Ride by Wire

In the automotive industry refers to the use of electrical or electro-mechanical systems for performing vehicle functions traditionally achieved by mechanical linkages/actuators. This technology replaces the traditional mechanical control systems with electronic control systems using electromechanical actuators and human-machine interfaces such as pedal and steering feel emulators. Hence, the traditional components such as the steering column, intermediate shafts, pumps, hoses, belts, coolers and vacuum servos and master cylinders are eliminated from the vehicle. This is similar to the fly by wire systems used widely in the aviation industry.

Ride-by-wire involves no direct, physical connection between the twistgrip and the throttle butterflies at the engine end. Conventionally there's a Bowden cable connecting twistgrip to butterflies, or the carburettor slide on much older bikes, but with ride-by-wire, the twistgrip operates a transponder which converts the movement to an electrical signal. This goes to the engine management computer which decides exactly what the rider is trying to achieve. It then sends its own electrical signals to a stepper motor which operates the inlet butterflies. So the twistgrip is joined to the butterflies only by electrical wires with a computer in between.

Whilst the next clip reference a motorcar, the concept is clear - only replace the throttle pedal with your twistgrip.

There are various advantages, including the facility to have cruise control, some types of traction control, push-button power capping and so on, but it also mean larger intake tracts can be used. With a conventional system, if you snap open the throttle when a bike has large diameter intakes the airflow tends to stall and the bike at best stutters, and in more extreme cases an even stall. This was common on older race bikes. But ride by wire interprets your grab at the twistgrip as maximum acceleration needed, then it opens the butterflies only fast enough to prevent the air flow stalling. You could in theory do this manually, but it would drive most riders mad.

In turn, this means more power and better efficiency as the inlet gas flows in more easily. An extreme case is the RSV4 Aprilia - that engine is a bit like those jet fighters that are inherently unstable without constant computer control of their control surfaces, as the RSV4 has such huge intakes it would be unusable with normal throttle control cables.

Whilst the term "ride by wire" is commonly used, the use of electro-mechanical technology is applicable just about in any function to the executed on a vehicle such as;

• Brake by wire - eliminating the need for hydraulics

• Shift by wire - typically in an automatic gearbox such as "Park", "Reverse", "Neutral" and "Drive"

• Steer by wire - providing steering control in a car with less mechanical components/linkages between the steering wheel and the wheels

• Throttle by wire - electronic throttle control without any cables between the throttle and the throttle valve in the engine

Sources: Ash on Bikes, Engineering Explained, Wikipedia