Stokemonkey overview

Stokemonkey is Clever Cycles’ answer to the problem of steep hills and heavy loads. It’s 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.

Most electric bike products are designed for people who don’t, won’t, or can’t ride regular bicycles, even without passengers or cargo. Stokemonkey is different, designed for everyday bikers who will continue to ride on their own power most of the time, but want a more capable car alternative some of the time. We don’t believe in replacing human power with electricity; we believe in replacing cars for work that even the strongest cyclists seldom if ever choose to handle without a car. Developed in a car-free household, Stokemonkey is for fellow riders who want to become more completely independent of cars in their daily lives.
  • It’s for people who want to transport their spouses, children, and camping gear dozens of hilly miles offroad and back. It’s for picking up a friend with two checked bags at the airport. It’s for your knees. And if there are thousands of vertical feet between your farmers’ market and your family kitchen, now you can pedal those couple dozen melons home without qualifying for charitable sponsorship.
  • It’s for people who commute twenty-five miles each way, can’t shower at the office, and never want to sit in traffic.
  • It’s for people who understand that vehicles heavier than what they carry are inefficient almost by definition; that fiddling with their fuels comes at sustainability problems from the wrong end, and ignores the social and health problems of car dependence in built environments altogether.

How it works

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. As you shift gears to maintain normal pedal speeds, you keep the motor operating between its most powerful and efficient speeds, for several times the torque, higher top speeds, and much better range than typical electric bike products lacking variable motor gearing.

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 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 for decades of service. Stokemonkey is powered by non-proprietary 36-volt rechargeable batteries you carry like any other cargo.

In development since 2003, Stokemonkey is protected by US patent 7,261,175.

Performance

Stokemonkey’s exceptional torque moves heavy loads off the line quickly, helps you walk your grocery-laden bike up stairs, and enables you to haul adult passengers up the very steepest streets. We’ve managed 480 pounds gross up the steepest block in San Francisco (31.5% grade). This extreme torque capability distinguishes Stokemonkey from electric bike products not designed for cargo applications. Stokemonkey can sustain about 500 watts of assistance, which is comparable to the maximum sustained effort of a world-class bike racer. But Stokemonkey weighs a fraction of what the racer does, your power comes on top, and this full combined power can be applied even at walking speeds: think tugboat or tractor more than scooter.

Powered range is limited only by the amount of battery packs you carry. Experience suggests that your working range will be similar to what it is riding a light, unassisted bike, but that you will carry more, and arrive sooner with much less fatigue. Top assisted speed is limited electronically to 20 MPH to conform to US federal Consumer Product Safety Commission rules, but this speed can be maintained even up modest hills.

Stokemonkey adds 21 pounds to your Xtracycle before batteries, which start at about 10 additional pounds. Gross vehicular weights can start well below 70 pounds, not unlike many loaded touring bikes.

Cost

Stokemonkey costs about $1300 without a battery and charger. Generally, we don’t sell kit components separately, but you may omit parts for which acceptable substitutes exist. See the Order form for more complete information.

Stokemonkey usually pays for itself every few months when used to replace a typical car. More importantly, you get to ride a bike more often, even when you need to haul your family, groceries, or just your unbearably smug self further or faster than you would on a regular bike.

Guarantee & warranty

Stokemonkey comes with a six-week money-back guarantee, and a two-year warranty against defects in materials and workmanship. We advise you to purchase an Xtracycle, set it up, and become accustomed to it before ordering, so you will have the full guarantee period to install and evaluate Stokemonkey.

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5 Responses to “Stokemonkey overview”

  1. Bike Forth » Blog Archive » My Solar Bicycle Says:
    July 18th, 2010 at 08:51

    [...] type of cargo bike that has an extra long frame. And “stoked” means that my bike has a Stokemonkey electric motor that helps me out on the hills.) In general this summer I’ve been biking 10 to [...]

  2. Tools for Normalizing the Bike Commute | Commute by Bike Says:
    July 27th, 2010 at 17:43

    [...] to a longtail bike like the Surly Big Dummy setup with an electric kit like the Bionx system or the Stoke Monkey.  This would also have the normalizing effect in that I would always have plenty of capacity for [...]

  3. Bodo Linnhoff Says:
    August 16th, 2010 at 02:42

    I am impressed by this solution. I am also convinced that hubmotors are a bad choice for gradients and loads, the motor must be kept at optimum rpm’s.

    But there is one question I have: When I want to use the motor and have a respite from pedalling, I don’t like the thought that I have to keep moving my legs…. Would it not make sense to have a freewheeling mechanism for the front chainwheel, so I can either pedal, or use the motor, or do both?

    eLation in Australia even point out on their website that a driver could be catapulted off his bike accidentally without such a freewheeling mechanism.

    I am very interested in your system but appreciate your comment on this issue.

    Thank you.

    Bodo LInnhoff

  4. Todd (admin) Says:
    August 20th, 2010 at 08:51

    Hi Bodo – I believe I address your questions about freewheeling pedals in the FAQ, here: http://clevercycles.com/products/stokemonkey/faq/#waycow . In short I don’t consider this a problem whose solutions don’t introduce new, more troublesome problems. There’s more discussion here: http://www.flickr.com/photos/cleverchimp/3390730515/in/set-72157615918793181/

  5. More News from the Cargo Bike World | PHEW! – Philly Electric Wheels Says:
    September 2nd, 2010 at 09:54

    [...] interesting option is the StokeMonkey kit, which uses a motor that drives a second chainring on the cranks, much in the same way that a [...]

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