Possibly stuck bottom bracket

[pwa]

Not a crisis at the moment but could be a problem in the future. I have just tried to remove a Shimano square taper bottom bracket (probably UN55) from a steel frame and gave up because:
a) It is okay at the moment and I'm not in a rush to change it
b) The Cyclo tool went in a few mm but may not be a perfect fit, so I don't want to bugger the splines on the bottom bracket
c) I'm inclined to seek out a bike shop with a bigger and better tool

I didn't install that unit. If I had it would have come out by now. I don't know how much grease, and what type, went in.

Question is, given that I have only used moderate force so far, how likely is it that a good bike shop will have real problems?


I wanted to get the unit out to measure it, but I've now done that by alternative means. I've been buying new drivetrain parts from Spa for the spring. I'll run the current stuff into the ground over the winter. Shark teeth profiles all over. New rings needed so I'm biting the bullet and getting an XD based chainset with 46/36/26 TA rings, a new cassette and pulley wheels. And chain. Bank balance now lower and I'm feeling faint. The existing bottom bracket should be okay, in theory. We will see.

[meic]

As you have time, you can use it.
I would keep badgering the BB's grip with easing oils, (moderate)heat and physical assaults over the winter to break its spirit.
It would also make the job easier and safer for the frame threads if/when you do take it to the bike shop for removal.

[pwa]

As you have time, you can use it.
I would keep badgering the BB's grip with easing oils, (moderate)heat and physical assaults over the winter to break its spirit.
It would also make the job easier and safer for the frame threads if/when you do take it to the bike shop for removal.

Yes. I've already started with some WD40 branded "Fast release Penetrant", taking care not to get it near the axle and the bearings. I don't want to accidentally strip remaining grease off the bearings.

[Brucey]

in which case the best thing is surely to drop a load of oil down the seat tube, where it can sit and do some good without danger of getting into the bearings.

cheers

[pwa]

in which case the best thing is surely to drop a load of oil down the seat tube, where it can sit and do some good without danger of getting into the bearings.

cheers

There's a thought! I'll do that.

[mjr]

Question is, given that I have only used moderate force so far, how likely is it that a good bike shop will have real problems?

Not very. Good shops seem to have far better tools and more practised mechanics than most home bike sheds.

I'd always recommend bolting a splined BB tool into the spindle, tight enough so it can't fall out and wreck splines (or tool, if you're really unlucky) but loose enough that it can unscrew a bit before you loosen the nut holding the tool on a bit.

[pwa]

Question is, given that I have only used moderate force so far, how likely is it that a good bike shop will have real problems?

Not very. Good shops seem to have far better tools and more practised mechanics than most home bike sheds.

I'd always recommend bolting a splined BB tool into the spindle, tight enough so it can't fall out and wreck splines (or tool, if you're really unlucky) but loose enough that it can unscrew a bit before you loosen the nut holding the tool on a bit.

Yes, I did that, but I have no faith in the tool and the BB splines being a perfect match, so I'm not going to exert maximum force for fear of just damaging the splines a good bike shop will need to get it out.

[mjr]

Yes, I did that, but I have no faith in the tool and the BB splines being a perfect match, so I'm not going to exert maximum force for fear of just damaging the splines a good bike shop will need to get it out.

Cool. I thought you might, but it wasn't mentioned, so here, granny, have an egg to suck

Is it a plastic or metal cup? If it's a plastic cup, then in the worst case, some shops have a tool that drives loads of pins into it and then uses those to turn the cup. Home mechanics damaging plastic splines isn't that rare.

[Brucey]

the eternal conflict between the unstoppable force and the immovable object means that if the BB is really stuck something is gonna break.

My personal record is (I estimate) over 500ftlbs of torque (using a 3/4" drive breaker bar about five feet long) on a seized BB cup (at which point holding the frame was the main problem). Amazingly the tool didn't break, but if the BB cup had been aluminium not steel, it would surely have failed.

I built a special breaker bar tool (double ended, with big hand grips, about four feet long in lightweight hollow steel) for a chap that worked in an LBS; he had wrist problems and this tool allowed him to exert over 300ftlbs without straining himself. I explained that the tool could be made 'unbreakable' but the things attached to it were not, and never could be. I made the breaker bar with a 'mechanical fuse' that would fail at about 400-450ftlbs, so that a decent BB removal tool/bike wouldn't get broken if the seizure was particularly bad. In the event of failure the 'mechanical fuse' could be easily replaced/renewed. In several years of use he broke it once, and it took two of them swinging on it to do it.

But nothing is unbreakable....

cheers

[fastpedaller]

Apologies if I'm stating the obvious - OP, are you turning the tool in the correct direction?

[gxaustin]

The only time I broke a BB by removing it was when it had been put in by the LBS. I finally shifted it with a stilson and using a 30" scaffold tube for extra leverage. I don't let the LBS near my BBs now

[alexnharvey]

I think the risk of spline damage is greatly reduced by securing the tool in the cup by some means as various others say above. Until I purchased m8x1.0 (fine) bolts I managed with a g clamp or quick clamp, secured by clamping onto the other side of the axle. With a hollow axle you can use a quick release.

[pwa]

Apologies if I'm stating the obvious - OP, are you turning the tool in the correct direction?

I thought so. The left cup is normal thread isn't it? Anticlockwise to undo? Reverse thread on the right?

[David9694]

If you do want to diy it, a better bb tool is worth having anyway and isn’t expensive. I find suspected stuck bits a little unsettling, I’m a bit kill or cure.
If it’s resisting, keep on with the daily dose of penetrating oil and Consider rigging a bb bolt, washers and depending on the tool’s design a spare bb cup or similar to clamp the tool down so it’s got no choice but to turn when you apply turning force. It’s best if you use a bar that applies the lateral force from its centre, rather than all from one side.
I’d recommend inverting the washers and bolt set up into a bench vice - if you have one, you can probably apply both downward and lateral thrust to stop the tool jumping. whichever you do, make sure you turn the appropriate way l/r - English bbs are the opposite to pedals.

[pete75]

the eternal conflict between the unstoppable force and the immovable object means that if the BB is really stuck something is gonna break.

My personal record is (I estimate) over 500ftlbs of torque (using a 3/4" drive breaker bar about five feet long) on a seized BB cup (at which point holding the frame was the main problem). Amazingly the tool didn't break, but if the BB cup had been aluminium not steel, it would surely have failed.

I built a special breaker bar tool (double ended, with big hand grips, about four feet long in lightweight hollow steel) for a chap that worked in an LBS; he had wrist problems and this tool allowed him to exert over 300ftlbs without straining himself. I explained that the tool could be made 'unbreakable' but the things attached to it were not, and never could be. I made the breaker bar with a 'mechanical fuse' that would fail at about 400-450ftlbs, so that a decent BB removal tool/bike wouldn't get broken if the seizure was particularly bad. In the event of failure the 'mechanical fuse' could be easily replaced/renewed. In several years of use he broke it once, and it took two of them swinging on it to do it.

But nothing is unbreakable....

cheers

I've had a lot of success with supposedly stuck bottom brackets using this tool. Bought for other uses not bikes though. Provides impact as well as torque. Such things seem less likely to break stuff than using long bars when loosening. I guess it's the impact as well as turning force that helps to loosen stuff. Some dumbos use them for fully tightening stuff and are then surprised when their car wheel studs snap.....