ShiftFX: A New Take on The Semi-Automatic Motorcycle Transmission

Semi-automatic transmissions haven't made much of an impact on motorcycling, especially with American riders. Aprilia's Mana 850 and subsequent GT version lasted only a handful of years in the Italian manufacturer's US lineup before being dropped in 2015. Although it wasn't a true semi-automatic transmission—it did not have an automatic mode—Yamaha's 2006 FJR1300AE with YCC-S (Yamaha Chip-Controlled Shifting) survived just four years before being quietly discontinued. And the dual-clutch transmission version of Honda's VFR1200 has lagged far behind sales of its standard gearbox brother since the bikes' debut in 2010. Meanwhile, semi-automatic transmissions have taken over the performance automobile segment, with paddle shifters on the steering wheel (and no clutch pedal) now de rigueur for any high-end sports car.

Biperformance Development Corporation's president Dean Pick is hoping to change all that with his company's latest ShiftFX EST (Electronic Shift Transmission). Some of you more astute longtime readers of SR might remember Pick and the original ShiftFX system from our brief first ride back in the November 2007 issue. Although we were impressed with his setup way back then, the new EST system is far more advanced and refined than the original's comparatively crude design. And instead of trying to market the ShiftFX as an expensive aftermarket accessory like the original, Pick is trying to license the new system design to an OEM manufacturer.

Simpler, Smaller, Lighter
The reasons why semi-auto gearboxes haven't caught on with US motorcycle consumers are numerous, but there's one immutable disadvantage to all the previous iterations: added weight. The Mana 850 V-twin scaled in at a portly 516 pounds wet, while the FJR AE weighed 687 pounds with full fuel tank. The dual-clutch transmission on the VFR1200 DCT adds 22 pounds to the standard model's already substantial 591-pound bulk.

There's also the added complexity. The Mana 850 utilized a CVT (Continuously Variable Transmission) setup that had to include space in the cases for the various hubs, pulleys, toothed drive belt, springs, etc. Although Honda did a clever job of hiding them, the DCT has a maze of hydraulic lines and actuators leading to the dual-clutch setup that itself requires an innovative but complicated construction to keep the assembly from becoming excessively bulky. Both of the aforementioned transmissions also have parasitic drivetrain power losses from the mechanical and hydraulic designs.

Meanwhile, the ShiftFX EST system has only four working components (other than the buttons on the handlebar) that can be easily adapted to any motorcycle and have minimal drivetrain power losses. None of the mechanical pieces are large or bulky; the gearbox control and the active clutch controller are about the size of a current starter motor, and the automatic clutch is the same size as a standard clutch. Total weight for the EST system: about 4 pounds.

The overall design of the ShiftFX EST is elegantly simple. Shifting is handled by a patented mechanism consisting of a high-speed DC motor with fixed gear reducer that rotates the shift drum directly. Because it eliminates the ratcheting mechanism in the standard gearbox due to its precise control of the shift drum, the EST can actually shift to any gear from any gear (or to neutral), meaning the ShiftFX EST is no longer sequential in operation. Gearshifts can be accomplished in as little as 50 milliseconds.

Clutch control is handled via a patented electro-hydraulic BDC Active Clutch unit that weighs a little more than a pound. Utilizing a high-tech “shape memory alloy”—the metal changes its length based on the amount of electrical current sent through it—to move the internal hydraulic piston and actuate the bike’s clutch, the Active Clutch also features an isolation valve that allows the unit to be installed inline with a standard OEM hydraulic clutch actuation system. The isolation valve also allows the usage of a standard clutch lever to override the Active Clutch unit at any time, for aggressive launches, slow parking lot maneuvers, etc.

The ShiftFX EST also uses an APTC+ (Adler Power Torque Clutch) auto-clutch in place of the standard clutch basket assembly. This auto-clutch unit permits smooth launches in automatic transmission mode, in addition to its slipper clutch benefits on deceleration and its anti-stall properties while coming to a stop. Why not just have the BDC Active Clutch handle these chores? “We are using the Active Clutch as a torque control device during shifts,” Pick says. “For it to do launch control and anti-stall duty, it would need to be larger and draw more power from the motorcycle, which goes against our design goals.”

Controlling these three components is a compact and fully programmable Transmission Control Unit. The TCU is able to provide any type of shifting characteristic based on speed, load, gear position, throttle position, and other parameters. Plus, the TCU is fully capable of communicating with the bike’s ECU via OEM CAN bus wiring, meaning it can control engine-braking and throttle movement to match transmission and road speed during downshifts, as well as work within any OEM rider aid electronics suite’s riding modes.

