So my old cartridge bottom bracket is about fall apart and i bought a UN55 to replace it. The plastic non-drive side was very easy to remove, but the drive side is literally impossible. I let it soak in WD-40 through the night and the next morning i took a massive steel tube and inserted it onto the rachet to increase the applied torque. There was another person putting pressure onto the remover tool so that it doesn't jump teeth. I applied so much pressure that it bent the teeth of the remover tool and soon after the remover tool slipped from its seat and literally destroyed the notches on the bottom bracket. It looks like the frame will go to the trash. I can't get the bb out and the notches that the remover tool bites onto have been completely obliterated. Any ideas on how i can remove the bb? Why is it stuck so tight in there?

Bike: Ballistic Hermes (i think its from 2012) enter image description here

  • 3
    Apologies if it's a silly question, but were you pushing in the correct direction? Some bottom brackets are reverse threaded on one side. I couldn't really find a single article that deals with this well, perhaps just google something like: bottom bracket reverse threaded. If you find you were pushing the wrong way, then it might feel embarrassing initially, but hopefully it might also mean your frame might be salvageable.
    – pateksan
    Nov 28, 2021 at 21:42
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    i tried removing it the other way (without the steel tube for extra leverage) and it didn't work. But how do i know that i am pushing in the right direction? Nov 28, 2021 at 21:45
  • Someone on here will probably provide a definite answer if you edit your question and provide some details of your bike like brand, model and year of manufacture. A photo of the current state of affairs would probably help with getting ideas for the way forward.
    – pateksan
    Nov 28, 2021 at 21:55
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    And the steel tube might be needed for the correct direction in any case, and even especially now because you may have made it super tight yourself first.
    – pateksan
    Nov 28, 2021 at 22:00
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    Consider welding a pipe onto the BB to use as a handle if needed (eg. the tool fitting is useless)
    – MaplePanda
    Nov 29, 2021 at 1:04

4 Answers 4


Unless your frame is Italian, or a handful of unlikely other makes, your bottom bracket is left-threaded on the drive side.


This means to remove the drive side, you have to turn the tool clockwise to loosen it. If you were gorilla mashing on that thing going counterclockwise, you were just tightening it.

It's possible that the flats on the tool going the other way may still be OK, and you might be able to remove the BB if you carefully go the other way.

In general, bikes are lightweight mechanical devices, and even in badly corroded situations, the torque of two people and a cheater bar is not necessary and will just result in destruction and sadness. Next time, step back and think or do research before proceeding if you find yourself trying to put that much torque to any bike part.

  • 2
    @SteliosLiakopoulos look up the manufacturer, but generally italian make frames are only high-end bikes. Your bike is almost surely ISO threaded, so left-hand drive side. Nov 29, 2021 at 16:30
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    +1. Hulking out on machinery without understanding is rarely a good idea. To “destruction and sadness” I’d add “getting hurt”.
    – Reid
    Nov 29, 2021 at 17:51
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    There were many options. Coming here before instead of after getting aggressive is one. Another is looking up instructions on bottom bracket removal (Park Tool has some excellent videos, Calvin Jones is my hero). You apparently didn't even know the correct direction to loosen it. Seriously, the right approach when something isn't working is almost always stop and think.
    – Reid
    Nov 29, 2021 at 21:16
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    @SteliosLiakopoulos It’s really a bad idea to just default to using more force, and that’s applicable everywhere in life. You’re lucky that BB threads are decently resilient. Generally, if you don’t have a plan, don’t do anything. It’s easy to make the situation worse than it started. Welding a pipe or socket on would be my next step.
    – MaplePanda
    Nov 30, 2021 at 0:32
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    @Reid I hope you don't mind me saying this, but to me, your comment sounds harsher than it needs to be. I'm glad to see the OP didn't seem too bothered, and I know some people might say that we should stop being snowflakes. But I can't help thinking some people could really get upset by words like "seriously, (...) stop and think".
    – pateksan
    Dec 1, 2021 at 20:24

The drive side was probably installed without anti-seize/grease, and has corroded to the frame.

Presumably you want to save the frame and replace the cartridge. Starting with oils is a good first step.

  1. Take the wheels out, and the chain if possible. Check the NON drive side and see if it's normal thread or left-hand thread... the drive side will be the opposite thread, probably. So it's a left hand thread on the drive side normally, which can be confusing.

  2. A proper Penetrating oil might help - WD40 is for displacing water and doesn't "creep" along threads in the same way. If you don't already have some, perhaps skip this step.

  3. Add some heat. Use a hairdryer or hot air blower to heat the frame and try to avoid heating the BB. This may work, but an aluminium end-cap will expand faster than a steel frame. Either way you're trying to break the bond between the two parts.

