Rohloff - Flat-Mount Adapter

The Rohloff hub was originally designed for a 9mm quick release skewer. 12mm thru-axle support was only made available late 2016, which is achieved via M7 bolts and adapters. Early thru-axles bicycles were released around 2000, Rohloff are slow to adopt new standards waiting over 15 years. Although 12mm rear axles didn't stabilise until 2004. I have contacted Rohloff and they have no plans to support flat-mount in the future. The next step was Cycle Monkey, a company renowned in selling internal hub bikes. They even produce dedicated A12 dropouts replacing the thru-axle adapters [link] I didn't find the adapters too much of an issue.

I queried them and they replied saying that they are working on a flat mount adapter but >6 months later and still no progress. If you didn't know internal hubs need to be directly mounted to the frame to counter input torque. ~The Rohloff hub can make use of an axle plate (OEM2) which connects to a custom post mount brake adapter (monkey bone). This only works post mount brake mounting, Rohloff can provide a “torque arm link” which attaches to the chainstay for non-compatible frames, but it is big and unsightly. This lead me to design my own.

The flat mount brake system is designed for 140mm rotors, an adapter must be installed for use on 160mm rotors. Rohloff supports a minimum rotor size of 160mm. I decided to replace the original SRAM calipers to the SRAM compatible Hope RX4. Rohloff supports a minimum rotor size of 160mm. One issue with this decision the RX4 is that is does not require an adapter and only supports 160mm rotors, essentially having a built in one. This means there is no room to fit a flat-mount monkeybone on top of the brake mount. Also I would assume if Cycle Monkey would ever release an adapter it would only be compatible with standard calipers flat-mount 140mm calipers.

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