Rohloff on Surly Krampus

I purchased a Moonlit Swamp Surly Krampus frame in 2014 with the intention of building a wonderfully utilitarian mountain bike for long cross-country rides and moderate duration bikepacking excursions. In the four years the Krampus has been a part of my life, it has been utilized as originally envisioned, for awhile as a robust single-speed commuter during a failed two year attempt at polyamory involving a Salsa El Mariachi, and most recently as a dynamic yet fully rigid road touring bicycle as it confidently carried me and some gear across the United States. Though it is an indoor bike, i.e. garage/bedroom kept, it has handled with ease the worst the outdoors has to offer, including a high-speed impact with a large pine tree, from which I was fortunate to walk away relatively unscathed, a couple minor over-the-handlebar incidents, and a few harsh Montana winters.

From the outset of the build process reliability was a primary consideration, so it was natural to include the Rohloff Speedhub 500/14. The Rohloff itself comes with a long list of pros and cons from other people who have tried it. Pros like no derailleur to bend/break/adjust, nothing to clog with mud, equally spaced gearing, simple shifter, large flange diameter to provide a stronger wheel, non-dished wheel, increased chain longevity from good chain line, perception of tremendous manliness by uninitiated observers assuming you are crushing it on a single-speed. Cons like substantial weight, inefficiency, or perception thereof, oil weep, cost, and noise. This is a short summary of my personal experience with the Rohloff on a first-generation Surly Krampus.

The Krampus in a hybrid mountain commuter configuration replete with cup holder, navigation system, and prayer flags.

The Krampus frame features horizontal, rear-facing fork ends and a derailleur hanger to accommodate both bolt-on and quick-release hubs, and disc brake mounts. The Rohloff hub requires use of a torque arm attached to the non-drive side of the the axle to prevent its rotation in the frame when torque is applied to the drive side through the chain and pedals. There are several torque arm options including a standard torque arm, and a variety of axle plate/brake adapter combinations. There is plenty of information available elsewhere to describe these installations, but there are particulars of the Krampus geometry that complicate utilization of at least two of them: the OEM axle plate in the fork end, and the OEM2 axle plate used with the Monkey Bone.

The OEM axle plate has a small rectangular protrusion that is designed to fit into a slot in certain Rohloff-specific frames, such as any number of Rohloff Swing Plate equipped Salsa models. This protrusion is conveniently slightly narrower than the horizontal fork end, so there is a temptation to go for a very clean installation by affixing the OEM axle plate to the hub and sliding its tab into the fork end. Unfortunately, the fork end is not designed to withstand the applied torque, and, consequently, it is opened up with relative ease when pedaling in low gears. I learned this lesson the hard way on a shakedown ride shortly before embarking on a long tour.

The rear-facing horizontal fork end of the Surly Krampus is no match for the torque of the Rohloff hub. The OEM axle plate in the fork end is not a Surly-sanctioned solution, and this is why.

The reason I was tempted to try the OEM plate in the fork end in the first place was because of a different problem with the OEM2 and Monkey Bone configuration. On the Krampus there is not sufficient vertical distance between the axle and the slots in the Monkey Bone to allow the axle plate to rotate out of position. As the axle plate rotates, it contacts the Monkey Bone. To continue rotating, the axle must be allowed to move away from the Monkey Bone, but it is unable to do so as the axle is driven into the bottom of the fork end. As the wheel is pulled rearward it becomes wedged and is impossible to remove from the frame. Rear wheel removal requires loosening of the disc brake adapter. It is not an insurmountable problem for mechanically proficient cyclists, but it is annoying to have to mess with brake hardware just to fix a flat tire. It complicates things. However, after bending the fork end on my frame and seeking to avoid the visually unappealing standard torque arm, difficulty of wheel removal was a compromise I begrudgingly accepted.

After the failed experiment with the OEM axle plate I needed to repair the bent fork end to properly secure the wheel in the frame. I opted to use the box end of a long combination wrench to gently guide the displaced fork end back to its original position. Before doing so, however, I realized that I had inadvertently resolved my wheel removal problem and that by not bending the fork end fully back into position, leaving it open by roughly a millimeter, there would be sufficient room for the axle to drop and the axle plate to rotate out of the Monkey Bone without having to loosen the brake caliper. How fortunate. The wheel still fits snugly in the foremost position in the fork end, but as it slides rearward the fork end drops away very slightly, allowing the axle plate to rotate and the wheel to be removed. Thanks to my inadequate foresight I stumbled upon a seemingly serviceable solution to my chief complaint pertaining to the use of a Rohloff with a Surly Krampus — the inability to remove the rear wheel without loosening the brake caliper.

The Krampus Dance.

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