how the chuff do I get this out? stuck BB cup content

Trying to build this cro mega up for the wife to use, only thing standing in the way is this BB cup! Tried heat/vice but it slips out of the jaws!

Any suggestions???

A decent hacksaw blade and patience.

i'm assuming you have tried the correct tool (and have turned it the right way as it's a left hand thread) so after the obvious attempts of using a vice to clamp across the flats there is little more you can do at home with out another tool.

the tool i'm talking about is basically a specific tool for this issue, it looks like a piece of metal bar with 2 flats on it with a section of smaller sized thread on one end with a large nut on the thread, you remove the nut slide the thread through the hole in the cup, the nut goes on the inside of the cup inside the frame, as you do it up tighter it grips on the cup and with some elbow grease and a big spanner will undo the cup.

try and find an old school shop who have this tool, if they don't have it don't bother as attempting to remove this with a specific tool will cause more damage to the b/b area whereas this tool i am talking about just simply does the job.

if you're near southampton GA cycles has this tool. never failed me there when i was managing that shop


oh and the hacksaw thing could work but would take ages, alot of swearing and remember you would be attempting to cut pretty hard steel

Sandvick hacksaw blades work OK - does take a while but there is little risk of damaging the frame, unless you start cutting into the threads.

As per the above post, see here - http://sheldonbrown.com/tooltips/bbcups.html

about halfway down....

I've done this on a couple of 'stuck' fixed cups and it does work. You really have to give it some beans, a long lever and some standing / jumping was required on my part.

here's the sheldon brown ghetto version using a large nut/bolt and some large washers

probably available down the local hardware shop for not alot of pennies

The proper tool works in places adjustable spanners and wide head spanners just cannot cope as they slip of sideways.

jonnyboy666":pn031gjo said:

here's the sheldon brown ghetto version using a large nut/bolt and some large washers

probably available down the local hardware shop for not alot of pennies

Click to expand...

+1 on this one...

Had the same issue with my niece's bike the other day - her BB was noisy and on stripping I found the bearings were shot - a quick trip to my parts bin found a suitable replacement (UN54 Shimano unit that'll probably outlast the BSO itself!).

Getting the fixed cup out was a faff to say the least, after struggling with spanners, mole grips and heat I dug around in my van and found a suitable nut & bolt and it came out easily - as you tighten the nut it should break the threads loose on the fixed cup as (assuming a "normal" BB) it'll be a left-hand thread.

My method didn't use the stack of washers though as not only was the BB was knackered anyway, the nut/bolt were from my scrap bin.

I had this problem with my Ritchey, hardened steel fixed cup from a tange three-piece stuck in the BB shell which has a 3/16" wall thickness (read zero flex).
I got it out by grinding the outer surface down until it could be broken away from the threaded cup inside the shell, then used small dremel grinding cylinders to weaken the inside of the cup - because of the different grades of steel, you will see the chromoly threads in the shell through the cup walls when it gets thin enough. Then I just took a big old flat head screwdriver and a hammer and took it out - as the Slayer song goes - "piece by piece".

I actually have access to the correct shop tool now, but where's the fun in that?

That's why this is the best forum on the net!! Bruised my arm but...


Thanks everyone!