    You can also add more oil which will flow better when things are hot. If you use flame to add heat, there's a chance the oils can ignite, and they will probably smoke. Don't burn yourself (hot metal looks just like cold metal)

    2½: A cheater bar can help, but an impact driver is a bit safer. A mechanical one powered by a hammer blow is safer than a full-sized rattle gun, but sometimes the bigger tool is needed. A sturdy work surface helps a lot too.

  4. Time to get brutal. If you can get the core of the cartridge out, then it's possible to use a hacksaw blade to cut the remainder. Simply slotting it can be enough to release pressure on the corroded threads. Avoid cutting the frame.

    Without an access hole, you may need to use a grinder on the axle, and then a series of drilled holes into the side to achieve a slotting effect and let the cup shrink a little and release. Avoid damaging the tool interface; you'll still need that.

When you're done, the threads in the frame will likely need chasing. A bike shop can do that; the tool is silly-expensive. Or you can carefully work the thread with a pick to clean out detritus.

On reassembly, USE LUBE! Copper clay is my preference, but grease would help too. The corrosion is because there wasn't any barrier, so be mad at the previous mechanic. Make the next guy will be grateful to you for doing it right.

  • 1
    the tool interface has already been damaged pretty badly. It barely grips now Nov 29, 2021 at 13:55
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    It may help to know that some BB cartridge units are held together with retaining compound, which you can get to loosen up by taking a heat gun to it. Nov 30, 2021 at 5:52
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    @Criggie: I tried googling "copper clay lube", but that seems to only turn up results relevant to shining cars. Is copper clay the same thing as "copper grease" (greasemonkeydirect.com/blogs/news/…)?
    – Jake
    Nov 30, 2021 at 10:56
  • 1
    @jake yes - copper-based assembly lubricant.
    – Criggie
    Nov 30, 2021 at 18:46
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    @SteliosLiakopoulos yes - it will be made of hardened steel. You need a sharp hacksaw blade (ideally new) with small teeth, and probably some oil to help the cut. Power tools may help, but they tend to be too big. Remember, don't cut the frame or the threads in the frame. It is a workout alright.
    – Criggie
    Dec 3, 2021 at 22:47

I tried everything that Criggie said. Nothing worked but they were very useful advice.

I managed to get it out by welding a 18mm socket on the bottom bracket's tool interface and then kicking the breaker bar with extreme force to get it loose. Using brute force was the only option.

  • Which way was it threaded Dec 10, 2021 at 17:30
  • @whatsisname the bb is the common english threaded. I removed it by turning it clockwise Dec 10, 2021 at 18:02

Removing stuck bottom brackets where the tool interface is the 22-spline cartridge style and the splines are toast can be truly difficult, and the steps to take depend on the construction of the specific bottom bracket.

Note that there are quite a few cup and cone style bottom brackets on bikes now that use the Shimano-originated 22-spline tool fitting for the cups, even though it's more associated with cartridge bottom brackets. If do you have that style (it looks like the sort of bike that can have it), you're in luck because the plan below is likely to be able to work without issue.

One of the ways of removing a bottom bracket cup with a ruined tool fitting is by using a bolt, nut, and stack of washers to pinch and twist. A socket on an extension is stuck through the shell to get the parts tight enough that when the wrench gripping the outside nut is turned, there's no slippage, allowing further torque to work towards loosening the cup.

enter image description here

This method is excellent if you can make it work, but to do so the cup needs to have enough of a wall for the washers to push against and you also need to get the cup into a state by itself where you can do it, which doesn't work on a unit such as a UN-55 for example, where there is no drive-side cup per se, only a large casing with threads on the right side.


However, many lower-end and OEM cartridges use a simpler form of construction, where there is a discreet right cup. That right cup will be either pressed, bonded, or retaining-compounded on, all of which you can conceivably undo with force or heat. In practice usually it's some kind of retaining compound that will probably come loose if you hit it with a heat gun and then smack the axle through. The cup may or may not have enough of a wall to it that allows you to use the above improvised tool.

chen huar bb

If you're going to try and free it by unscrewing it, I've come to be a proponent of thermal shocking sprays like Finish Line Chill Zone. They get the parts super cold and then take advantage of the contraction to wick in their penetrating oil component.

As Criggie mentions, one possible line of attack (and the main one to look at if the above doesn't work) is cutting slits down the inside of the cup. It's also conceivable with the right tools to cut off the shoulder of the cup and relieve preload that way, then extract with an internal clamp of some sort, i.e. a collet. When those methods don't work, at least by themselves, is when the actual problem is corrosion that's bonding the cup threads fast to the shell material, almost as though they were one piece. The bike in the picture looks clean enough that I doubt that's the problem.

  • well, the bike in the pic is what it looked like when it was brand new. Nov 30, 2021 at 22:24

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