17 Apr 2014

First look: Gear Shift Assist Pro on the BMW R1200GS

The original Gear Shift Assist system has been available for a number of years on several BMW models of the K- and S-series, enabling clutchless upshifts by briefly cutting the fuel supply when the system senses an upshift via the foot lever.

Gear Shift Assist Pro (GSAP) is the next generation of this system, announced with the introduction of the updated R1200RT last November. The Pro version allows for both upshifts and downshifts and according to BMW this is a world first on a production motorcycle.

The R1200RT and the R1200GS are mechanically similar bikes, sharing an engine (with a couple of differences) and parts of the suspension system and frame—BMW has made available GSAP as an ex-works option for the first time on a GS. It is not compatible with the 2013 models, but only the 2014 update (models with the steering dampener)—namely those built from approximately 15 August 2013. There is no official word why this is the case, but I suspect it is simply that the 2014 spec bikes have a connector fitted in the wiring loom for the CAN-bus.

The Gear Shift Assist Pro unit

The GSAP system intrigued me greatly so I put in an order. I was informed that my bike was within the first 300 built which support the system—lucky me! BMW had some delays relating to the software which held up the order for a few weeks but the people in the service department at BMW Battersea (thanks Phil, Shanon and James!) had it installed on my bike within 24 hours of receiving the unit. Good communication and good service are what make this dealership excellent!

Below is BMW’s (rather thorough) explanation is included as part of the press kit for the new RT:

Optional Gear Shift Assistant Pro for changing gear with virtually no interruption in power flow.

The BMW Gear Shift Assistant Pro is another world first for production motorcycle manufacture. Compared to the Gear Shift Assistant already featured on the superbike models such as the BMW S 1000 RR, the system’s functionality has been extended for use on the new R 1200 RT and adapted to the specific requirements of a touring bike. The Gear Shift Assistant Pro enables upshifts and downshifts to be made without operation of the clutch or throttle valve in the load and rev speed ranges that are of relevance to riding, both increasing comfort for the rider and providing an added touch of dynamism. The majority of gear changes can be carried out with the help of the Gear Shift Assistant—starting off is one of the few exceptions to this.

When accelerating, the throttle valve no longer needs to be closed for gear changes, allowing the power to flow with barely any interruption. And when decelerating and shifting down a gear (throttle valve closed), automatic double-declutching is used to adjust the engine speed. Gears are engaged in the usual way with the footshift lever. Shift times are considerably faster compared to gear changes with operation of the clutch. The Gear Shift Assistant is not an automatic shift system, but rather just an aid for changing gear. When gear changes are carried out with the help of the Gear Shift Assistant, the cruise control is automatically deactivated for safety reasons.

The system works by employing a sensor on the gearbox output shaft to detect the rider’s shift request and trigger the assistance mechanism. By increasing or reducing engine torque by the required amount, the load on the powertrain is effectively eliminated to allow the shift dogs of the next gear wheel pair to intermesh in the same way as when the clutch is used. No gear shift assistance is provided when changing gear while operating the clutch, or when shifting up with the throttle valve closed (overrunning) or when decelerating. Neither will any assistance be given if the shift lever is not in its proper starting position when shifting up or down.

Assistance is available when downshifting with the throttle valve open, but this can provoke severe load change reactions, particularly in low gears. The same effect may be produced when changing down without operating the clutch while cruising at a constant speed. BMW Motorrad therefore recommends always using the clutch to change gear in these riding situations. Riders should also avoid using the Gear Shift Assistant at rev speeds close to the red line.


So what’s it like to ride with GSAP? 

In a word (okay, two words) bloody amazing! Being a ‘school’ night I’ve only ridden about 20 miles around London so far with the system but I can’t wipe the smile off my face.

The sound is similar to dual clutch systems used on BMW M cars, higher end Audis and Volkswagens etc—complete with a pop from the exhaust on each gear change. And it’s fast, I’d say not much more than 1/10th of a second when upshifting. Combined with the high torque of the boxer engine, this translates to turbine-like, seamless acceleration from a standstill, smoother and faster than is humanly possible using the clutch.

It does take a little practice to acclimatise to the system and learn its quirks.

At a constant speed the system is not happy to make a gear change and this can result in some not-so-nice driveline shock. When decelerating the system doesn’t operate at all for upshifts.

Downshifts while decelerating with a closed throttle are accompanied by an automatic blip of the revs and the shift is slightly slower than upshifting to accommodate this—I’d say downshifts take 2/10ths of a second. It’s possible to downshift at a constant throttle, or around 10% throttle, but this can also cause a bit of driveline shock.

Gear changes using the system require dedication—no half-arsed attempts. You need to commit to the gear change in one smooth go, and the lever feels slightly heavier when using GSAP than when using the clutch normally. During one halfhearted 1st–2nd change I ended up in neutral—call it operator error.

However, learning its quirks has only taken about 20 miles of city riding (and associated frequent gear changes)—nothing in the grand scheme of things. In that short time it now almost feels agricultural to change gears with the clutch.

With Easter weekend looming—four days off (yay!)—and favourable weather in the forecast, I will have a chance to get out of the city on roads where this system will be in its element. Watch this space!

Brief update one day on

They—presumably experts—say during sleep your brain processes the things you learned that day. I guess they have a bit of a point. Riding to work and back today, everything just clicked—no herky-jerky, no missed shifts—everything as smooth as silk.

If only all things in life had such a comfortable learning curve.

Did I mention I like the GSAP system? Still smiling here!

Further information