I was bloody relived I could get the bb apart that I just rushed ahead and fogot to take note of how it came apart.DOH!!

I now have the following dilemas

1)What size bearings were they again(dont ask where those bearings went)

2)which side does the longer side of the axle go in

3)which is the fixed cup and which is the adjustable cup

Am guessing the one with more threads is the adjustable cup and goes on the non drive side.

enter image description here

enter image description here

  • 1
    Was blood shed on this project? Hope you are OK!
    – David D
    Mar 30 '19 at 18:18
  • no . It's paint. I was trying out the so called orange paint pen to touch up the decals on my mtb. Its no where near the orange. It also leaked a little because apparently pushing it onto the paper makes it leak.
    – Ageis
    Mar 30 '19 at 18:30
  • Is throw it in the garbage and get a new, sealed BB an acceptable answer? Modern BBs are so much better and so cheap it's not worth the hassle of dealing with loose ball BBs Mar 31 '19 at 14:44
  • @whatsisname : unless it's a vintage restoration project but still!
    – Carel
    Mar 31 '19 at 16:01

Here's a link to a comprehensive description of what goes where along with bearing sizes.
Quick summary
- Long side of the spindle goes to the crank side, right
- Fixed cup goes on the crank side, right
- Bearings - see chart at link (after re-reading the chart I don't think it applies. Can someone else help?)
Do you have a lock ring for the adjustable side?

  • Bearing size is 1/4" on Raleigh cottered cranks (I'm assuming that this is a Raleigh or a similar design); see description of cup/spindle fit here.
    – JonR
    Mar 30 '19 at 23:20

In most cases the longer axle end goes on the sprocket side.

The two cups presumably have opposite threading, one "right-handed" (normal) and one "left-handed" (backwards). The right-handed ("normal") cup goes on the left side, and the left-handed cup goes on the right side.

With some BBs, both cups are "adjustable", to allow the shaft to be moved left or right a few mm to line up the chain with the rear sprockets. But in most cases one cup is "fixed", meaning it has a sort of lip or flange on the outside end that determines how far it can be screwed in. Usually this fixed cup (if either is fixed) is on the right (sprocket) side (but of course the threads of the cup might say otherwise).

So normally the fixed cup is screwed in until it's flange is tight against the BB housing, and then the other cup is screwed in sufficiently to achieve proper bearing motion.

But it's unclear whether the flange is present on your cups. It sorta looks like there's something on the left cup in your top picture, but it's hard to say for sure.

Note that, unless a cup has a flange on it so that it's screwed tight against the BB housing, there should be a lock rings installed to maintain the position of the cup and hence the adjustment of the bearings.


As to your bearings, it's hard to say. If you managed to save even one original ball then you can take it to a bike shop to be measured and buy new balls to match. Otherwise, take all three pieces to a friendly shop with knowledgeable people and they should be able to find the balls to fit.

(Of course, there's some chance the original unit used "caged" balls, but in general loose balls are superior. Installing loose balls can be a cute little puppy, though, so if you're wondering about that task a separate question may be in order.)

  • The surface of of one of the cones is badly pitted it will run very poorly. The 'dull' cup doesn't appear to be healthy. The axle appears to be for a cottered crank where new pins will be hard to find.
    – Carel
    Mar 31 '19 at 16:00
  • @Carel - The dull finish doesn't tell you much -- it's just a different metal composition. Can't tell for certain from the photo, but the cup does not appear pitted. You are right that the axle is for an (antique) cottered crank, but if that's what the bike had then that's what the crank arms are designed for. If needed, new pins are readily available online. (But the OP does have to be careful to install things facing the right direction, or the crank arms will not be 180 degrees from each other.) Mar 31 '19 at 18:23
  • Take a look at the axle! Blow-up the picture IMHO the cone looks rather pitted, especially at the long end.
    – Carel
    Apr 1 '19 at 18:08

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