MLPROJECT

i have a DA cog stuck on some suzue JRs (or whatever came stock on khs aeros laced to arayas). i've tried penetrating oil/lube, wd40, etc etc and no dice. i've also tried putting my whip in a vice and using the wheel's leverage and that didn't work either.

i know the cog isn't loctited on because i have had it off in the past, but its probably been about 8 months since then.

anything else i can try?

jacobpriest

use one of those tomito chainwhips?

Ill Mitch

Just give 'er
or get someone to help you turn the wheel while it's in the vice?

sers

ammonia. it will dissolve any rust from your aluminum hubs. sometimes when steel and aluminum meets, this happens.

baxtefer

reverse-rotafix?

Aeroplane

Ride it brakeless without a lockring. Murphy's Law will remove it for you.

isotopesope

as sers mentioned, try ammonia to remove any oxidization. if that doesn't work, sometimes heating it up with a torch can help too.

HereNT

+1

Also, you could try holding the teeth in blocks of wood in the vice, then turn the wheel... Some shops have a specific tool for doing this with little pins that fit around the teeth and hold it really tight...

WithNail

I have this problem too... I tried reverse rotafixing and it didn't work. I'm trying to be really careful because I don't want to mess up these hubs. Ammonia... really? will it damage the hub at all? I'm in no hurry though... I really want to try that thing with the teeth in the blocks of wood.

hyperRevue

+2 for reverse-rotafix.
You can get unbelieveable torque with that.

LóFarkas

If you try the vice thing, you'll probably need L-shaped blocks of wood that hook up to the side of the vice. Otherwise, they will just slide out in opposing directions.
At least, I think they will. And I think I remember somebody had that happen.

Once I got a cog off by wrapping old used chain on the teeth. It sort of worked, but it was a bit dicey even with a huge bench vice. It even scrathed the vice a bit. Trouble was, it was a 15T. So, on one side only one point contaced the vice. If you are lazy and have an even-tooth cog and a bench vice, you could give it a shot.

MLPROJECT

i'll try reverse rotafix... and the ammonia then woodblock vice thing tomorrow while i'm in the metals shop if rotafix doesn't come thru

r-dub

heat = very bad idea. Aluminum expands far more than steel does when exposed to heat. That means that your hub would wedge even tighter into a steel cog if you hit it with a torch.

gorn

So maybe put the wheel in a freezer?

sivat

put a 3 foot length of pipe over the handle of the chain whip. leverage = good.

sivat

As far as the heat issue, the idea behind heating has more to do with cleaning than expansion. The heat burns away a lot of the dust, dirt and impurities that will lock a fastener in place, making it easier to loosen. Aluminum will expand more than steel, but it will also cool more quickly. As long as you wait 10-15 minutes before trying to remove the cog after heating it, the expansion won't be much of an issue.

muftek

i think im having this exact problem! my cog is stuck on my hub or something and the pedals wont stop turning. it gets really annoying when im going down a hill or want to coast. i dunno how to fix it. maybe my chain is stuck on the wheel? either way, i need help!

Landgolier

I've never gotten the blocks in the vice thing to work, the blocks always skate out. Maybe if you routered the blocks to fit the vice jaws, but that's getting kind of rube goldberg.

You can try a hair dryer and then ice on the hub, but I wouldn't fire up the torch. I don't personally manufacture them, but I'm guessing that cogs have some pretty righteous heat treating you wouldn't want to mess up.

isotopesope

unless you're sitting there until it's red, heating a cog briefly with a limp wrist torch isn't going to do anything to the heat treating.

HereNT

OK - this is the ULTIMATE thing to get a cog off. I only drew like half of it since I'm not that good at drawing anymore.

Anyways, it's an upside down L shape of about 1/2" thick metal. One part goes in the vice. Two bolts thread through the top part that have nuts (not shown) to help hold the cog in place when you're first putting it in place. A total of four pins stuck up about 1/4" from the top, and fit around the teeth, totally locking down the wheel.

Put it in the vice, turn the wheel, and you'll probably never ever have a cog that won't come off again.

I wish I had a vice and knew where to buy one. At least I know what LBS to find one at.

Moximitre

Use your teeth, they are useful for bottle caps, why not stuck cogs?

sers

ammonia dissolves grease, so be careful around your bearings. worst that will happen is that you'll have to regrease your hub or pop in a new cartridge bearing. it just so happens to *instantly* dissolve aluminum oxide. both properties can help. if it's rusted on, or if it's seized because the threads are covered in a greasy slag then you should be able to unscrew the cog easily after the ammonia.

chuck_norris

Withnail,

Have you ever overhauled those hubs? There's a special tool to pop off the tapered metal caps that partially cover the cones. If you or someone you knows has a really strong grip, it can be popped off by hand. I've seen it done, but I couldn't do it. Like sers, said I would plan an overhaul if you decided to soak the cog in anything.

fixedpip

I just ran into this same problem. Ended up having to use the vice method with an old chain wrapped around it and lots of a penetrating oil. Still it ended up requiring two people to break it free.

This cog had only been on the bike a month and was greased. I was recommend to use something like CopaSlip or any grease designed for High torque parts (such as motorcycle bolts) to avoid this in the future.

LóFarkas

I wonder what it will be like when I try to get my cog off after riding through (part of) the winter... The hub is crap soft Al, so I expect it to oxidize. The cog is crap steel, so I expect it to oxidize. I *think* I greased it...