We have had a Rohloff hub on our Speedster tandem for several years and cycled at least 15,000 miles in that time. The Rholoff addressed the chronic shifting issues I had previously experienced centered on the triple crank. It reliably failed to shift to the granny gear when starting up a steep hill, a rather frequent event here in West Virginia. With our Rohloff setup we had Co-Motion’s version of the twist handlebar shifter which once set correctly was tough and reliable. However, it needed fine tuning during reassembly at the beginning of a tour and I still hadn’t mastered the fine art of getting it set just right. Sometimes I would end up only having 13 of the 14 gears working or the gear indicator arrow only roughly pointed to the correct selected gear. If I succeeded in adjusting it correctly I often didn’t know what I had done that was key to that success. I had to wear a bicycle glove to get enough friction if the shifter was at all wet from rain or sweat. But that wasn’t my main issue with the shifter. I don’t like having to take my hand off the handlebar or brake hood to twist the shifter. I tend to swerve the tandem, an unnerving experience when grinding up a hill with traffic passing too closely. On a recent tour we had a set of heavily loaded rear panniers which exacerbated the situation. A tandem friend showed me the Gebla Rohbox he had installed on his bike, so when we returned from the tour I decided to make the switch. Here are observations about the process.
-I purchased the Gebla Rohbox from Cycle Monkey. The kit cose $575 which included the Rhobox shifter.
The Rohbox replaces the shifter box attached to the bottom of the Rohloff hub. The case turned out to be slightly smaller at the top which was an advantage in my case as the original shifter was too snug against the wheel stay. The instructions were translated from German, but with the pictures I was able to figure out the minimal modification necessary, which for a 4 year old Rohloff required removing a small plastic ring insert.
-Cycle Monkey made the modification to the SRAM Rival 22 Mechanical Brake Shifter (Brifters) which was a relief. Unexpectedly, they also included brake and shifter cable and housings sufficient for a single bike.
-The directions indicate the system should be installed by an experienced mechanic. Good luck finding an experienced tandem bicycle mechanic or any mechanic who had seen a Rohloff anywhere near here, so I had to do. In my case what I had learned about derailleur adjustments over the years helped, but there was still a learning curve. Gebla relies on two shifting cables. I elected to have the right SRAM brifter pull cable to shift to one or two higher gears. The left brifter pulls cable to shift to one or two higher gears. Each cable pull engages a pawl against an oversized cog which replaced the smaller cog on the original Rohloff shifter. This larger cog provides the increased leverage necessary for shifting with a brifter.
The oversized cog is in the center. The pawl that engages the cox is just visible next to the spring and attached to the bronze colored block that secures the shifter cable.
-When I first looked at the Gebla Rohbox and even after installing it, I feared the pawls would be too fragile to stand up to repeated shifting, especially if I tried to shift from gear 14 to 15, which doesn’t exist. Apparently, the engineer had me in mind because it seems to be more robust than it initially appeared. It’s likely that I’m not able to put enough force on the brifter shifter paddles to bend the pawls. The oversize cog also lessens the amount of force needed to shift the gears.
-Once I made the correct adjustments by turning the barrel adjusters the shifting has been excellent, even on our hilliest routes. I no longer feel like I have to be overly gentle with the shifter. Although I frequently don’t realize when I’m in gear 1 or 14, an additional shift attempt feels different and I stop long before damaging a pawl. Before a long or international tour I will probably order a spare Rohbox shifter. It’s compact, light and costs only $253.
-With the Co-Motíon twist shifter I liked being able to shift a lot of gears at one time, usually about four gears. Now I’m limited to one or two gears. I’ve noticed that when stopped at an intersection I quickly got used to just doing multiple shifts to get to an appropriate starting gear. Since I no longer have to move my right hand to twist the shifter I tend to shift more often. In our hilly area I usually made two shifts at a time while now I tend to more often make one shift. I no longer have problems with the tandem swerving while shifting.
-The Co-Motion twist shifter was robust and required only minimal maintenance. However, it did start to make some noise when shifting when the cables aged and perhaps needed some lubrication. After several years I had significant difficulty getting one of the old cables out of the shifter when I wanted to replace them. This time, after only six months one of the cables would not come out in spite of using every kind of lubricant and penetrating fluid I threw at it. I had hoped to keep the twist shifter in reserve on the shelf but ended up just throwing it away. That old cable is never coming out and I could see no way to take apart the shifter. I’m glad that didn’t happen somewhere on a tour.
The switch to the Gebla Rohbox has been a complete success. I always hoped Rohloff would finally release an electronic shifter for our system, but I’m no longer sure I would bother to make a change to an electronic shifter.
Dave Fritsch