Sunday, December 07, 2008

Retro-Direction Perfection?

I never quite know how my various bicycle projects will turn out. Once I'd gotten my retro-direct bicycle past it's initial proof-of-concept phase and into something I'd actually trust for my commute, I hit up against another problem. While the bike worked fine in a mechanical sense, my body didn't seem to like pedaling backwards to climb a hill. When I'd climb out of the saddle, I'd tend to slip into forwards pedaling and the leverage just seemed wrong. I gave myself a few days to adjust, telling myself that I'd spent years pedaling forwards and I tried different front chain rings in an attempt to get the low gear lower.

But the real problem was the bike didn't seem practical. It seemed always geared wrong and while the bike had a fun novelty about it, it really didn't feel like something I'd enjoy riding every day. I was pretty close to writing the bike off as "a good learning experience" when Jacob Slosberg stopped by the shop. Jacob is a former earn-a-bike student who also worked in the Bike Works shop a year or so ago. After hearing my problems with low-gear backwards pedaling, Jacob made this brilliant and simple suggestion:

"Swap the chain around. Make the backpedaling gear the higher one and the forward gear the lower ratio."

Brilliant, simple and the thought had really never occurred to me. Sure that Zoobomb guy had his bike geared as low forward, high backward but the Wikipedia article and most other articles I'd read describe having the lower gear be the one engaged by backpedaling so that's the way I'd set up my bike.

Oh well, it'd be easy to test. I rerouted the chain and went for a ride.

Not since Doc Brown installed a flux capacitor in his old DeLorean has a single hardware change had such a dramatic effect.

The bike went from being interesting to being wonderful. Instead of awkwardly thinking at a light "I'm starting from a dead stop, I'll have to pedal backward", I'd stomp the pedals in a normal, natural manner. As the bike picks up speed and I'd start to think "I wish I had a higher gear" and I'd recall that I do have a higher gear at my disposal. Engaging that gear by pedaling backwards is much easier and automatic when done in a moment of ease instead of a moment of stress. When the terrain resembles that Irish blessing and rises up to meet me, I pedal backwards until the effort seems wrong. And then, effortlessly, I switch to forward pedaling, engaging the lower gear. If the road steepens further, I rise out of the saddle. When I crest the hill, I settle into the saddle and backpedal down the backside. It doesn't feel odd, it feels natural. Those poor saps with their mono-direct bikes, they don't know what they're missing!

The first test ride was only 18 miles but within the first couple of miles I was sold on retro-direct, low-normal, high-reverse gearing. It suddenly made perfect sense, like back in high school when I learned to work an HP calculator. RPN and Forth programming expanded my young nerd mind three decades ago and now an old bike with an oddly routed chain has opened up a similarly expanded route through this wonderful world.

I did tweak one thing on the RetroTrek after that epiphany ride. I swapped the chainring out for something bigger. The RetroTrek now sports a 42 tooth front ring. With the 16 and 22 tooth freewheels, I have a low forward pedaling gear of 49.6 gear inches and a high reverse pedaling gear of 68.25 gear inches. My experience riding fixed gears had lead me to choose about a 70 inch gear for road, while my Monocog mountain biking had shown me a gear around 49 inches is right for me for that application. And now, those two gears (or at least very close approximations) are contained in a single bike. A bike that I pedal backwards sometimes.

A week ago I wrote: "I'm not going to try to convince you that a retro-direct drive bicycle is practical." I was wrong about that. I guess I am trying to convince you. Because I've convinced myself. No, scratch that, the bike's convinced me. Backwards is the new forwards. You heard it here first.

Keep 'em rolling,


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