I've got an old Japanese steel frame road bike. Recently, the bottom bracket grenaded itself on me. It had cages, but they got all mangled. As a temporary repair, I used some extra 1/4" ball bearings and packed them in a complete array with grease in place of cages. Sidenote: This happened the day before a century ride, and it survived without any problems. When I got a new bottom bracket (sealed unit), the plastic cup snapped on me. Turns out the threads from side to side are not concentric. The shaft sits off center, and as a result the cup won't line up. I tried to force it straight with the metal cup that was originally on there (it's machined to seat properly, luckily enough) but the shaft binds in the hole since it's off center.

Do I have any options, or am I SOL? I don't really want to toss this frame since it's my commuter, but I end up having to repack the bottom bracket if I get caught in the rain because it gets all full of water. I was thinking of threading in the sealed unit and trying to bend it upward with a prybar, but I have a feeling I'll trash the bottom bracket before I get it straight.

Thanks, guys (and gals).

wow....my back hurts and my knuckles are bleeding from just reading this.... sell it as is and invest
in a new ride-- im serious dont be cheap--- get a pinarello and invest in a good local mechanic....
take it to a guy who will do this right-- if your spending for parts spend for knowledge and proper tools.

My question is what is the "right" way to repair it? Is there one?

FWIW, my back feels fine due to my workstand and proper working height, and my knuckles are free of cuts because I do use the proper tools. It takes me ~10 minutes to pull the BB. I'm a certified auto mechanic, bikes are way WAY easier to work on.

using free bbs without cages is fine with me--- the cups have a size the spindle has a size---
it sounds as though the cup is cross threaded or its the wrong cup--- can you re-position what you had after re taping the frame threads-- not all sealed units come marked correctly-- I have put one in backwards once because I took for granted the drive side "it looked right"--- if the frame is not cracked--- re tap the frame and start over keeping score of numbers---

I don't have a problem with free ball bearings either, they just aren't exactly low maintenance. For a commuter bike, that's no good. I want to use a sealed unit. I'm pretty confident that the cups aren't cross threaded since they thread in all the way separately. The frame isn't cracked. Unless I have a machine, I don't really have any way of ensuring any threads I cut will be concentric, right?

You should not have forced anything. Basically one of two things happened

1) You ****ed the bb threads in your shell
2) Or you didn't

At this point take it to a shop that can chase the threads for you - they may still be salvageable. NEVER force anything into a bike especially if it's something that can be crossthreaded.

If the threads are screwed then your only option is the YST bottom brackets which do not require any bb shell threads to be installed. Downside is that these bb's are of extreme shyte quality. Sometimes it's great to be a hack home mechanic and DIY without expensive shop tools, this is not one of those times.

I can say for a fact that the threads are fine. I know when a thread is about to strip, and they certainly aren't. The cups thread in fine independently. They seat flush against the tube, so they aren't cross threaded.

I hardly consider myself a hack...

Why does it always have to turn into a flame fest?

Sorry I meant that as a term to be proud of - not as a flame. At any rate - your description of the symptom is contradictory. Your threads can't be fine AND have the unit go in crooked. One of them is obviously not correct.

Since we can't see the bike, we either take your word that the threads are fine or the other unlikely possibility is that your bb cups are screwed up somehow. Threads can be fine but still be "not fine" because of crossthreading. Up to you to tell us which one it is.

Take it to a shop if it isn't terribly inconveneint and get your diagnosis confirmed.

I dunno- loose balls with grease work pretty darn well for me- less friction and longer lasting than cartridge BB's. If your BB shell is threaded crookedly, then you may not be able to put in a cartridge BB unless you get it rethreaded, and even then you may not have enough good threads left. So, for water intruson in a cup-and-cone, I'd do two things:

1) Drill a hole in the bottom of the BB shell to let the water drain
2) Put in one of those accordian-like plastic shields that isolates the BB bearings

Check it and regrease it periodically, and you're good to go...

I've had a bike I built for a friend do this and got around it.

First off if you loosen the main body of the BB a turn or two can the other side now be pushed over to center? If so the outer face is off and is wedging the BB to be crooked. This is by far the more common malady rather than the threading being off center.

Assuming it is the lip that is levering the body over there's three ways you can go. First is to leave the main body a little loose until you get the new plastic ring into place and only then tighten up the main body but don't over do it. Just enough to lock it firmly without overstressing the rather small contact point and threading. This isn't the best option for a regular commuter since there's a risk it'll work loose. Second is to have a shop with the right facing tools cut the facing so it's square with the threading. Third is the cheapo in between way that requires a bit of skill and judgement but will get you by if you can aim a file with good results. And that is to note the contact point and then file the edge of the shell down yourself to get rid of the contact point. This last one is the option I used on a rescued bike I fixed up cheaplike for a friend to allow them to join me for rides. If you do this it's not bad. Work the first high point down a bit and a little to either side. Run a ring of felt marker around and screw the BB in and with the wrench work the tightening point back and forth a bit. Remove and file down the new wear marks in the marker ink. Remarker it and screw the BB in again... etc... etc....etc After a while you'll have worked it down enough that the BB sits on quite a few spots and the other side is centered enough to let the plastic ring fit into place easily. At that point one last cleaning of the threads to remove any file dust, grease everything up install the BB and plastic bushing. Then sit back, rest your arms and smile at your command of old world machinist skills

ok--- the bolt holding the cable guide is interfering with the bb casing---ok
did you put the bb in backwards-- and the prize goes to

This is the first useful thing you've posted.

Good point. Check the bolt that holds the shift cable guide under the bottom bracket shell. A too long bolt won't interfer with a cup and cone bottom bracket but can keep a cartridge form installing correctly.

hey, hey, snarkyness just makes me drink and smoke more........

Drill a hole... duh, why didn't I think of that?

I'm pretty sure it's the threads that are off, because the cartridge sits off center before the face seats against the shell. I got rained on pretty good this morning, so I'll be taking it apart tonight and I can check. If it is the face, I'll give this a try.

This was my first thought, but I have a rivet instead of a bolt. I would think a rivet would deform to hardened steel, but I pulled it back almost all the way out anyway.

Thanks for the input, everyone! The only real problem I have with free BBs is they can't handle rain (as is). Secondary to that, the cups were made for 1/4" BBs in a cage, not free, so there's a little more play than I'd like. Can you still get cup and cone bottom brackets?

The cage won't impact anything other than the # of bearings you'll need. Most will suggest using loose bearings instead of caged anyway.

ok--- use a full set of loose bearings( dont mean to be snipey)and the proper size conforming
to the races--- I have used ill fitting bearings and it has been offset--- please do not take this
wrong--- the bearings in the cages are not enough to fill the gap left by the cages--- these loose
bearings must be shiney, not black... and conform to the spindle race as well as the cup--
If you already knew this than I appologize--- if cartridge-- use grease or anti sieze on your
installation-- not necessarily on the frame, oops somethings burning--- ill check back