder power plant, there are four pistons connected to the crankshaft that change the horizontal motion of the pistons into rotational or circular motion. It was observed that this engine configuration was so heavy that forward rotation of the crankshaft added to the gyroscopic force, affecting the handling and making it difficult to steer the motorcycle.

To reduce this resistive force and cancel out its obstructing effect, engineers eventually came up with the concept of a crankshaft that rotates in the reverse direction of the wheels. This change helped reduce the gyroscopic force, which in term eliminated the phenomena of power wheelies when riding the motorcycle at higher speeds.

1.1 What is the Gyroscopic Effect?

The gyroscopic effect is the force created as a result of the rotation of the motorcycle wheels. On the one hand, the gyroscopic effect is responsible for keeping a moving motorcycle upright, but it also makes it difficult to lean on a moving bike. Since the gyroscopic force is directly dependent/proportional to the mass of the spinning motorcycle wheels and their angular velocity, a rider has to put in greater effort to lean the bike against this effect.

While installing lightweight wheels can help reduce this resistive force to some effect, it will be of little use because there is another component - the crankshaft - that has a large mass, angular velocity, and the ability to produce this obstructing force. Therefore, to fully optimize a bike’s handling, it is necessary to tackle the gyroscopic effect produced by the engine as well.  

2. Why Use a Counter-Rotating Crankshaft? Potential Benefits

A counter-rotating crankshaft offers many benefits simply by neutralizing the gyroscopic force. It is reported that motorcycles featuring a reverse-rotating crankshaft are more agile, easier to handle, and offer greater traction for stability, allowing riders to achieve higher speeds and unleash the potential of their bikes with greater confidence. Though these crankshafts are not commonly used on production bikes, it is evident what the future holds for most two-wheelers in terms of crankshaft design. 

2.1 Offers Greater Maneuverability and Agility

Counter-rotating crankshafts help improve the stability and maneuverability of the motorcycle, making it possible to safely maneuver sharp corners at higher speeds. Moreover, these crankshafts allow riders to quickly transition from side to side. If these crankshafts were installed on adventure touring motorcycles or sports bikes, they would make traversing twisties and winding roads a safe and enjoyable experience. Offering greater control in demanding conditions, counter-crankshafts will eventually become a feature of preference for riders who enjoy canyon carving and racing. 

2.2 May Help Reduce Engine Vibrations

The counter-rotating crankshafts help reduce engine vibrations at higher speeds by neutralizing the resistive forces resulting from the rotational motion of the wheels. By reducing the vibrations, counter-rotating crankshafts can help with rider fatigue and offer a relaxed riding experience if installed on production bikes.

2.3 Helps Optimize Traction

Counter-rotating crankshaft optimizes traction control under demanding riding conditions, allowing riders to safely apply hard braking and quickly achieve higher acceleration. Since the gyroscopic forces become weak due to the contra-rotating crankshaft, they become negligible and fail to hinder engine power delivery to the wheels, offering a stronger grip and enhanced stability. 

2.4 Emission Standard Compliance with High Power Outputs

As discussed, counter-rotating crankshafts help motorcycle manufacturing companies meet strict emission standards without reducing or compromising the power outputs of their motorcycle. Due to being equipped with reverse-rotating crankshaft technology, the BMW S1000RR generates about 205 hp, while the Honda CBR1000RR-R Fireblade generates about 214 hp at 14,500 rpm, even though both these motorcycles comply with the latest Euro 5 emission standards. 

2.5 Reliable Cornering Performance on Race-Tracks

Reliable Cornering Performance on Race-Tracks
Photo Credits: Honda Powersports

Counter-rotating crankshafts were essentially designed for performance-oriented racing bikes. From greater engine performance to better handling, improved traction, dull vibrations, cornering performance, and effortless steering, all the benefits mentioned above have already been tested and acquired by motorcyclists on the race tracks.

3. Are There Any Disadvantages of a Counter-Rotating Crankshaft?

The introduction of counter-rotating crankshafts in motorcycles helped improve handling and maneuverability by reducing the gyroscopic effect; however, it created the need for additional gear that could convert the reverse rotation into forward motion to drive the wheels. As a result, motorcycle engineers installed a jackshaft that helps move the wheels in the forward direction. Despite their well-designed structures, jackshafts tend to drain up to two percent (2%) of the engine’s power output, reducing the efficiency of the motor. However, because this small compromise makes up for the lost power in terms of enhanced handling, most engineers and riders easily ignore it. Therefore, whether a loss of power outputs a disadvantage is largely debatable, considering no system offers 100% efficiency. 

4. Which Motorcycles Feature a Counter-Rotating Crankshaft?

Which Motorcycles Feature a Counter-Rotating Crankshaft?
Photo Credits: MV Agusta

Due to the prominent benefits of counter-rotating crankshafts, many motorcycle manufacturers, especially those who compete and excel in manufacturing high-tech racing motorcycles for MotoGP, have embraced reverse-rotating crankshaft technology, including Honda, Suzuki, Yamaha, KTM, Ducati, and Aprilia. However, these brands have yet to offer this feature in their production motorcycles. If you want to see a production bike with a counter-rotating crankshaft, then the performance of the Ducati Panigale V4 should be of interest to you. Another note-worthy example is the all-new 2024 MV Agusta’s LXP Orioli, which debuted at the 2023 EICMA, demonstrating high-performance motorcycle engineering with a counter-rotating crankshaft.  

5. Last Words

The introduction of a counter-rotating crankshaft highlights significant advancements in the motorcycle industry. Conventional production motorcycles come with crankshafts that move in the same direction as the wheels. This movement increases the gyroscopic force, making it difficult to steer the bike. On the other hand, a counter-rotating crankshaft, moving in the backward direction, effectively cancels out the gyroscopic effect produced by the wheels moving in the forward direction. Hence, the bike feels lighter, flickable, and easier to lean in corners.

Counter-rotating crankshafts have many benefits, ranging from a smoother ride to effortless steering, better traction, and high power outputs despite fewer emissions. Currently, this technology is limited to race-worthy motorcycles by Honda, Yamaha, Suzuki, Ducati, Aprilia,  and even KTM. As for street-legal motorcycles, counter-rotating crankshafts are only available on the Ducati Panigale V4 and street-legal MV Agusta bikes; however, the direction of motorcycle manufacturers is clear, and it is only a matter of time before a majority of production motorcycles will boast this high-end engine technology.

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