Singlespeed & Fixed Gear - Completely unremoveable cog

I built up a Paul set about a month ago and used a surly cog for about 2 weeks. Completely clean threads, greased, chainwhipped on, not rotafixed. Trying to remove this thing I encountered:

4 broken sections of chain on a chainwhip
1 bent chainwhip handle
1 broken allen key attempting to use a chain section in a vice grip with an allen key on the opposite end
1 bruised girl in the shop watching
4 different guys with no success
1 hour of WD40 soaking in the threads
1 broken heart full of dissapointment


Any possible ideas? I've had an EAI cog and new chainring ready to update my drivetrain. I have also encountered some pretty ugly threads after taking off the lockring so I'm a little scared at what I'll find if this thing ever does come off. Maybe I'll wait until winter so the metal shrinks.

Have you tried rotafixing it off?

I don't see rotafix in that list.
if that fails bench vise

wrap an old chain around the cog
clamp the chain ends in a vice
turn the entire wheel

Maybe I'll wait until winter so the metal shrinks.
It's always winter in your freezer, maybe give that a try.

It's always winter in your freezer, maybe give that a try.

Also it's always sunny at the end of a lit blow torch, maybe you can warm up the cog a little. Really though if what dutret and lyledriver suggest doesnt work i'll eat my hat.

It might be cross threaded. When you put the cog on, did it spin easy or did it require a lot of force. If you forced it on it is probably ****ed.

If you put it on OK I would suggest removing the lockring and putting it back on the bike. Do a few intense leg locks with as much weight as you can put on the pedals and the back wheel. It may take seveeral of these so don't give up too quickly. If this doesn't remove it take it to a shop.

loosen the lugbolts a little and roll the car back and forth..

oops wrong forum.

wrap an old chain around the cog
clamp the chain ends in a vice
turn the entire wheel


Tried that with two guys on it, that's how the allen key broke.

I must ride like a monster!

I'm confused. where does the allen key come in?

edit.. OH, you said vice grip.
I'm talking about a bench vice!

I don't see rotafix in that list.
if that fails bench vise

I haven't tried rota fixing off, I may give that a try.

I hope the threads arent cross threaded, I didn't really hulk it on there. I'll try the rota off, but if worst comes to worse I may just cut the thing off.

Unfortunately for you, it sounds like you rode it so hard it went through a state of metallurgy fushigation in which the two metals have fused together to form aluminprioxitanium.

I wouldn't mess with it. I heard that if you break the bond, it could explode resulting in the injuries of thousands.

I'm confused. where does the allen key come in?

edit.. OH, you said vice grip.
I'm talking about a bench vice!


Yeah, bench vise. The allen key was through the chain to try and prevent it from slipping, but slip it did.

Unfortunately for you, it sounds like you rode it so hard it went through a state of metallurgy fushigation in which the two metals have fused together to form aluminprioxitanium.

I wouldn't mess with it. I heard that if you break the bond, it could explode resulting in the injuries of thousands.


COSMIC! Now if I could figure out how to turn lead into gold and water into microbrews!

I haven't tried rota fixing off, I may give that a try.

rotafixing with two people is only slightly weaker then the bench vise method and worlds better then a chain whip or visegrip.

It might be cross threaded. When you put the cog on, did it spin easy or did it require a lot of force. If you forced it on it is probably ****ed.

If you put it on OK I would suggest removing the lockring and putting it back on the bike. Do a few intense leg locks with as much weight as you can put on the pedals and the back wheel. It may take seveeral of these so don't give up too quickly. If this doesn't remove it take it to a shop.

I took it to the shop which is where all this madness took place. The mechanic there is notorious for being able to untighten anything. Little did he know...

Here's a last-ditch idea if nothing else works. Using a dremel tool with a cutoff wheel (actually you'll probably burn through several wheels) cut inwards towards the hub threads as close to the hub as you can get without damaging the hub. A hammer and a large chisel should crack the last little bit and you should then be able to spin the cog off. if not do the same thing 180º around the cog, and it will come off in 2 pieces.

rotafixing with two people is only slightly weaker then the bench vise method and worlds better then a chain whip or visegrip.

Bummer. I'm considering cutting two faces into the cog and placing that in the vise just to get this thing off.

Have you tried yelling at it ? it works for me sometimes..

Also it's always sunny at the end of a lit blow torch, maybe you can warm up the cog a little. Really though if what dutret and lyledriver suggest doesnt work i'll eat my hat.

I think that's how I stripped my crank when trying to remove the pedal...I would suggest against using a torch. The aluminum becomes weaker far faster than it or the steel expands.

Have you tried yelling at it ? it works for me sometimes..

Oh yeah, that's how I got my last cog off and it worked like a charm. No go this time.

I don't think I'll mess with the torch. Placing undue heat near any of my parts scares me if the bikes already built.

easy, just take the lockring off first.

just rota fix that **** off already

if the hub is Al and the cog steel then don't heat it as it will only make things tighter. Al has a higher coefficient of thermal expansion than steel so cooling it down would be the way to go if you are going to attempt this

just rota fix that **** off already
exactly.....takes just 2 seconds.

take off the lockring and skid down the biggest hill you can find....

just rota fix that **** off already

+1 billion two hundred thirty thousand 9 million and two

if the hub is Al and the cog steel then don't heat it as it will only make things tighter. Al has a higher coefficient of thermal expansion than steel so cooling it down would be the way to go if you are going to attempt this

I was actually curious about this as an aside. I'l try the rotafix already, but I'm at work so maybe some other time.

liquid wrench

have you considered changing the gearing on the chainring end of things?

You can buy liquid nitrogen from chemistry supply and possibly welding stores, or a local university.

You can figure the rest out.

get a brake.

get and adjustable type bottom bracket, reverse the spindle, install the drive side crank on the left side, install the wheel backwards so that the cog is on the left side also. you now have a left side drive bike. now, all you have to do is ride it around, maybe hammer up some hills, and always use a brake when slowing down. every time you pedal you will (be trying to) loosen the cog. and, with a left side drive bike you can assert your individuality at the same time.

griffin: My plan was to change out both because these are pretty old and ratty by now.

Hocam: That sounds slightly too complicated, but perhaps the most fun. I'll call Mr. Wizard this weekend.

jamey: Yeah, I ride with a brake, though I'm not sure the relevance.

Kitten: Interesting.

I've considered some of these of the wall solutions, the first on the list is the reverse rotafix, though it's been claimed that's less torque than a vice. I'm sure I'll post again when I get this thing off.

jamey: Yeah, I ride with a brake, though I'm not sure the relevance.

no relevance at all, just seems like most options have been discussed so i figured i'd just throw that in there. for some reason i find it really funny when people throw one of the usual answers to one of the usual questions into a thread you haven't seen a billion times.

someone say rotafix

someone say rotafix

nah, it's been said, but I don't think anyone's recommended that the OP try turning COUNTER-clockwise yet.

Turn it the OTHER way??

sell it to one of these guys that cant keep their cog from slipping. buy a new wheel set. grease your threads this time.

nah, it's been said, but I don't think anyone's recommended that the OP try turning COUNTER-clockwise yet.nah, that would be too obvious....:D

As for the blow torch and liquid nitrogen suggestions, if you really value the durability and longevity of your components I wouldn't take a torch to anything unless you're building a frame or supercool anything unless you're doing some sort of superconductivity experiment on your bike.

Also, forgive me if I've missed this, but has anyone suggested penetrating oil yet? Drench it, let it sit, drench it, let it sit. Repeat for about three days. It's amazing how often that works...

sell it to one of these guys that cant keep their cog from slipping. buy a new wheel set. grease your threads this time.

Good idea, and I did grease it.

I may try letting some oil sit in there for a couple days. I let it soak for about an hour, so maybe it just needs some time to think.

Good idea, and I did grease it.

I may try letting some oil sit in there for a couple days. I let it soak for about an hour, so maybe it just needs some time to think.
did you try HARDCORE rotafixing it off yet?!

did you try HARDCORE rotafixing it off yet?!

Monday.

did you try HARDCORE rotafixing it off yet?!

Is that the sort of rotafixing where you break the chain, scratch up your frame, and separate your shoulder?

Monday.Why wait til Monday if you can do it now?

Once I bought an old Campy Pista wheelset which came with a 7 tooth inch pitch cog. That cog's been on that hub for probably 30 years. I was able to rotafix it off after trying everything else.

Is that the sort of rotafixing where you break the chain, scratch up your frame, and separate your shoulder?
duh

I support the "shout at it" solution. It's what Jeremy Clarkson does in similar situations.

Why wait til Monday if you can do it now?

I wish I could do it now, but I'm at work now and leaving town for the weekend.

did you try HARDCORE rotafixing it off yet?!

it should work as long as you are using the CHAIN OF STRENGTH! zing!!

it should work as long as you are using the CHAIN OF STRENGTH! zing!!

oh wow... my day has been made!