So How Does It Work?
We were given the opportunity to sample the latest-generation ShiftFX EST on a late-model KTM Duke 690 test mule. One of the design goals with the EST was to allow easy OEM component interfacing and require no changes to existing engine architecture; a cursory examination of the engine revealed the only visible difference to be a custom clutch cover housing the APTC+ auto-clutch and the gear controller. And although we use the term "custom," the cover wasn't that much different, with the small bulge on the lower half for the gear controller the only real clue (other than the lack of shift lever) that this KTM was different than any other.

Because Pick is intending to license the EST to an OEM manufacturer, some of the controllers were very basic in design and not intended to look polished and pretty. For example, a three-way switch mounted just underneath the Duke 690’s instrument panel controls the EST’s transmission mode (“N” is for neutral to start the engine, “A” is for fully automatic gearbox operation, and “+/-” for semi-automatic shifting), but a manufacturer would surely create its own more elegant selector design. Likewise for the three buttons mounted on the left handlebar that activate upshift/downshift/neutral. While Pick feels that using the rider’s thumb is less obtrusive physically and mentally, we would prefer thumb/forefinger paddles like the Honda VFR DCT or Aprilia’s paddles for traction control on its RSV4 series.

After starting the KTM in neutral and then switching to semi-automatic, we trolled around the office parking lot to test the low-speed action of the APTC+ auto-clutch. Even though you can override the auto-clutch with the standard clutch lever at any time, we never really saw the need to as long as we were careful with throttle inputs. Clutch engagement was fairly smooth and allowed easy tight turns, with none of the jerky clutch action that plagued the Yamaha FJR AE.

While negotiating Southern California’s urban traffic and then during our first foray into the local canyons, we found that the ShiftFX EST’s shifting action needed to be sped up significantly when riding at a medium pace, with too much lag between gear changes. Pick quickly plugged in a laptop and began making changes to the mapping. Associate Editor Michael Gilbert took the KTM test mule out on its second run and reported that the shift action was improved. “I was impressed with the seamless feel of shifts as I clicked through the gears,” Gilbert enthused. “The button responded immediately to my thumb input and reacted by giving me a clean, crisp shift every time.”

Still, after having tested some of the best OEM quickshifters on various literbikes, he felt it could have been even better. "Of course it isn't intended to have race performance, but during upshifts it still had a very slight delay in power delivery between gears." We didn't have time to allow Pick to make more mapping adjustments, but he assured us the shift action could be sped up as quick as we wanted. We had no such problems downshifting in semi-auto­matic mode, with the transmission easily handling hard braking and rapid-fire downshifts while smoothly matching engine and road speed.

One area where the ShiftFX EST did stand out is in taking off from a stop. The APTC+ auto-clutch was dialed in well and enabled very quick launches off the line with no bogging or excessive slipping. In fact, we would likely be hard-pressed to better it using the manual clutch lever. This was a welcome surprise from the usual lackluster acceleration exhibited by other semi-automatic bikes off the line.

In fully automatic mode, the ShiftFX EST worked seamlessly, though Pick admits that he “intends the automatic to be better suited for novice riders and for cruising at a sedate pace,” and the shift mapping reflected that design brief. Running around city traffic and zipping along suburban streets was easily handled, but any type of spirited riding in the canyons showed the automatic transmission mode to be out of its element. “As I would accelerate from a curve at high rpm then let off to enter another, the system would consistently upshift, causing me to freewheel into the corner,” Gilbert complained. Aggressive braking also revealed some mapping drawbacks, with Gilbert griping that, “I also found that on deceleration to hard stops, I was wanting downshifts to happen faster. The slow process forced me to brake earlier to make hard stops because of the lack of engine-braking.” Again, Pick assured us these were aspects that he could easily change with some mapping edits.

A Semi-Automatic Gearbox In Our Future?
For a motorcycle manufacturer, the ShiftFX EST presents some definite advantages over other semi-automatic transmission designs. It retains the standard manual clutch lever to override the EST at any time and is easily adapted to any engine architecture and transmission without requiring major modifications. There are no hydraulic pumps or drivetrain power losses, and the ShiftFX EST's electrical requirements are easily met by a typical motorcycle's charging system. Finally, the entire system is compact and weighs less than 4.4 pounds.

While we would love to see this technology tried on a tuned-to-the-edge 600cc or smaller sportbike where constant gear changes can be a distraction, it’s doubtful that a manufacturer would take the chance until it was proven that the system would be accepted by the market. Thus it’s more likely that the benefits of the ShiftFX EST would be more applicable to bikes on the novice/higher-volume side of the market, where the automatic transmission mode can be used as a selling point. One European motorcycle manufacturer has already been testing the ShiftFX EST for possible use in a production bike. But Pick is hoping that others might like to join the semi-automatic party.