Stuck sprocket

[Deano]

Any ideas on how to remove it?  It's a steel EAI sprocket stuck on a cheap screw-on hub.

It's been in place for a couple of years - since I didn't have a lockring, I made sure that it was tight, and now it appears to be stuck fast.  I've persisted with the wheel even though it's rubbish, but the faff of twisting drive-side spokes past the sprocket is more hassle than it's worth.

So far, it has resisted the suggestions in the fixie FAQs, having a chain whip wrapped around it and being turned in a vice, and brute force with a hammer.

[nuttycyclist]

I'd spray some plus-gas on the thread (careful of the bearings) a few times over the coming days, then have another go.

[Zipperhead]

I carefully went round the join on mine with a (very) small blowtorch to heat it up. Then I put some oil on and left it horizontal overnight to let the oil get sucked in as it cooled (hopefully)

The next morning when I wiped the oil off with a rag it unscrewed the sprocket - previously two of us had applied as much force as we could and it wouldn't move.

[delthebike]

I would try boiling water. Pour over sprocket and hub threads, a quick tap with a hammer on the teeth, in the off direction, and then with the chain whip.

[Deano]

Cheers, guys - there's no immediate rush, so I'll try plusgas over the course of a week or so.  I'll be hoying the wheel out afterwards, so I'm not bothered about protecting the bearings.

Failing that, boiling water.

I was thinking that heat would be a good method - but I don't have access to blowtorches of any size.  It's a pity I didn't think of this in November when I was still working at a factory with access to all manner of heating and cooling things.  Mind you, I doubt they'd have let me play with the welding torches anyway.

[Zoidburg]

A trip to the homewares section of T K Max will snag you a small chefs blow torch for very little money, I have seen them in Aldi as well.

[andygates]

WD-40, overnight to let it soak, then gratuitous violence.  Stick an extension bar (a bit of pipe) on the chain whip to get more leverage and with the wheel braced against the floor and your body, bounce on the whip with bodyweight.

[Torslanda]

I spotted a beautifully simple solution on God's Sheldon's site earlier today.

Get a length of spare chain, wrap it around the sprocket and secure the free ends in a vice.

This gives you the stability of working both sides of the wheel at once with twice the leverage.

If I'm doing the granny/eggs thing then just say so and IGMC

J

[robgul]

Assuming you are willing to risk the teeth on the errant sprocket ... and you have access to a LARGE engineer's vice (that's the vice, not necessarily the engineer  ) ...

.... try holding the sprocket in the vice jaws, no need to be too tight, horizontally.   i.e. the wheel will be flat, on top of the vice with the sprocket underneath.   Then, gently, turn the wheel using the rim like a steering wheel - making sure it's the right way!

I said GENTLY as there is some minor risk of bending, or at least straining, the spokes - but the amount of leverage you can get should release the sprocket before the spokes ping!

It's worked for me - and having had a sprocket come loose on my road fixed, even with a lock ring, I now tighten newly-fitted sprockets with a very gentle "nip and turn" in the vice, before applying the lockring with a hammer and punch.

All of these methods reduce the skinned-knuckles risk from chainwhips and those annoying lockring spanners

Rob

[kyuss]

Reverse rotafix. You might want to protect the BB shell with a rag to stop the paint chipping, but it's never failed for me.

[Deano]

Reverse rotafix. You might want to protect the BB shell with a rag to stop the paint chipping, but it's never failed for me.

That bent the axle when I tried it

I might give it another try - but it's damn stubborn.  Here's what happened to my chainwhip when we tried bracing it in a vice:



It may be worth trying Torslanda's suggestion of wrapping an old chain around it and using a vice.  The thought never occurred to me - and it would have been easier than using the whole chain whip

I want to preserve the sprocket, which has rather limited my use of extreme violence.  I reckon heat's the way to go - I'll ask around to see what people have in the way of blowtorches etc, or try Aldi.

[Fixedwheelnut]

 Don't use a blow torch nearthe hub, the heat from a heat gun as used for decorating will be enough and less invasive to damage surrounding metal

[Deano]

Don't use a blow torch nearthe hub, the heat from a heat gun as used for decorating will be enough and less invasive to damage surrounding metal

Aye that's the sort of thing I was thinking of - I know someone with a BIG blowtorch and it ain't going anywhere near my bike

[Zipperhead]

I used a very tiny blowtorch on mine - flame the size of a pencil tip. I didn't want to bork the bearings.

[nuttycyclist]

That sounds like the blowtorch I used on my bike the day I set it on fire...

[Crumbling Nick]

I spotted a beautifully simple solution on God's Sheldon's site earlier today.

Get a length of spare chain, wrap it around the sprocket and secure the free ends in a vice.

This gives you the stability of working both sides of the wheel at once with twice the leverage.

If I'm doing the granny/eggs thing then just say so and IGMC

J

Thanks for that. I for one had missed it and have been struggling with soft jaws in the bench vice (and worse contrivances) to avoid the damage to sprocket teeth from clamping the cog directly in the vice.

[robgul]

I spotted a beautifully simple solution on God's Sheldon's site earlier today.

Get a length of spare chain, wrap it around the sprocket and secure the free ends in a vice.

This gives you the stability of working both sides of the wheel at once with twice the leverage.

If I'm doing the granny/eggs thing then just say so and IGMC

J

Thanks for that. I for one had missed it and have been struggling with soft jaws in the bench vice (and worse contrivances) to avoid the damage to sprocket teeth from clamping the cog directly in the vice.

As an add-on to the bench vice method in my post - positioning a couple of bits of soft wood in the vice jaws would allow them sprocket to bite without damage to the teeth.   (I have a pair of home-made wooden "soft jaws" for the vice - each is a thin piece of ply glued (at right angles) to a bit of tile batten the length of the jaw)

Rob

[Crumbling Nick]

I spotted a beautifully simple solution on God's Sheldon's site earlier today.

Get a length of spare chain, wrap it around the sprocket and secure the free ends in a vice.

This gives you the stability of working both sides of the wheel at once with twice the leverage.

If I'm doing the granny/eggs thing then just say so and IGMC

J

Thanks for that. I for one had missed it and have been struggling with soft jaws in the bench vice (and worse contrivances) to avoid the damage to sprocket teeth from clamping the cog directly in the vice.

As an add-on to the bench vice method in my post - positioning a couple of bits of soft wood in the vice jaws would allow them sprocket to bite without damage to the teeth.   (I have a pair of home-made wooden "soft jaws" for the vice - each is a thin piece of ply glued (at right angles) to a bit of tile batten the length of the jaw)

Rob

That was one of my discarded 'contrivances' - the sprocket teeth tore through wooden soft jaws. Unsurprisingly, the technique had worked well when I lived in the East where the steepest hills were railway bridges

[Deano]

Free! Free!  Free at last!

It was the big ole blowtorch in the end, since I don't know anyone who admitted to owning a chef's blowtorch.  It wasn't a delicate approach, but since the wheel and hub were going in the rubbish anyway, it didn't matter.

We heated the entire area liberally (there were some interesting flame and smoke effects), then one of us braced the wheel while the other smacked the sprocket with a heavy hammer. 

The sprocket's off and ready to roll again