Singlespeed & Fixed Gear - Cog slipping

title says it all but i need a little help. Every time i back peddle with medium resistance. my cod slips and loosens. I have taken it off and cleaned it put it back on, tightened excessively put the looking ring on tighten that to hell and yet it still slips. Are there any tricks to getting this thing from slipping? How are you suppose to stidd stop without this thing undoing itself

Help!!!

You're 100% positive it's on there nice and tight?

Are the threads on your hub damaged?

no the threads where fine not damaged at all. Im pretty sure the where on there really really tight. I leveraged the hell out of them

http://www.youtube.com/watch?v=5qIVEpyelP0

guessing the threads on your hub got hosed the first time it slipped.

Maybe, maybe not. You just might not be cranking it down as tight as you think you are. If you don't want to rotafix, put your front tire up against a wall with your drive side crank arm forward and put all your weight on the pedal. Bounce a couple of times to make sure you've really got it. Then tighten your lockring.

Thats a good trick to know. I will try and tighten it down that way see if that solves the issue

sounds good I will try that. Im 100% positive that the hub is fine but will check that when I get out of the office for the day

+1 on making sure your hub isn't toast.

Grease all the threads. Get the cog really tight BEFORE you install the lockring. I use the rotafix method, I've never had one slip and they always come off easily reversing the rotafix.

After all that it shouldn't be necessary to kill yourself cranking down the lockring. Just get it nice and tight and you should be fine.

Yeah, more than likely it isn't tight enough even when you think it is. I've tightened the bejesus out of a cog with a chainwhip to where I was convinced it couldn't possibly go any tighter, only to have it slip forward once I mashed on the pedals. Just to re-emphasize what's already been said, tighten with your legs or rotafix, then tighten the cog. Sounds like you've already got the tightening with your legs thing down pat.

Can somebody who's good at graphic design put together a nice infographic for what to do if your cog is slipping? I swear this gets asked every day and we have to type it out in multiple posts every time.

http://204.73.203.34/fisso/eng/schpignone.htm
There is a printable Pdf file also if u need one.

Does this cover it?
http://i.imgur.com/MI9EA.jpg

Epic Wins it ^^

I have nothing against rota-fixing (I used to do it when I had a bike whose BB shell allowed me to), but where does this idea that chain-whips don't work come from? The park tool chain-whip I have is about the same length as the diameter of a 700c wheel, so the leverage is the same.

if your cog is slipping you should realize a couple things,

is it happening on a certain motion for example, on accelaration you might push down with the dominant foot and pull up with the non dom foot considering you use foot retention,

Or maybe it slips when you first start the skid

Or maybe it slips when you push down as hard as you can riding, (acceleration while riding)

If this is happening it most likely is your cog,

If the chain line isnt moving at all and there is crank arm play, Then your chain ring bolts are horribly loose,

The cog is a simple fix, Go to the LBS 5 dollars.