singlespeed chain tension
 

what kind of chain tension should one be running with a single speed? Not fixed, freewheel.

There isn't much information around the internet about this, or at least when I search I always come up with fixed gear chain tension results.

I kinda figured a tad looser than if I were running fixed would be fine. But seen a few singlespeed videos on youtube and their chain is flapping around like crazy.

Thanks.

Just tight enough to not drop the chain.
Once you go slack, you never go back.

1/2" of play up/down

i've run it even more slack fine tho.
had the chain jump once but my chainline was shîté

Loose enough so that it doesn't bind. If you're dropping your chain, it's too loose, or your chainline isn't straight.

i think the can tension should be about the same as when you are riding fixed, on my bikes i have very very little play, if any without binding, of course it is a big process when i tension my chain. I HATE CHAIN SLACK!!!!!!!!!!!!!

Googling bmx chain tension brings up more results. Some people are saying they like a 1/2" of "sag" in their chain. Actually one guy said that.

The consensus seems to be 1/2" total up and down movement.

Another good one someone said is if you throw your cranks backwards and it freewheels for at least 1 rev before stopping you are good. If it stops before, it's too tight.

Thanks. Guess I will tighten it up a tad.

so tight that it cant spin.

My single speed mountain bike has a derailer because im lazy:|

What do you mean so tight it cannot spin? Can you elaborate a bit please?

I have noticed a few things -

Flipping the bike upside down and spinning the crank - looser chain will start to pull the crank around, tighter chain won't (the crank will just stand still and freewheel).

Same goes when walking the bike, the pedals will turn. Of course only until my clip/strap hits the ground, then it will start to freewheel.

So I realized how bad off center my chainring was. Spent like an hour trying to center it. Got it pretty much perfect, go to tighten it for good and one of the bolts was giving me an issue, kept spinning, go grab my chainring wrench (which is a pos invention btw) and the back part pretty much tears in half. Ugh, now I have to ride with 4 bolts until tomorrow. Hope the LBS has one. At least the back part should be standard sized I hope.

To answer your original question:

http://img217.imageshack.us/img217/4...e5bde58d64.gif

Thanks DSH, that is helpful.

Damn, that is pretty loose.

I think I'm already bored of single speed anyway.

No, single speed is bored of you.

I rode SS and tried to shift :(

Wouldn't doubt it, probably is. I am a boring individual.

http://img210.imageshack.us/img210/7151/sosenka3.jpg
...

Forgive my ignorance, but why would a ss chain need to be any loser than a fg chain (outside of a dropped chain being potentially more devastating on a fg)?

it doesnt?

A good rule is a half inch of sag... a too tight chain will slow you down by putting a lot of stress on your drive train as the chain will try and pull the chain ring and cog closer together... this is what happens when a chain binds.

You don't want that.

It's not that is has to be looser, it's just that it can be looser, and it's not as critical that a precise tension be achieved. Basically, as long as the chain isn't running tight at any point and isn't flopping around wildly, it's ok. I just set up all my bikes, both FG and SS, pretty much the same with about 1/2 total up/down slack at the tightest point.

Like TT said, it's not that it has to be, it's that it can be.

On a fixed gear the likelihood of your chain dropping is greatly increased by the tension constantly switching back and forth between the "top" section of chain (when you're accelerating) and the "bottom" section of chain (when you're resisting/skidding). The slack constantly flipping locations can lead to the chain bouncing around a lot more, and increases the likelihood it will grab the side of a tooth and jump off the cog/ring.

That's not an issue with a freewheel, so you can run a little bit more slack if you prefer.

I would never dream of running fixed with the amount of slack I posted above.

So what kind of rules of thumb are in place for fixed gear tension? I used to run my tension probably a bit too loose (maybe a cm of play up and down?), til someone at a LBS told me otherwise. Now I crank the wheel back and there is very little play, but I'd like to avoid binding and the associated drive train wear/loss of efficiency.