dual chain - has it been done?
 

has anyone ever made a dual chain bike? one chain on each side (although 2 chains on 1 side be cool, it wouldn't be nearly as cool as a chain on each side). since i have seen people do left side drive, i imagine it wouldn't be tough to make a dual side drive. i'm sure it would get you some funny looks.

this post has been done.

search for left-hand drive or something. there's a picture in there of just such a thing as you describe

yup, it's been done

there's a Schwinn on the FGG. I belive he did it with freewheels on both sides though.

ahh, finally found it:

http://www.fixedgeargallery.com/2005...eBikeCo-op.htm

and it is fixed, but with 2 freewheels.

Though not sure why anyone would want to add the weight of two cranks and chains to that frame. I have the exact same schwinn and if I could still pedal it with no crank/chain I'd do it just to cut another half pound off of the old 1020 steel bike.

To the original poster - interesting idea - and as the link shows, is possible. The cool factor is certainly there, but just got to wonder why. The only thing I could think of is the reduction on the forces pulling on the bottom backet and rear hub from the offset chain from the centerline.

pretty much just the weird-factor. a real hardcore idea:

paint the sides of the frame different colors, and get those colored cranks and chains on the oposite sides.

I will do this someday, and the result will be arguably pointless but undeniably sweet. If you did it with a Level rear hub, you wouldn't have to worry about any cog alignment issues (symmetrical cog positions) like you would with a threaded track hub.

All the while, wearing this!

There is another possible reason to do this, and it is not pointless.

I don't know if this was already "done" in the other thread - my apologies in advance if it was.

Years ago some track racers tried to build a better mousetrap for the 1km time trial. In this event the athlete must start from a stopped position on the track, accelerate to top speed, and the time is taken at 1km. Lowest time wins. Gear selection is everything - a bigger gear means higher top speed, but slower acceleration. A smaller gear means faster acceleration, but a lower top speed...

Anyway, some guys (if anyone knows who please tell me) built their bikes with two fixed gears, one on each side of the bike. The right side had a low gear for fast initial acceleration. On the left side was a much bigger gear, but the cog on the hub was unscrewed almost all the way. This was legal because there is no freewheel, just two fixed gears.

When the rider starts pedaling, he's using the small gear. The big gear on the left, which has more leverage, starts threading its rear cog on. When it tightens, the big gear takes over, and the small gear is just along for the ride. So, you get a low gear for the start, and a bigger gear for cruising. You could get four or five turns of the smaller gear before the big one took over.

Of course, it only works once, which is fine for a drag-race type of application, but it would be foolish for riding on the street. Every time you decelerate, the big gear would start to unwind...

i don't get it. a smaller chainring on one side you're saying and a bigger one on the other? how can the larger chainring "take over" when the smaller one has no way of disengaging? as soon as the cog screwed all the way up the whole thing would lock up, no?

Yes, you're right. The smaller gear has to disengage. It must have been set up to unscrew (no lockring). But it would unscrew a lot quicker...

I wish I could find where I read about this. In the end, the guys figured out that the two gears needed to be very close in size, and that the friction of two drivetrains and all that screwing was slowing them down. Also there was a big plastic chain guide on the right seat stay that rubbed the chain. Not a speedy setup.

i propose an "illigal questions" sticky... this is the first..

Yeah, that's really intriguing...

yea ok, but then i guess it would fall off, chain into spoke, death, etc etc.

yea sounds complicated. interesting experiment though. imagine that the resistance of the first cog "unlocking" would be pretty rough too

Can someone post the picture of the green dual-drive fixie with the weird, 24" fat-tire wheel up front? I want to say it was from a Dutch messenger event....?

Not the one I was thinking of, but I found this here: http://www.bc-hellsinki.com

Here's a little gearing/chainline action if you're looking for some... http://www.morcmtb.org/photopost/dat...60-gearing.jpg

thats just wicked

That's insane. And, even more so, it looks like there are teeth of cogs poking up between the cogs that are engaged in the chain. Ridiculous.

yeah, and the outside chain has more slack than the other two?

And what kinda rim is that???