The other day I was setting up a new fixie of mine and then got a crazy idea when I was looking at the conglomeration of parts which lay before me. I asked several people why this idea wouldn't work and I didn't get any answers which would stop me from performing this experiment, so please let me know your thoughts/experiences. What would prevent me from taking two right crank arms of the same length and make with identical chain rings on them and putting them on the left and right side of my bottom bracket spindle, (assuming I've got the right spindle length and have worked out clearance issues) and then running two chains to my double sided track hub with two identical cogs on either side, ( assuming I've got the rear spacing and chainlines all done correctly). The only problem my friend and I could come up with is the issue of having 2 right pedals and one of them possible dethreading, (not a big issue if I use loctite and get it in there really tightly). This idea seems perposterous like I would be stripping something or somehting would just plain not work right, but I cannot think of a single reason why it will not work. Imagine the driving force such a setup would have assuming that it works. It seems like such a set up would be very powerful. Has such a thing been tried before with success? Does anyone know why this won't work? Am I barking up the wrong tree or does this idea seem sound. Need help. thanks

Sounds kinda cool to me...do it!

Id be more worried about your rear cog unscrewing, if you use left side of the flip the cog is effectively backwards, so when you pedal forward you'd be unscrewing the cog!
I guess with some red loctite and a big ass chain whip you might be ok..

As well, I've heard you can drill out the pedal threads on teh left-hand crank and install a left-hand helicoil to get the proper pedal threading, though im not sure its worth it.

well the left side chain would pull the wrong way (from the threads' point of veiw) on the cog (wouldn't it?), which might not be a problem given a fixed/fixed hub and lockrings.... seems to me like any slight power increase might be negated by the added weight...

won't the cog on the left side be unscrewed by pedaling? or maybe the lockring threads will get stripped/mangled by the constant pressure from the cog.

and i can't imagine that the infinitesimal increase in power transfer (if there is any at all) would offset the increase in weight.

There was a big discussion on the Fixed Gear Mailing List about a year ago regarding this subject (dual drive fixies). Alas, you must be subscribed to the mailing list to view the archives, and I purposely unsubscribed to that list.
https://lists.davintech.ca/mailman/listinfo/fixed-gear

I think the main problem is that it's *really* hard to get everything perfectly aligned... something along the lines of tandems and timing chains? I'm sorta out of my league here, so I'll just post a picture instead. Note that the righthand side of the bike has a *gasp* DERAILLEUR... possibly for chain tension on a freewheel?

EDIT: that's actually a cassette on the righthand side, and it would appear to be a freewheel on the lefthand side. So I have no idea what the hell this picture is for

I'm not really worried about the little extra weight. if I did this obviously it would be on a fixed/fixed hub. I don't think it would strip because it's not like pedalling backwards will strip it, right? I am intrigued about experiencing the sensation of driving with a chainring in either side, (what if it is sweet?) Red loctite definitely will be involved if it happens. I would love to hear back about opinions about the stability of the two rear cogs and lockrings, if it is a track hub why would it be a problem?

I had a roomate from amsterdam who ran a double sided fix for kicks for awhile, He didnt like it or dislike it, favor it or not favor it, I'd tell you more of what he thought but his english stank and my dutch smelled much worse

it seems to me that if running double-sided was all that and a bag of chips that a lot more people would be doing it.

i think you should give it a shot, it's not like you have anything to lose, right?

moron

I really don't think it will give you any additional power transfer, because all the force (well, disregarding flex, which also takes place on the drive side) from your non-drive side pedaling is transferred to the exact same place as the force from your drive-side pedaling because the crankarms are rigidly attached to eachother. I'd imagine that by doing this, you'd only be adding complexity, weight, and a little bit more drivetrain friction.

I think you can make it work, but setting it up to get the chains to run smooth and getting the wheel straight may be a lot of trouble. Changing a tire will be more work. The bike will be heavier. There will be more friction. The single chain transfers the power well to start with. The power we humans put out is handled by one chain nicely.
The cog running the wrong way may come loose. Depending on the frame you may have clearance problems on the left side chainring to frame clearance. I don't see any mechanical benefit.
But, it will look cool, and everyone will ask about it! So try it and post pictures!

the only thing i see that wont work, that wasnt already pointed out(i dont think it was anyway) is the difference in wear on things, like if your using old chainrings, cogs, and or chains, then i think you could have a big problem. but if everything is new you probably wont. if that doesn't make sense, then sorry.

If you want to really throw people off, run a fixed cog on the left side and run a noticably larger freecog on the right side. The freecog side will always be ratcheting. I always thought of doing this myself but never got around to it.

Put a Campy crank on one side,with a Shimano on the other side. Paint one side of the bike one color and the other side another color.

The left cog couldn't unscrew because the right side would not let it. As you pedal forward I think the cog on the right would handle all the tourque. On back pedaling or skiding the torque would be on the left cog. Hmmmm.....


Tony

whenever i do this ill put up a picture, the necessity is the possession of two identical spiders and cogs

a company called clemtwin made this setup with a freewheel hub back in the early 80's. the idea is mostly a novelty which was left in the dust. you could run profile bmx cranks and use their left hand drive left crankarm with a right hand drive right crankarm. i just think drag drag drag from all that extra rotating mass. you should do it just to say you did.

you could use a left crank from a tandem to solve the pedal threading issues - TA (amongst others) do tandem chainsets, and can often be bought as single arms e.g. if you bought left stoker (person at the back of the tandem) and right stoker then you could run chainrings on both. Some examples of left hand drive on FGG:

www.fixedgeargallery.com/2004/d/walter.htm
www.fixedgeargallery.com/2004/e/pmiller.htm

Olly

Awesome, do it.

I think the only "problem" it will solve is the small amount of power lost to flex on on the NDS BB shell and through the BB spindle. Not much. You will increase friction, weight, and probably issues with chainring concentricity.

But then I don't think you're trying to solve anything, right? Really trip people out and run two different but equivalent ratios.

Sure, do it guy.
I do know from my old roomie that it is just a style thing, but that would be neat to run the same inches with different gears. I bet that's even harder to dial in though.

That would be great.

If someone notices the two different sets of gearing, just say "The right side is for uphill, the left side is for downhill "

You guys need to quit scheming.

This is how to make a multi-speed fixed gear bicycle.

Edit: Thinking about it more, I guess that would be impossible. The lower gear would dominate, right?