ok, so against sound advice and my better judgement, i rigged up a surly singulator on an old vert-dropout roadbike. seemed to be working ok after several hours of riding. this morning, i wnet over a train trak and the chain jumped off. i figure it was due to a bit of stretch? but, i couldn't get the singulator to hold the chain where it had been, i had no cone wrench, etc...sooooo, i used a piece of wire to secure the singulator arm to the chainstay. not a good idea i know, but i needed to get home and get to wrk. i was pedaling easy and then jumped quick to make a light and the chain just snapped and wrapped around the cog and i went into a skid and walked home. i know very little about the physics of what is going on down there. i generally ride a regular track bike, but had this frame lying around and rigged it up. can someone tell me, in laymen's terms :O), what happend that caused the chain to snap, and any ideas that might make this setup work w/relative safety. i use front and back brakes on this bike for just such and emergency, i don't skid it at all. i would really like to make this setup work. thanks very much.

is this fixed gear (no coasting) or singlespeed (coasting)

if fixed, you CANNOT use a chain tensioner

fixed gear. can you tell me why?

https://sheldonbrown.com/fixed-conversion.html#tension

"You cannot use a derailer on a fixed gear bike, even as a chain tensioner, because when you resist the rotation of the pedals, you would bend the derailer. This presents a problem if you want to use a frame with vertical dropouts as a fixed gear, because there's no easy way to adjust the chain tension. This is also true of chain tensioners sold for singlespeed coasting bikes, such as the Surly Singleator."

a singulator setup can't keep enough tension for fixed gear. try a half link.

The chain tensioner isn't strong enough to support the load put on it by back pedaling.

i know this, i do. that is why i have the brakes and don't back pedal on this bike. if i ride it easy, mostly spinning a small gear and using the brakes and bit of leg resistance now and then to slow down, will it run ok? i don't need perfect tension, i just need the chain not to snap or fall off?

Stop testing your components and just throw a freewheel on there.

I mean, what's going to happen in an emergency, when you don't have the option of applying a "bit" of back-pressure and you crank back on the pedals unconsciously? THAT is when your precarious set-up is going to fail, and THAT is EXACTLY the time you DON'T want it to.

No. Any time you resist the pedals, you will pull the chain against the tensioner, which won't be able to resist enough, and the top of the chain will go slack, leaving it very vulnerable to being caught in the cog, derailed at the chainring, etc.

i hear ya guys, i do. just wntd to see if anyone had any clever fixes for this problem. i even tried the old throw a chainwheel in the loop, and broke window in my kitchen when it shot out! funny, but not good :O) this bike is fired for now! thanks!!!

sounds more like your bike fired you

lol

i lold.

your choices are:
1. keep it single speed
2. magic gear ratio/tinkering for fixed
3. new frame

abe-touche and indeed. fire me it did. eno hub? ahhhh, the hell w/it.

What kind of rear hub are you running? Flip flop? If so, just swap it around, throw a freewheel on there, install your rear brake and be done with it. If not, is there enough threading to install a freewheel on fixed side?

If you insist on running fixed, peabody's options 2 and 3, eccentric hub, or eccentric bb.

It's usually easier to get a new frame that to have that kind of frame work done.

Yeah, looking into it I realize there would be frame work involved. Hell, wouldn't it be easier to just replace the dropouts?

eno hub, or a freewheel with a chain tensioner would be easiest. or even gears. whatever. i never thought i would actually see/hear of anyone do this.

Neither are easy by any means, that's why it's easy to get a new frame. Usually a frame either has horizontal dropouts/EBB, or it doesn't. End of story.

all set guys. lbs has used steamroller and one of the mechs wnts my frame. i'm giving him $50.00 plus frame and he is even going to make the switchover. beater bike back up and running by lunch tmmrw.

All I meant was that setting up your frame for an eccentric bb makes replacing dropouts seem easy by comparison.