Monkey Bone - Postmount brake adapter

The Monkeybone offers a simple method of anchoring the axle of the Rohloff SPEEDHUB 500/14 to a frame through the disc brake mount. In order to use the Monkeybone, your SPEEDHUB 500/14 will need an OEM2 axleplate, your frame must have an International Standard disc brake interface, and your disc brake caliper must have a Postmount interface. The Monkeybone is not compatible with IS direct-mount disc brake calipers or frames with Postmount disc brake interface.

Assembly instruction Monkeybone for 160/180mm discbrake (English):

Required Tools:

5mm Allen wrench
Torque wrench
TX20 Torx wrench

Required Parts:

Frame with IS51 disc caliper interface
Disc brake caliper with Postmount interface
Rohloff SPEEDHUB 500/15 with OEM2 axleplate
Monkey Bone
2x M6x16 bolts (sold separately; typically included with disc brake caliper)
2x M6x18-20 bolts (sold separately; often included with disc brake caliper)

Installation Instructions:

1. Ensure that you have the Monkeybone that is appropriate for your disc rotor diameter (160mm or 180mm; 203mm rotors can be used with 180mm Monkeybone and spacers (sold separately).

2. Attach the Monkeybone to the frame using two M6x18-20 bolts. Ensure the slot for the OEM2 axleplate faces the dropout. Tighten bolts to a torque of 6 Nm/51 in-lbs.

3. Connect disc brake caliper to Monkeybone using two M6x16 bolts. Leave bolts loose enough that caliper can slide for adjustment later.

4. Install wheel into dropout taking care to align slot in end of OEM2 axle plate with cutout in Monkey Bone and the disc rotor between brake pads.

5. Check position of EX shift arm with OEM2 axle plate engaged with slot in Monkeybone; reposition axle plate as needed for desired cable routing using the TX20 Torx wrench (see Rohloff Owners Manual).  Tighten axle plate screws to a torque of 3Nm/25 in-lbs.

6. Fully seat axle in dropout before tightening quick-release lever or axle nuts.  Threaded axle nut torque: 35 N-m/310 in-lbs; Pitlock or bolt-on skewer torque: 7 N-m/60 in-lbs.

7. Follow brake manufacturer’s recommendation for setting brake caliper position.  Tighten brake caliper bolts to a torque of 6 N-m/51 in-lbs.

Use of the Monkey Bone with some frame geometry can result in the wheel being pulled out of the dropout while pedalling due to the forces exerted by the Rohloff SPEEDHUB 500/14 onto the frame. When the anchoring point of the OEM2 axleplate is located in front of a line parallel to the dropout slot, there is a component of the reaction force in the lowest gears that tends to push the axle down and out of the slot. Per Rohloff’s recommendation, the Monkey Bone and OEM2 axleplate combination are not recommended for use on frames with such geometry (see page 30 of the Rohloff Owners Manual for more info). Use of the MonkeyBone and OEM2 axleplate is entirely at the user’s own risk. The forces applied to the disc brake mount by the Rohloff SPEEDHUB 500/14 can damage some frames. Please contact your frame manufacturer to determine whether this setup is appropriate for your frame and whether its use affects your frame warranty.

Further information: