whilst doing a ridicilously long skid. No injuries. Ran it too loose. Oh well.

Wait a minute - the chain fell off your brakeless bike and you're not dead? WOW!

yeah that happened to me. a week later i got a chain tensioner. a week after that i got a front brake.

As I said, the rear did not slide forward, the chain was just a wee bit too loose

My last chain off was when I was riding home side street. A kid had arranged 4, 1 foot ramps in a row, 4 feet apart.
I came bombing down the street, gave the kid a look, he smiled so I started jumping them ( forgetting I was in high gear, my chaintensioner works only 3 lowest cog) and jammed it beside the chainring after the third ramp.

Had to do a major de-tangle, talked to the kid about what NOT to do with a jump bike.

I'm 38, kid was 10 maybe, we both like little ramps tho- (bet the kid was bustin' moves all day no probs.)

Well I did, after cleaning all the chain grease off my grips, build a 2 footer @ home and jumped it a few time IN LOW GEAR!

It's good to be humbed once in a while, being too ****y on a bike can be dangerous.

I realize I am a heathen, mtb, have a rear Der,....I do only run a mono-ring front?...forgive my trespass
.

what exactly happens when the chains derails on a fixie? not yet had a chance to watch. i have fears of it ripping spokes or my leg off but i think that is just some bike castration anxiety...

When your chain derails, all you can hear is the clomp-clomp of the four horsemen of the apocalypse. Shortly thereafter, you realize that they're sissies compared to you because you don't have a brake. After pulling a Flinstone style stop 2 inches past the white line that demarks the ped-X from the busy intersection (coming down Castro into Market, in my case), you come to understand that brakelessness may be for the masochist, but pain (or the potential for it) is what reminds us we're alive.

i.e. Run-on sentences mean I'm hammered and it is bedtime fo' sheezy.

but where does the chain go? is there the potential for it to snag on something important like spokes, legs, etc?

The fun is in contemplating which of the multitude of fates shall be yours.

Will you just lose the chain and go about your life? Will you rocket uncontrolled into the intersection? Will you bust your nuts on the top tube as you slip off the pedals. Will you completely bail and get roadrash on your forhead? Will it lock up the rear wheel? Does it matter?

Choose your own adventure, dude.

Yeah, none of the options is fun. Even more motivation to check the chain regularly to ensure proper line, lubrication, wear and tension.

I had a chain break in three places while sprinting up a hill. All of my weight went to one side, and I tipped over in slow motion in front of all my friends. They were nice and pushed me up the rest of the hill so I could fix the chain.

I built a tensioner, no idea if of use as a design for SS bikes, 16mm film projector parts.

Is it that with the SS, Fixed desireable horizontal drops, the wheel pulls foreward and you get the chain suck?

Unfortunately, a chain tensioner would not work on a fixed gear bike. Backpedaling would rip it off.

But would that still apply with a non-standard (specifically, no teeth) tensioner such as the one pictured above?

I think someone should experiment with this design on a fixed gear - a fixed, toothless tensioner. I can't see why backpedaling would rip that tensioner off.

I agree. The tensioner in the pic seems like it would work fine. I'm not a ME, but it looks fine.

im more concerned about the bike....

what if the chain got caught on the back wheel and and.. and did something to my baby (the wheel) or its mother (the frame)???

faces heal (torrin) brain cells are overrated (i do just fine). but i got a family to look out for..

Dunno, it could happen.

As for the tensioner, it will still probably snap. On forward pedaling, the tension is along the top of the chain run as the gear pulls the chain taut. Slack accumulates at the bottom and the tensioner takes it up. Backpedal and that's reversed. Snapping the chain outward will probably pop the tensioner arm off the frame.

At least that's my understanding.

That thing wont come off 'till I unbolt it, clamp=chromoly,armature=cast Alu alloy,wheel=rubber\steel core\spinshaft, bolts\nutz=tempered steel. It's on a monoring mtb running 7spd rear. I torque super heavy.

Jumping onna big pointy rock would mess it! = why I cut me up a bashring.

Spins backward fine? Ummm, maybe a spring/ float design would be better for your bike types?

frontside.

I'm trying to understand your earlier messages. Are you saying that you've got this tensioner on a fixed setup or a single-speed?

did you actually use that thing on a fixed gear bike? i dont think the laws of physics would allow it to last very long

https://www.bikeforums.net/mountain-biking/70134-old-school-mtb-pics-got-nice-one-i-do.html

7spd rear, single front ring. I was just tossing in ideas for the 'builder' types.

I don't have a SS bike...yet, I like the idea and have a courier friend who rides one.

My bikes a deconstructed mtb reduced to 7, simple for a mtb I guess.
I intend to go 10-30 rear if possible ( I live close to the North Shore, it's all hills, dirt, moutains.)

Or maybe a 5 rear cluster so I can run a thick fat chain.

Sounds like a cool setup, but that tensioner would probably be crunched to bits on a fixed gear. On a freewheeling setup, there's no tension (to speak of) on the backwards pedal.

yea, go try out that tensioner on a fix... I wonder if it would hold up, but you better have a brake on that thing when you try it. I bet it wouldn't hold up in a decent skid.

I haven't had any problems with my chain, but my buddy got his pants caught in his chain and it chewed up the threads on his hub.

I saw tensioners for SS.https://sheldonbrown.com/harris/singl...tml#tensioners

White Industries Fixed/Free Eccentric https://sheldonbrown.com/harris/fixed-hubs.html ???? can these be used fixed?

"These hubs feature an eccentric axle mount, finally allowing easy conversion of your existing mountain or road bike to singlespeed or fixed gear without the need for kludgy chain tensioners, even if you've got vertical dropouts!"

The Singleator and other chain tensioners will not work with a fixed gear. The ENO however will as it's not a tensioner at all. It's an eccentric hub. The attachment points for the hub are not centered on the hub body, so you can shift the hub body back and forth to take up chain slack without having to change mount point (important if you have vertical dropouts).