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[stefaand]

How on earth do you get this thing off? I bought a 40mm socket, holding the sprocket in place with a wrench I've been hammering on my socketwrench and the nut just won't move a micrometer! nothing! The little worm that's supposed to hold the nut in place is gone as well..I suspect the PO used KN instead of N to torque this thing! any tips?

[Gwilly]

Keep the chain on and use your size ten boot to hold on the back brake, thus locking the sprocket..

A half inch drive by three foot breaker bar held upright will allow you to pull on the bar and stand down on the brake pedal..

Perhaps a little warmth applied to the nut with a blow lamp first may soften any loctite that may have been applied by a PO..

Next line of attack would be an air line rattle gun or at worst a nut splitter..

Show it the big bar though and it will usually surrender without a fight..

[stefaand]

well the whole bike has been disassembled. It's just a frame now and a gearbox casing with a sprocket

[Gwilly]

Heat is always your friend with this kind of shifting exercise, Not cherry red but spitting hot..

Can you bolt the box back into the frame just to hold it still on the floor.whilst you work?

[mauri]

if you have a bench vise with aluminum protectors, you can hold in there to unscrew the nut and ad little heat as posted above.



an impact wrench also help’s.

[stefaand]

I put the gearbox into my workmate.
To illustrate: i've broken off a piece of the sprocket just from sheer torque from trying to undo the nut...is it left hand threaded or something? I've persuaded my brother to buy a burner for his crème brulée, it will arrive on tuesday so I'll give that a go then as well...

[Gwilly]

Too much pressure on one tooth using a wrench.. It would be better to use an old chain around the sprocket to spread the load and trap the two ends of the chain in the work mate..
Engineers vice is the tool to use really, doubt if the wood would hold without splintering..

[Gwilly]

Sorry meant to say normal right hand thread. Anti clock to undo..

[jenks]

I rather think that it is a left handed thread so that it is kept tight by the drive ,rather than being loosened
Cheers
Hope I am right!

[Norm]

Right hand thread and a rattle gun, there is always the possibility a PO has used Loctite so you never know