Rohloff Monkey Bone 180 mm – IS to PM adapter
The Rohloff Monkey Bone 180 (8554) anchors a SPEEDHUB 500/14 with OEM2 axle plate on an IS2000 frame brake mount and positions a post-mount caliper for a 180 mm rotor – a strong setup for loaded touring bikes and e-bikes.
Why the Monkey Bone 180?
More braking reserve. A 180 mm rotor handles heat and heavy loads better – useful for touring bikes with luggage and e-bikes. 
Integrated torque support. The OEM2 axle plate locks into the Monkey Bone; no extra torque arm is needed. 
Rohloff-approved for e-bikes. One of the three torque supports Rohloff allows for OEM2 hubs on e-bikes and tandems. 
Standard bolts. Fixed with M6 bolts at 6 Nm; the bolts usually come with your disc brake.
Who is it for?
- Touring cyclists with luggage. Strong braking and a strong torque support in one compact part.
- E-bike riders. Higher speeds and weights call for a bigger rotor.
- Workshops. A common part for SPEEDHUB disc-brake builds.
Compatibility
| Hubs | SPEEDHUB 500/14 with OEM2 axle plate: O.L.D. 135, 142, 148, 170 and 177 mm |
|---|---|
| Frame brake mount | IS2000 (International Standard) |
| Brake caliper | Post mount |
| Rotor size | 180 mm |
| Bolts | Not included: frame M6x18–20 and caliper M6x16 bolts (usually supplied with the brake) |
| Torque | 6 Nm (frame and caliper bolts) |
| Not compatible | IS calipers; frames with integrated/direct post mount |
Frequently asked questions
Which bolts do I need?
Two M6x18–20 bolts to the frame and two M6x16 bolts for the caliper, all at 6 Nm. These are usually supplied with the brake, not with the Monkey Bone.
Which tools does Rohloff list?
A 5 mm Allen key, a TX20 key and a torque wrench.
Can it be used on an XXL fat bike hub?
No – for 190/197 mm hubs use the Monkey Bone -10 for 180 mm rotors (8554-10).
About Rohloff
Rohloff AG designs and builds the SPEEDHUB 500/14 in Fuldatal, Germany: a 14-speed gear hub with a 526% gear range that has proven itself for more than 20 years on touring, tandem, cargo and e-bikes.
BoodaBike (Massive Bikes, Budapest) is an official Rohloff service centre, trained by Rohloff, and an official European distributor of Rohloff hubs and genuine spare parts. Not sure which part fits your hub? Send us the serial number and a photo of your hub and we will check it for you.