Hi All,

First post here so just a quick hello before my post!

I've recently been a victim of bike crime...they stole away my beautiful road racer. Nevermind. However, I've got my hands on an old Raleigh SXC 501 Frame. The only problem is the bottom bracket was broken. I've taken it apart and I'm not sure what to replace it with.

I'm sure it is a 68mm - 115mm. I've attached pictures and also i've attached a link to the bb I think I can replace it with....just need some advice as I'm a total newbie!

Thanks in advance!

Shimano UN54 - https://cgi.ebay.co.uk/ws/eBayISAPI.d...m=310208836502

The UN54 will probably work. The only remaining variable is the taper. Read this.
I've found that the plastic fixing side on that particular BB can be prone to cracking.

Thanks. As for the ends where the bolts would go...what fitting would go in there? Allen key crank bolts?

I was thinking maybe just replacing the cage bearings instead of buying a whole new unit. As you can see on the image the cage bearing from one side is completely ripped in half.

1. allen key or hex head bolts will work
2. Yes, if the spindle and cups are reasonably OK, just replace the bearings. You don't need the cage. Take a bearing into the shop with you to get the size right and reinstall the same number.

It's only prone to cracking if you have no idea what the torque spec is.

^Operator is cryptically alluding to the fact that most of those cups are cracked through overtorquing during installation.
The plastic side is meant to receive far less torque than the drive side. Just snug.
But hopefully jj won't need to bother with that.

Looking at the pictures, it looks like the bearings are in an actual carrier / cage, as opposed to loose balls behind a retaining clip. If you don't use caged bearings, I think you normally have to add one extra ball so there isn't too much slop in the ball spacing.

I just had my bottom bracket apart last night, and it looks almost identical to yours except mine had loose balls behind a pressed-in retainer, which I had no luck "carefully" removing (without risking gouging up the outer race or balls). I'm going to try cleaning with degreaser, repacking and reassembling, and if it's still loose / rough, I'm going with a UN54. One thing to note - mine was asymmetrical - the drive side is longer than the non-drive side (this is on an old MTB with a triple, for what it's worth). To maintain adequate clearance / chainline, I would have to go from a 121mm to a 127mm (see this page: https://www.sheldonbrown.com/bbsize.html , section about Japanese bottom bracket spindles).

Those only crack if you over tighten it.