I have a Windsor and I need to remove the cog. How do I do it?

Chain whip or google rotofix if you are daring.

Remove the lockring, get on bike, grab both brakes and pedal backwards.

No brakes.

this

ride bike with old cog to buy brakes, add brakes, do said above, remove brakes, return brakes on your bike with new cog

Rotofix, probably the easiest and fastest way.

man, some people here should not be riding a fixed gear.

I had trouble removing my cog to change it out for a 17t. This is what I did; I used a large screwdriver & hammer to bang it loose, then a large pair of channel locks to loosen it all of the way.

I rotafixa'd it on & it wasn't budging. I even did trackstands, rode & skidded w/o a lockring but it was on there good. Trust me, a 3lb mallet & screwdriver are your friend if you're not planning on reusing the cog. Just be careful.

^ don't do this.

Rather than risk damaging your hub, banging on it with a hammer, why didn't you just rotafix it off? Just loop the chain the other way. I've taken off cogs that were so stuck they broke a chainwhip this way.

my rear cog was siezed on my hub the other day. lets just say that was interesting.

+1

Anyone can do reverse rotafix. There's no need to improvise a new chainwhip, especially such a crude hack as described above.

be careful with rotafix messing up your paint work around the BB area - put a rag between the chain and paint!

I went to my lbs. $5 to take off =[.

^ Why not buy a real chainwhip for $10?