25 November 2013

Surly Krampus 29+ Commuting/Mountain Bike with Rohloff SPEEDHUB 500/14and Gates Belt Drive

Surly Krampus with belt drive and a Rohloff.
It’s not often that we’re asked to build the ideal bike for someone commuting in Siberia. We dreamed up this build for a customer of ours who is a British expatriate working in the snowy climate of central Russia. He intends to do a mix of snow, dirt, and paved riding in sub-freezing temperatures and wanted a dependable bike that could handle a range of conditions but still feel speedy. He ruled out a full fat bike and opted for the more versatile “29+” platform, a tire/rim designation that Surly invented to provide the float and traction of a fatbike, but the fast rollover of a 29er mountain bike. Once we agreed on the type of bike, we set to work planning out the build specifications.


Rohloff SPEEDHUB 500/14, belt drive splitter,
and Gates Carbon Drive belt system



Surly’s Krampus is the bike that brought the 29+ platform into the world, and is still one of the few bikes designed specifically to use 29x3 inch tires on 50 mm wide rims. The Krampus frame is optimized for speedy trail riding, but since its debut, it has also gained a reputation for being a comfortable off road touring bike. Our customer’s riding style is a perfect mix of these two disciplines: a stable, touring-style setup to deal with snowy or sloppy conditions and also a nimble-handling geometry that will roll fast and get him where he needs to go quickly. We sent this Krampus frame off to a framebuilder to get a belt drive splitter installed and also had the frame powdercoated black to fulfill our customer’s desire for a stealth-looking all-black bike.

For the wheel builds, we used Surly’s 29 inch diameter, 50mm wide Rabbit Hole rims, which spread out the tire to provide ample contact with the ground. We laced the rims to a Schmidt SON28 dynamo hub in the front and a Rohloff SPEEDHUB 500/14 in the rear.

The SPEEDHUB works exceptionally well in icy, sub-freezing conditions. Traditional derailleur systems use cassette cogs that can get caked with snow and then freeze over when the temperature drops, preventing the chain from being able to move into different gears. On top of the cassette issues, pivot points on the derailleur itself can also ice over, immobilizing the shift system. Lastly, the chain can freeze, creating stiff or stuck links. Icy conditions can prevent shifting, or worse, prevent the cranks from turning, completely incapacitating the bike.

Because the SPEEDHUB employs a shift system that is housed entirely within the hubshell, it is protected from getting clogged with snow or ice. The gears in the hub also sit in a sealed oil bath, and use a fluid that resists freezing. The inability to freeze is also true of the belt drive: unlike a chain, the belt is made of one continuous loop instead of a collection of moving parts, meaning there are no links or connections to get frozen.

Our customer said he would be riding through variable conditions and did not know what he would encounter on his un-maintained roads and paths each day. To ensure a comfortable ride for day in, day out commuting, we outfitted him with a Jeff Jones H-Bar, which has plenty of backsweep and multiple hand positions. We also used Ergon’s GP1 ergonomic grips, with a sizable palm rest to keep his hands and wrists from getting numb. A Brook’s Flyer saddle, which uses dual springs under the seating area, provides a comfortable platform able to absorb any bumpy roads. Finally, the Knard tires ensure plenty of cushioning and shock absorption when run at lower pressures.

Jeff Jones H-Bend handlebars, Salsa Minimalist rack,
and Supernova E3 Pro front light.

We also installed a few add-ons that would help the bike fit our customer's unique needs. We put on Salsa’s Minimalist front rack so that he could carry his gear to and from work. We then bolted a Supernova E3 front light to the rack and fitted an E3 rear tail light to the seatpost. The lighting system was connected to the front generator hub, giving our customer as much battery-free lighting as he needs during the long Russian winter nights.

When the bike was complete and we test rode it, it felt very capable and versatile. The large diameter wheels quickly picked up and kept momentum, giving us the feeling we could keep rolling with minimal effort. Our customer is looking forward to getting plenty of riding time in on the bike, and expressed his pleasure with how it came together. If you’re looking to build up a bike for icy conditions, give us a call!

Build Details:

• Frame: Surly Krampus customized with belt drive splitter and black powdercoat
• Fork: Surly Krampus with eyelets
• Headset: Hope ZS44 inset
• Stem: Thomson Elite x4
• Handlebar: Jeff Jones H-Bar
• Shifter: Rohloff
• Grips: Ergon GP1
• Seatpost: Thomson Elite Layback
• Saddle: Brooks Flyer
• Seat Clamp: Surly
• Front Hub: Schmidt SON 28
• Rear hub: Rohloff SPEEDHUB 500/14
• Spokes: Sapim Force
• Nipples: Sapim Brass
• Rims: Surly Rabbit Hole
• Tires: Surly Knard 29x3”
• Cranks: RaceFace Turbine
• Pedals: Shimano PD-A530
• Bottom Bracket: RaceFace
• Chainring: Gates Carbon Drive
• Rear Sprocket: Gates Carbon Drive
• Chain: Gates Carbon Drive
• Brakes & Levers: Avid BB7 MTN
• Rotors: Magura Storm
• Extra: Salsa Minimalist front rack, Supernova E3 Pro 2 front light, Superrnova E3 tail light

4 comments:

  1. Replies
    1. Shoot us an email (info@cyclemonkey.com), and we'll put an estimate together for you. We build bikes to order, so you can request different parts or we can build an exact replica (minus the discontinued Salsa rack).

      Delete
  2. I think you left out one spacer for the stem.?

    ReplyDelete
  3. I see that you opted for crossover lacing in the front wheel, which indeed seems a good choice having the Son28 very narrow flanges and rabbit hole very large offset holes. Any special advice on crossover lacing with Rabbit holes and Son28? thank you!
    Rob.

    ReplyDelete