cog stuck?

i am having alot of trouble removing two seperate cogs from two different wheels. using my shimano chainwhip, i can’t seem to get them to budge. very odd, because i’ve had no trouble removing cogs from both these wheels in the past.

is there a reason they are locked so tight? is there anyway that i will be able to apply move force via chainwhip to remove them?

thanks guys.


I had the same problem as you. Nothing would make the cog budge. Bit of the ol’ rotafix and “hey presto!”. Genius.
Just be sure to use a hefty rag on your BB shell to avoid scratching it up.


I hardly ever use a chainwhip. Rotafix all the way.


I can’t see how using a chainwhip is inferior in any way to rotafixing. Rotafixing is what you do if you don’t have a chainwhip.

Unless your chainwhip is as long as the radius of your wheel you can’t beat the amount of torque that rotafixing can apply, it’s just physics, also eliminates that “ooh I slipped OH GOD MY KNUCKLES” problem that chainwhips sometimes have when attempting to get an extra-tight cog off

If a cog is rotafixed, and then tightens up, what then? Find a bike with longer chainstays I guess… and people wonder why they strip their hubs.

You rotafix it off again. No one is advocating busting a pfoofer valve getting the cog on - just as tight as it will reasonably go with grease.

And I don’t think the forward motion of pedalling is going to do any significant amount of further tightening once it’s rotoed on.

…says the man who has never had to un-rotafix someone cog who thinks the same thing.

thanks for the help everyone. i managed to get both cogs off in no time using rotafix :smiley: