PatrickFish

I'm trying to remove a worn track cog off of my hub. I got the lockring off, and tried reverse rotafixing it off, but still no dice. I'm sure I am apply torque in the right direction, but nothing. Any advice?

randomgear

Penetrating oil, a wee bit of heat (Park Tool Co. » ParkTool Blog » Thermodynamics: What can it do for you?) and a long heavy chain whip such as a Park SR-18. It might also help to have a second person hold the wheel tight as you press hard on the chain whip.

I never got the hang of the rotafix method myself.

cny-bikeman

I know you say you are turning in the correct direction, but you do mean counterclockwise, correct? You can also try remounting the wheel without the lockring attached and stomping on the pedals in the wrong direction. After all the reason for the lockring is to prevent the cog from coming off when you backpedal.

FastJake

Are you SURE you're turning it in the correct direction? The rotafix method confuses me every time, but has never failed me. I don't run track hubs because I want quick release instead of bolt on. So my track cogs are always on freewheel hubs without a reverse thread lockring. I will put a bottom bracket lockring on top if there's room, but there often isn't room.

Keep in mind that the rotafix method can provide enough leverage to break chains or strip the threads clean off your hub. So if that doesn't get it off, nothing will. Penetrating oil is a good start. You can try heat to break things loose. But let it cool down before attempting to remove the cog because the aluminum hub will expand more than the steel cog, thwarting your efforts to try and remove it when hot.

This is a good reminder to ALWAYS USE GREASE when installing a thread on freewheel or fixed cog so that you can get it off later.

ThermionicScott 

+1. I use a ton of grease each time.

When I do want to remove a cog, I'll bang on the chainwhip with a hammer (actually, a big wrench) and that hasn't failed me yet.

FBinNY 

It's a WORN cog, so I assume you just want to remove it and have no use for it afterward. If so, set a dull cold chisel or punch against the base of any tooth, and give it a solid blow with a hammer. OR, if it has an even number of teeth, trap it in a vise, squeezing it hard enough that it can't turn, but not enough to crush or ovalize it, and turn the wheel to the left.

BTW- the punch and hammer method is most effective while the wheel is on the bike and resting on the floor. Stand behind or above, and whack and it'll spin off on it's own momentum.

PatrickFish

I'm pretty sure I'm doing it in the right direction, I looked at some older threads about stuck cogs, and everyone said to toafix it, and referenced this video

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

I'm doing the exact thing he did to get the cog off, I flipped the bike, and pushed the wheel clockwise. For extra measure, I did keep the bike upright, and tried to rotafix it counter clockwise, but still nothing

FBinNY 

First of all, be sure to confidently keep your directions straight. The sprocket comes off counterclockwise if looking from the sprocket side. Likewise looking from the same side the wheel would back off clockwise, but both would be the opposite if looking from the other side. So, however you do the job, keep in mind the direction you turn one relative to the other, not to space.

As for getting it off. Do you know a plumber. If so, borrow a large pipe wrench, latch it to the sprocket brace the wheel and take it off.

Here's an effective way to brace a wheel with a tire on it. Stand it in the corner between floor and wall with the sprocket to the LEFT. Arrange the chain whip or pipe wrench or whatever so you're pushing dwon toward the corner. The added pressure will drive the wheel tighter into the corner where traction will keep it from turning, so you can just about let go and put all your weight into the tool.

WARNING - brace yourself because the sprocket will pop free suddenly and this technique done poorly is a good way to slam your head or face into the wall.

vintage cellar

Sometimes people get confused because the lockring is REVERSE threaded. The cog needs to go counter-clockwise to remove, which is opposite of the lockring. Not sayin' you are doin this. Just sayin . . .

fietsbob

I have beefed up chain whips* with a length of steel tube added to make a long Handle.

* use 3 piece 1/8" chain master links to connect the chain sections to the piece of hot rolled steel flat bar .