Bettie 2.5: Bringing the Monkey Back10
by Byron on Sep 16, 2008 at 9:01 AM
We just updated Bettie to 2.5 with the addition of the Stokemonkey – we did it with a one-time exclusive, Rolling Jackass mount and barrel-adjustable tensioner. Bettie 1.0 was stoked and when we built Bettie 2.0, we already had 2.5 planned. Our decision to make a Monkeymount was driven by back-to-school and getting the kids to and from schools. For those wondering, Stokemonkey status is best found on Clevercycle’s blog. At this time, according to the blog, they are not back on the market. We recommend Stokemonkey owners wait to hear from Clevercycles on the status of Big Dummy mounts and Stokemonkey retrofit kits.
I’ve written extensively about the Stokemonkey and Human Electric Hybrid Drive when we built Bettie 1.0. With 2.5, a Stokemonkey Nuvinci drivetrain is a pleasure to ride. It’s like a smooth, automatic transmission on a car. You’re applying power to a continuously variable planetary hub. That means there’s no gears and it’s quiet, almost effortless and efficient. It does take some skill – nudge the Nuvinci with power off, then back on and do it simultaneously to not jerk around
You’ve got to unthink how you shift now when riding Nuvinci and learn all over again. The twist-shift visual indicator is a good analogy. It looks like an inchworm and that’s how you should think about shifting. Instead of gears, it’s minor adjustments. You nudge it either easier or harder and maintain a continuous cadence.
That continuous cadence is key; especially with power on. Bettie 2.5 is equipped with a Rolling Jackass Custom chain tensioner so that dual chainrings can be used with the NuVinci hub. The small ring gets us up 17% grades and the Nuvinci, under load, requires you to pedal in circles. If you don’t, it’ll kick back against the chain. That’s magnified with the Stokemonkey and for the hills, I’ll stop applying pressure to the pedals from my legs and let the Stokemonkey and Nuvinci do their thing.
Here’s video of the drivetrain in action.
When Val fired the Bettie up, I said, "Electric MonkeyLove."
Damn it’s cool. And this morning, I took Kid 2 to school, up the big hills with power to spare. Next up is Kid 1 who HATES that I take her to school on a bike; especially when I honk the airhorn repeatedly and wear my euro gear.