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Cycle Monkey

Internal Gearing Specialists, Bicycle Distribution & Service Center

Rohloff-Equipped, Motorized Surly Big Dummy Cargo Bike

This custom painted Surly Big Dummy hybrid was done for a customer in San Francisco, CA who was looking for an alternative to using his car for day to day activities. The Big Dummy offered the cargo space that he needed and the Rohloff SPEEDHUB 500/14 offered wide gear range and a maintenance-free drivetrain, but getting up and over the steep hills in San Francisco was a challenge, especially with heavy loads. The Stoke Monkey electric assist motor from Clever Cycles offered the extra boost that was needed to make car-free errands a reality.For the wheels on this bike, we laced up the Rohloff rear hub and a Phil Wood front disc hub into Alex DX32 rims using Sapim Race double butted spokes and brass nipples. The DX32 rim is very wide at 39.1mm but relatively shallow at 15.7mm. This is one of our favorite rims for cargo bikes as the wide profile opens the tire up to spread the load better and the thick spoke bed and sidewalls provide the strength and durability to handle heavy loads.Clever Cycles designed the Stoke Monkey specifically for use with Xtracycle-based longtails. The unit clamps onto the frame without the need for any frame modifications. Attachment brackets are available for the Xtracycle FreeRadical long tail conversion kit or the Surly Big Dummy frame, with its integrated long tail. The motor is not intended to be a replacement for human power but instead provides assistance comparable to a strong rider. There is a thumb-controlled throttle on the handlebar and a digital readout shows your speed and battery life. Since the motor output is run through the drivetrain, the battery life is maximized. As the gears are changed to give you the most appropriate gear to pedal and the best pedaling efficiency, the motor works more efficiently and consumes the battery charge more slowly. The high efficiency of the Rohloff SPEEDHUB 500/14 also contributes to a long battery life.The Surly Big Dummy has proved to be a popular frame for adding a Rohloff SPEEDHUB 500/14. The durability of the SPEEDHUB 500/14 is well proven and is a sought after item for building a reliable commuter bike. One of the main challenges that people confront when trying to use a bike instead of a car is how to carry stuff. Things like spare clothes, laptops, lunch, groceries, boxes to be mailed, etc. that are easy to toss into a car can be difficult to transport on a bike. The Big Dummy frame offers a viable solution for carrying a wide variety of items in the long cargo bags, attached to the wooden platform, or strapped to various Xtracycle accessories that plug into the frame. Many people think of the Big Dummy as the bike equivalent of a pickup truck.Build details

  • Frame: Surly Big Dummy
  • Fork: Surly Big Dummy
  • Headset: Chris King No Threadset
  • Stem: Thomson Elite
  • Handlebar: Nitto Northroad
  • Grips: Cork
  • Shifter: Rohloff
  • Seatpost: Thomson Elite
  • Saddle: Brooks B17
  • Front Hub: Phil Wood Front Disc Hub
  • Rear hub: Rohloff SPEEDHUB 500/14
  • Skewers: Shimano XT
  • Spokes: Sapim Race
  • Nipples: Sapim Brass
  • Rims: Alex DX32
  • Tires: Schwalbe Marathon XR
  • Cranks: Sugino Tandem
  • Bottom Bracket: Phil Wood Stainless
  • Chain Tensioner: Rohloff
  • Brakes: Magura Louise
  • Rotors: Magura Louise Wavy
  • Fenders: SKS P65
  • Motor Assist: Clever Cycles Stoke Monkey