Dennis:

I can't tell you how long I, and I think every other regular viewer of your page, have wished that I had a fixie worthy of posting on your site. It has been an inspiration.

Well, here it is. The only thing is, neither of its chains are actually fixed to the rear wheel.

This bike started out as a friend's concept, one that had clearly been tossed around before. I'm sure it wasn't a new idea, but it was new to me and I was amazed by it.

It's simple: run two drive cranks to a flip-flop hub with freewheels on both sides. The right-side freewheel will engage when pedaling forward, and the left-side freewheel will engage when pedaling backward. If you use a tandem stoker crankset, you'll be set. Of course, putting it together with nice chainlines and all could be hard, but I am lucky enough to have a non-profit full-service shop at my disposal, so I could be sure to piece something together.

The result, I think, is beautiful. I used a tandem crankset, two made-in-Taiwan freewheels, old QBP chainrings, and the cheapest of the cheapest J&B-built flip-flop wheels: a Suzue hub laced to a Weinmann rim. The rest was easy: random new front wheel, cheap Z-chains, a 1mm freewheel spacer, singlespeed chainring bolts, pedals w/ Powerstraps (NOT an especially effective product...), an old SR stem and some cruiser bars, flipped and chopped a bit. The frame came from the very friendly Bike Church (downtown Santa Cruz, CA), the saddle was a hand-me-down from my own grandfather, and the tires were donated, a few months ago, to the Bike Co-op (UCSC; where I work, and in whose name I built the bike).

And the thing is, everything worked out perfectly. The chains are parallel to within a few millimeters, and the entire drivetrain is almost dead straight. However, there *is* a strange sensation, feeling much like chain slop, which is due to the fact that the pawls on the two freewheels don't line up perfectly, and so engage at slightly different points in the pedal stroke. It's a bit weird, but no weirder (and much safer) than riding with a slightly loose chain - I'm sure a pricier freewheel could suck the problem up as well.

At first I thought I would hate the geometry on the bike, but then I took it on a 25-mile ride with some roadies and discovered that I loved it. Plus, it's handsome enough that many the average person on the street doesn't even realize that it has two chains.

It's definitely a gimmick, but it sure is fun. I've discovered a few things about the drivetrain model that I describe with (I think) reasonable accuracy, and with more pictures, at http://people.ucsc.edu/~snwright/mybikes/doublechain.html.

Again, thanks for the site. Spencer Nathan Wright bikecoop@gmail.com