|Name:||Ultra New Hubs: Rear Disc, 135mm|
|Over-locknut Dimensions:||135mm Mountain Rear|
|Axel:||Solid, Non-Propietary, Cro-Mo|
|Rear Mountain Axle:||180×10×1|
|Thread:||English Track Cogs (1.37 × 24tpi)|
|Lockring:||Left-Hand-Threaded (1.29 × 24tpi LH)|
|Disc Mount:||ISO 6-Bolt Disc Rotors|
A rear disc mountain bike hub for off-road fixed-gear biking. Yes, you read that correctly. It is a specialized part mass produced by Surly.
A bike frame with horizontal or track dropouts. Frame also needs to be compatible with rear disc brakes or use a rear disc caliper mounting plate.
What is a Fixed-Gear Bike?
According to Wikipedia, a fixed-gear bike has no free-wheel mechanism. In other words, coasting is not allowed as the pedals spin when the bike is in motion. As a result, a weak braking force can be applied by resisting the rotation of the cranks.
Why Did I Buy It?
Fixed-gear mountain biking off-road is fun, though not very safe. I had a bike with track dropouts and wanted make it an off-road fixed-gear bike with rear disc brakes.
Technically speaking, rear brakes are unnecessary on a fixed-gear bike, but it can be stressful on the legs especially when biking off-road. A rear disc brake would greatly help on some of the steeper technical descents.
Please note that a front brake is necessary for off-road fixed-gear biking.
The other benefit to the disc hub is the ability to attach an ISO 6-bolt rear cog to the rotor mount. That would make it a fixed-fixed rear hub, though the rear brake would be lost.
Would I Buy this Hub Again?
Absolutely. I’ve taken it for many off-road rides and it works great. The chainline is around 53.5mm which is rare for a fixed hub, but fully compatible with most MTB chainline systems.