I had an LBS install a Surly 15t cog on the fix side of my Soho-S. Yeah, I know I could've installed it myself, but I was there anyway and they had the time to do it while I waited. I put maybe 200 hard mashing miles on it and life was good.

When I bought my Madison, I decided to remove the Surly cog from the Soho and install it on the Maddy to give me a track-ready 48/15. The lockring came off fine, but the cog wouldn't budge even with the wheel still on the bike and my 250lbs putting substantial backpressure on the pedal

So...I took the Soho to the same LBS who installed the cog and presented the problem. Even with a cheater bar and the wheel on the bike, they could not remove the Surly cog The second mechanic (not the first mechanic who installed the cog earlier) said he was afraid he'd taco the wheel if he applied too much pressure. Now I'm stuck with a 44/15 combo on the Soho that has been relegated to commuting duties to the gym, the store, and easy rides around the neighborhood with my daughter....not that its a bad thing, but wtf?

Could the first mech have screwed up by not applying anti-sieze to the threaded area of the hub before installing the Surly? Or am I just an incredible masher of pedals who destroys things? I haven't been able to make contact with the first mech who installed the cog and the other mechs in the shop have no idea how he installed the cog.

The second mech said its possible my hard mashing, my 250lb mass, and my leg strength may have unfortunately contributed to the stucky situation. I say the first mech may have cross-threaded the cog dry. But even so, shouldn't the soft aluminum "give" when we tried to remove the steel cog with all that pressure? Or is this stuck cog syndrome a common problem with some?

I have backed the bike up against a wall and had a friend hold the bike upright for me while I back-mashed the pedal with considerable force, but it feels as if I'm going to taco the whole damn bike Is this wheel a permanent 15 toofer now? Is it time to buy a new wheel if I want to change cogs?

try the rotafix method, just look it up. using the cranks is not the best way.

I've been trying the reverse-rotafix method this morning, but so far no joy If the reverse rotafix doesn't work, then I'm afraid nothing will

*Update*

I soaked the thread interface area between the cog and the hub with WD40 as best as I could. Even after repeated tries of the reverse-rotafix method, its a no-go I'm not a small man and I put A LOT of my 250lbs behind it....and still no joy. If I went balls to the wall and put almost ALL of my 250lbs behind it, I'm afraid I would break it instead of fix it.

But I've now become scarily obsessed with removing this damn thing at the risk of destroying the wheel just to be able to say the damnbastid cog didn't win! Somebody convince me its ok to give it up so I can get a good night's sleep

Leave it out in the sun to heat up. I've had to do that before.

One other thing you can try is to use the impact method, which is to strike the end of the cog tool with a small sledge hammer. This will multiply the force many times w/o damaging the wheel. This is a job for two people.

This is a job for Bicycle Repairman!

heat and penetrating oil. wd40 is next to useless.

lay the wheel flat and soak the threaded area with penetrating oil overnight. use a torch to heat the cog.

try using a heat gun if you have access to one.

watch joe struggle to remove a freewheel: https://www.youtube.com/watch?v=int3YNN3egk

it won't help you, but always fun to watch someone else struggle

Try a cog vise:

i had a similar problem, now, i dont know if yours is stuck moreso than mine was, but what worked for me was a combination of some things mentioned above:

1) penetrating oil soaked for many hours
2) heat application (let soak outside in summer heat, then blow dryer on highest setting)
3) impact method: hit the end of the cog tool hard with a rubber mallet while friend holds wheel

I had the same problem and I used the Stein Track cog remover. Not a cheap tool, but I just doused it with WD-40, let it sit overnight and put the tool on there and gave it a good pull and it broke free.

PB Blaster is the best. Try and keep it off your bearings as much as possible, though.

PB Blaster FTW