Staying on top of the Gear


by Byron on Sep 02, 2006 at 5:27 PM

Todd, the inventor of the Stokemonkey says, “Your timely and appropriate shifting permits the motor to operate within a small band of powerful and efficient speeds at all times. This is key.”

As a roadie, I was reminded of that saying, “stay on top of the gear” and found Bettie’s sweet spot within a few minutes of riding. When the Stokemonkey bogged down a bit, I’d shift, and the motor assist would pick up speed again. After a few longer rides, I could tell how well the Stokemonkey was operating by the vibrations in the seat tube and also hear it cranking away. In the video, I’m rolling up a gently sloped, 5% grade hill.

The “small power band” also keeps you working. This isn’t an electric or gas-powered bike, it’s an assist and going up the steepest hills, I was definitely pedaling at a good effort (not breaking a sweat and breathing hard). On the last ride, I took my Polar and averaged a heart rate like a typical cruising pace, which is a great winter heart rate and a good workout.

So what we have now with Bettie and this project is a great errand/working bike. I used it to get lunch and say hello to Marcus while he brews up Bike Hugger Brown. Later in the day, Pam got a full load of groceries and we didn’t burn an ounce of gas or start the car, and got a nice workout. As Todd warns, a Stokemonkey isn’t for someone that isn’t in shape or isn’t good at riding a bike and shifting. In fact you could probably start a Tuesday night Stokemonkey workout club!

Next week, after the holiday, Pam will commute on it and I’ll post on all the details including the parts we chose, why issues, recommendations, and a wish list.

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nice clip! everything you say is true, but it sounds at least faintly like you’re underwhelmed by the power. part of this is because you’re in low-power mode (i hope) while conditioning your battery, but another part of me fears that your very first rides were too hard on the unconditioned, not-fully-charged pack, and… you see where i’m going.

i’m going to send you my very last DrainBrain (diagnostic loaner for support purposes) to help get some numbers on your performance, to see if it’s normal or not. low mode and an unconditioned pack should feel only 15-25% less powerful than what you rode here at cleverchimp pan-galactic HQ. if it’s worse than that, something’s wrong.

i remember my first riding impressions of the earliest prototypes still experientially relevant to the present product. they felt, well, like bike rides! over time, though, i learned to tweak stokemonkey (gearing changes, modes) and my own habits (cadence/shifting) to support a broad range of experiences between “workout” and “easy spinning,” depending on what i wanted, how i was dressed, the weather, etc.

at my nearest lbs in san francisco, pedal revolution, they had an old stationary exercise bike on the floor as a prop. it was like from the 1920s or earlier. and it was kind of a joke, because it had a power switch for a motor that drove the pedals. you just sat there and got pedaled. the design is less ridiculous than you might think, though, because it is unpleasant to let yourself be pedaled. inevitably it forces at least light aerobic exercise as you lead the motor, elevating the heart rate and making you want to work. stokemonkey will always give you at least a light aerobic workout, but it’s up to you how much further to take it. i hope to have succeeded in designing a system that doesn’t get in the way of hard riding, even as it makes it unnecessary as long as the charge lasts.

Thanks Todd for the response here and in the galleries. Very helpful and appreciated. We are definitely in low-power mode and on a full, overnight charge. The power does feel less that my experience at the place with the incredible gate and I’m happy to run the diagnostics and test it all out. It should also be noted that we live in a very hill area of Seattle, 12 - 18% - 22% grades and I’ve been riding up all of those — Pam took 150 pounds of kids up an 8% grade. Besides the testing, to see what the monkey can do, that’s real world for errands and riding around the ‘hood.

I think we spent about a hour total on it without a full charge, add a 1/2 hour to include everyone in the shop taking it up the nearest steep hill they could find.


Today, on a flat bike path, I was rolling right along, I’d say at about 20 mph. Regarding succeeding in “designing a system that doesn’t get in the way of hard riding, even as it makes it unnecessary as long as the charge lasts.” I think the Bettie’s weight is getting in the way of a good ride. Without power, on the flats, Bettie doesn’t just roll and that’s because it weighs a ton, has those monsters tires and the disc brake is rubbing. I don’t know how much resistance that disc brake misalignment is causing, but it does not feel as agile as your Super Monkey


Pam said it best, “you have to put it into a harder gear than normal up a hill to feel the power.” With only so much assist, that’s what we’re experiencing. I’m at about 1/2 the cadence I normally pedal up hill. As a bike racer, I’m always working on spinning and we may just need to get used to that. A few questions for you

  <li>How long should it take to charge</li>
  <li>How long do you think the charge should last, weighted and climbing</li>
  <li>When should we turn on high-power mode and “go for it?”</li>


about the disc rubbing, i’ve had the issue with 2 freerads, including the latest. in one case some dremeling fixed it, and some little washers did in the last. kind of a bummer, but as a newbie to the manufacturing business, i’m in no position to be harsh on such issues.

about being a good ride, in pure bike terms i get it. i ride a riv road among other bikes — i put more miles these days on light simple bikes than assisted haulers, barely. but i’ve also ridden my tank Xtravois 40 miles with no assist and kept pace with a guy on a 20-lb bike who’d just finished a tour of several hundred miles. i meant my comment more in the context of regular xtracycles [sic] and most other assisted rigs.

an easy 20mph flat is about what i’d expect in low mode, normal. high mode should make cruising in the upper 20s pretty easy [if your high gearing supports these possibly illegal assisted speeds].

pam’s right on about the paradox of upshifting into a hill to get stokemonkey working hardest. low mode was not meant just for conditioning batteries; it’s also the natural choice for “mashers” or those wanting max range (=less assistance). see “is there a learning curve” - . assist level is all relative to your cadence: more at lower pedal speeds (above a certain minimum). high mode pushes a high level of assistance into much higher pedal speeds. your spinner instincts will appreciate it. if you want max assistance at pedal speeds above 90 or so, you can get that by putting a larger freewheel on stokemonkey, but watch out: your run time per charge will go way down if you don’t compensate by a light touch on the throttle, and you should probably get the big battery if you want to do this on a default basis.

the small pack should take up to 6 hours to charge depending on how dead. you want to wait for the green light, pretty much every time if you can.

how long a charge should last is hard to state in layman’s terms. how heavy, how steep, how fast, etc? the small pack should give you 30-40 minutes of strong full-throttle time, whether you spread that out gently over a 50 mile ride or burn it up in one long heavily loaded climb. the technical answer is that it’s good for 324 or so watt hours, doled out over an s-shaped discharge curve (strong start dropping about 10% through to reasonably flat plateau, then diving the last 10-15%).

after 3-5 pretty complete charge/discharge cycles you should be fine trying high mode. but right now if your charger light is green, if you want, try it briefly, like a minute or two and see if you notice a big diff. if it doesn’t feel a lot more like what you experienced here, your pack is definitely suspect.