KTM planning semi-auto bikes
Patents have emerged revealing that KTM is developing a semi-automatic transmission option for its 1,301 cc V-twin powered models - potentially giving the company a tool to compete with Honda's popular DCT gearboxes with a fraction of the complexity.
Honda's dual-clutch transmissions allow seamless gearchanges by allowing two ratios to be engaged simultaneously. Essentially, it's like having two gearboxes in parallel, each with its own clutch, so the electronics can feed in one clutch while disengaging the other to provide a shift without any interruption in the power reaching the rear wheel. Its clever, but also heavy, costly and complex. Even so, it's a system that's proved popular, particularly with buyers of the Africa Twin, where DCT versions account for close to half the total sales.
KTM's 1290 Adventure is a key rival to the Africa Twin so perhaps it's unsurprising that the Austrian company is working on its own semi-automatic gearbox. However, the KTM design is far simpler than Honda's. Instead of the complex DCT, it relies purely on the increasingly competent ability of modern quickshifters to achieve clutchless changes. With the ability to modulate throttle and ignition, quickshifters able to make rapid, clutchless upshifts and downshifts are already commonplace, so to achieve a semi, or even fully-automatic box, KTM only needs to add a system to allow the bike to start and stop, plus a mechanism to electrically replicate the shifts usually made by the rider's foot.
The company's patent explains that the problem of starting and stopping without a clutch lever is achieved simply by using a scooter-style centrifugal clutch. This is something that's already been tried, and MV Agusta even offers models with its own 'SCS' transmission - using a Rekluse centrifugal clutch and an up/down quickshifter - to eliminate the need to use the clutch lever at all.
The second problem - automating the gearshifts - is solved by adding an electronic actuator to turn the shift drum inside the transmission, replacing the usual foot-operated mechanism. That allows gearchanges to be made at the touch of a button or fully automatically, using a map of throttle position, revs and road speed to decide on the appropriate ratio at any particular time.
One element that KTM's design has been forced to add is a transmission locking system. The adoption of a centrifugal clutch means that when the engine's turned off, the clutch is disengaged, so you can't simply leave the bike in gear if it's parked on a slope. The transmission lock solves that problem. It uses a pawl inside the gearbox that drops a claw into the teeth of one gear, locking it solid.
The pawl is moved by the shift drum, only allowing the lock to be engaged when a 'park' position is chosen. Electronics prevent the system from shifting into park when the bike is in motion, rather like a car with an auto transmission.
Such is the detail of the drawings in KTM's patent application, it's even possible to read the part numbers on some of the components. It's from these part numbers that we know the main elements of the gearbox are taken straight from the 1,301 cc '1290' models, with the 1290 Super Duke R and 1290 Super Adventure both using the same components.
KTM is known to be working on a touring derivative of the Super Duke at the moment, which is a potential target for the semi-auto transmission, and the Super Adventure could also benefit from the system as it aims to steal buyers away from the Africa Twin.
