Make your Xtracycle or Big Dummy a real car-replacement vehicle. Designed specifically for the Xtracycle and Big Dummy, the Stokemonkey drives your crank rather than your wheel. This allows it to take advantage of your bike's gearing for those really tough hills.

Stokemonkey is an electric motor assist kit for cargo bikes built to Xtracycle's open source longtail standard. Xtracycle's hitchless trailer concept gives bikes amazing cargo capacity, and Stokemonkey gives you the power to haul it over mountains or swiftly across town.

Designed in a car-free household by Clever Chimp, the Stokemonkey was specifically made for people who want to replace their car trips with a bike. It can tackle moving and transport jobs that even the most dedicated riders would hesitate to do unassisted. This company is also one of the most safety and quality-conscious ones we work with.

Here are a few of the things you can do with a Stokemonkey:

• Transport a spouse, a child (or two), and your camping gear dozens of hilly miles offroad and back
• Pick up a friend with two checked bags at the airport.
• Save your knees from pre-mature abuse
• Ride thousands of vertical feet between your farmers’ market and your family kitchen without qualifying for charitable sponsorship.
• Commute twenty-five miles each way, even if you can’t shower at the office, and especially if you never want to sit in traffic.

How it works

With the Stokemonkey, your bike rides like it does unassisted most of the time. But when you want help, you turn a variable throttle on the handlebars to activate the motor. The motor drives the pedals, just like the stoker of a tandem bicycle helps the captain. You cannot use the motor without pedaling, but you can pedal normally without any motor resistance, and coast whenever you let go of the throttle.

The motor used is essentially the same type as a hub motor, but instead of driving the wheel, it drives the pedals. All motors have a peak efficiency range, and with the stokemonkey, as you shift gears to maintain your normal pedal speeds, you keep the motor operating in this powerful and efficient range. This uses overall less energy than motors operating at variable speeds, resulting in longer range for the same battery. In addition, when climbing a steeper hill, or under heavy load, the motor will provide more torque and better speed than an equivalent hub motor.

A backlit handlebar-mounted display provides system status, including power usage, battery state, efficiency, and typical cyclocomputer functions, in addition to programmable parameters like maximum power and motor speed.

Stokemonkey uses a direct-drive, brushless motor with no internal moving parts other than sealed bearings, for maintenance-free, cool running, virtually silent operation. All drivetrain parts subject to wear are standard bicycle components that can be replaced easily after decades of service.

Stokemonkey is designed specifically for the Xtracycle or Big Dummy. It has been adapted to the Radish, and V1 Yuba Mundo. It is not compatible with non-longtail bikes (if you have one of these, check out some of our many other options).

Performance

Stokemonkey really shines under heavy loads and on steep hills. It can accelerate these loads quickly, so you aren't slow through an intersection or stranded after a stop on an uphill grade. It's been tested on some of the steepest hills in the nation - San Francisco - where it managed to haul 480 pounds gross up a 31% grade. With this kit, you can be confident that you will be able to move any reasonable load up virtually any hill you encounter.

Stokemonkey can sustain 500watts of power up and down hills and on the flats. (This is equivalent to what a pro bike racer can output.) It's top speed is 20mph (conforms to the US federal Consumer Product Safety Commission rules) and it can maintain this speed even on moderate hills. It is powered by a 36V battery - sold separately to match your range requirements and your budget. Many batteries can be easily slipped into the inner pocket of the free-radical bag, leaving space for your cargo and providing an out-of-sight mounting option.

The Stokemonkey comes with everything you need to electrify your Xtracycle or Big Dummy, except the battery (see battery section for options).

Red Crystalyte direct-drive, brushless motor, 500w nominal - equipped with a freewheel
• 36V 20A controller with on/off switch, and "burrito bag" for easy and waterproof mounting to your frame
• Includes chain loop, pinch guard, and bracket with stabilizer cable assembly
• Cycle Analyst, specially modified for Stokemonkey compatibility
• Clampset to attach to your frame (specify for Xtracycle or Big Dummy)
• Left thumb throttle (or specify right twist throttle)
• RIght and Left chainring set for square-taper bottom brackets, 170mm arms. Specify :
• Compact MTB (Sugino Mighty) single or triple right side chainring (best for most Xtracycle mountain bike conversions) OR
• Compact road (Sugino XD) triple right side chainring (best for Surly Big Dummy)

The basic kit doesn't include a battery. You can select one of our 36V battery options to complete your electrification project. Any 36V battery will work with the kit. Your range will be determined by the size (amp hours) of the battery you choose.

Stokemonkey is covered under our Ride Your Bike More guarantee. If at any time in the first 3 months you are unhappy with this product, you can return it for a refund (we only ask that the product is is good condition upon return). Stokemonkey is also warranted for 2 years against defects in materials or workmanship