The Monkey Lab: Rohloff-Equipped Surly Krampus 29+ Mountain Bike

We were fortunate enough to get our hands on this Surly Krampus frameset, a pair of Rabbit Hole rims, and a pair of Knard tires from the first production batch of these parts. The bike was built for a customer in Calgary, Alberta, Canada for bike-packing, including plans to ride the Tour Divide event aboard it. The 2745 mile Tour Divide is a self-supported, mostly off-road race that follows the Great Divide Mountain Bike Route along the spine of the Rocky Mountains from Banff, Alberta to Antelope Wells, New Mexico. The rigors of long days of off road riding in a variety of weather conditions during this event can wreak havoc on a bike, especially the drivetrain. The Rohloff SPEEDHUB 500/14 offers an ideal drivetrain for this type of event/riding as the moving components are all housed inside the hub, sealed from the environment. Last year's winner and new course record setter, Oliver Walley, won aboard a belt-drive/Rohloff-equipped bike, showing that the SPEEDHUB offers the high efficiency and reliability needed for such an extreme event.

For the wheels, we laced up the Rohloff SPEEDHUB 500/14 and a Chris King ISO disc front hub to a pair of Surly's new Rabbit Hole rims using Sapim Laser thin double-butted spokes and brass nipples. The Rabbit Hole rims are a single-wall, wide 700c/29" rim meant for use with Surly's new Knard 29x3.0" tires. This configuration represents a new large-diameter fat bike bike standard created by Surly. Thinner spokes were used based on a lighter rider weight to provide additional comfort to the rigid bike. Check out more details on the wheels here.

Since a conventional 29'er frame doesn't have clearance for a 29x3.0" tire, Surly built a new model called Krampus. The Krampus frame set is similar in concept to their Karate Monkey 29'er - a value oriented chromoly steel frame and fork that can hold up to a lot of use and abuse. Like the Karate Monkey, the Krampus frame has horizontal dropouts with a derailleur hanger, so it can easily be set up with an internal gear hub, single speed, or with derailleurs. Along with the additional tire clearance, the Krampus frame gets a more trail-bike oriented geometry with a more relaxed head tube angle and higher bottom bracket compared to the standard cross country numbers of the Karate Monkey. A 44mm headtube also comes standard, which will allow the use of a tapered-steerer fork should any become available in the future. As a bonus, the Krampus frame and fork get sparkly green paint!

Setting up the Rohloff SPEEDHUB 500/14 on most Surly frames is pretty straightforward. The Krampus frame doesn't have any Rohloff-specific features like the Big Dummy, Ogre, Troll, or Disc Trucker, but with the use of our Monkey Bone, you still end up with a clean setup. A threaded axle hub is used to position the wheel/tighten the chain easily and the shift cables are zip-tied to the frame. The rest of the parts came together in a package that looks to be a blast to ride on the trails based on our short post-build test ride.

Build details