Big Dummy continued, and a digression on speed

Surly continues blogging about Big Dummy testing. We’re feeling thrilled and honored to have Stokemonkey hooked up to the one and only prototype so far, as evidently a test priority. Getting Stokemonkey some visibility and credibility among normal, avid, dare I say mainstream bicyclists and gear makers has been pretty much the only marketing plan I’ve had for Stokemonkey, and, well, it appears to be working.
Dave’s cooked up his own auxilliary threaded-rod-and-plate chain tensioner. Super secure, but I’ll be looking into ways to make do with less.


Dave cites the fun of going fast about five times. It’s true of course, and safer than going slow in some cases. But in a lot of places, it’s not street legal to get any help from the motor at speeds above 20 MPH without registering as a moped, which in turn implies things like turn signals and other DOT stuff generally remote from bicycle design priorities. Never mind that unassisted riders can exceed 20. Anyway, it’s a matter of time before Stokemonkey gets a speed hobble of some kind built in, as a means of reducing Cleverchimp’s liability exposure and that of potential distributors. Torque is Stokemonkey’s strongest suite anyway, as befits a cargo assist.

7 thoughts on “Big Dummy continued, and a digression on speed”

  • fred

    Thanks to Todd and Stokemonkey, I have an assisted Alligt Alleweder velomobile. The tensioning system shown above for this frame is very much like what I used on my velomobile. I don’t have any frame tubes on which to attach the very elegant and simple Stokemonkey tensioning cable, so it was long bolts passing through a square tube, braced on my nose bulkhead. Not quite the minimalistic cable, but still pretty simple.

    Regarding speed and restrictions, I am faster with my assist, of course, but if I remove the motor and batteries, I can still exceed 20 mph, safely, in my opinion.

  • Buddy Bonner


    Hook us up with some pictures of that Stoked velomobile….would love to see it…


  • Bill Manewal

    Yeah, they should tout its hill-climbing prowess and not just speed.

    Although I agree with the battery location (having purchased an experimental, uh… Woodie box from Todd), and while I know that Dave IS building a prototype , he is, in my opinion, doing both Surly and Cleverchimp a bit of disservice by posting photos of what can only be described as one fugly battery container, even if it IS for the Minnesota winters. If not a box, then maybe a larger ABS pipe and stuff the space with foam for insulation… anything but what looks like something stolen from an HVAC shop.

    Otherwise, great exposure.

  • fred

    budman, my construction project can be viewed at and there are links on those pages to a couple of Stokemonkey videos posted to YouTube. I haven’t linked all the YouTube videos, because I’m lazy when it comes to web page updates, but once you get one of them, the rest of them are listed under my username.

    Regarding speed vs climbing, I will add that having a Stokemonkey providing an assist has increased my climbing speed from 4 to 6 mph all the way up to 12 to 15 mph, depending on how much human bean is thrown into the system. I particularly like that I cannot loaf and have to pedal whenever the motor is operating. It tends to “keep me honest” in my contribution to the power levels.

    More than once, I’ve taken off from a parked stop, pedaled up through the first few gears and then noticed that the motor wasn’t drawing any current, because I’d forgotten to turn on the controller!

  • Brian Miller

    If you guys do add a speed inhibitor, please remember to tell us how to disable it!

  • adam cosic

    how about an eccentic bottom bracket to adjust the tension?

  • Todd

    adam, i have an eccentric BB on my custom longtail. it turns out not to be useful because over such a long chain run some frame flex is inevitable, and you don’t want that flex with a statically tensioned chain. also with a single-speed-style chainline, the lower chain run is too close to where the xtracycle’s front bridge needs to be; the chain thwacks it. so i use a rohloff chain tensioner.

Leave a Reply