TANDEM  Diversity



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​Gebla Rohbox Shifting System Installation

For those of you who own Rohloff hub-equipped tandems or single bikes, Tandem Diversity can upgrade your bike from the bar-end or bar-top shifter to the Gebla Rohbox system that utilizes brifter levers for shifting. The system includes the Gebla Rohbox gear box, which replaces the Rohloff gear box, as well as modified SRAM brifters which replace the twist shifter and the brake levers.

​Click here for the Gebla Rohbox website.

From my limited experience riding the system, I think there are pros and cons, relative to the Rohloff shifting set up that came on your bike.


1) Gebla uses brifters so you don't have to take your hands off the hoods to shift.

2) The Gebla results in a "clean" cockpit. The bar top is clear, making room for accessories and your hands.

3) Can use carbon bars, with flats and internal cable routing.

4) Can shift standing up.


1) Can only shift one or two gears at a time (The original Gebla unit allowed shifting only one gear at a time. Newer

    ones allow double shifts).

2) No gear indicator.

3) Long shift throw takes a little getting used to.

4) Captain has to be careful not to push too hard on the levers at the ends of the shifting range.*

*Since there is no numerical indicator as to gear in use, the captain has to be cautious about putting too much force on the shift lever at the ends of the range (after reaching gear 1 or 14). To put too much force in an effort to achieve another gear may in fact pull the shift cable loose in the gear box. We've had this happen to 2 customers now, necessitating reinstalling the shift cable. I do note that this is not really different from a traditional chain and derailleur bike with no gear indicator. The captain just needs to learn not to try too hard to shift once he/she perceives the end of the range has been reached.

Other than these considerations, the system appears to behave just like the twist shifters.

The cost to install the Gebla system on your bike is $540. This includes $390 for the hardware and $150 for labor and small parts.

Installation includes:

Gebla system install

Clean belts and apply silicone protectant/lubricant

Limited safety check

     Check headset adjustment

     Check brake adjustment

     Check belt tension

     Check for proper torque on stem and handlebar bolts

     Check cables and housing

     Make any necessary service recommendations

Test ride

Here are more photos to show you what the Gebla system looks like installed: