Weird ol' bottom bracket
 

I got this cheap steel frame bicycle off craigslist, but the bottom bracket is knackered so I need a replacement. The spindle is square tapered, so it fits a standard square tapered crank. The BB shell doesn't have any threads, but the ball bearings roll directly against the BB shell, as indicated in the below photo. The shell width is 68 mm. I saw some BB's online that looked sort of similar but not quite. Help much appreciated! :)

http://bikeforums.net/attachment.php...hmentid=465613http://bikeforums.net/attachment.php...hmentid=465614http://bikeforums.net/attachment.php...hmentid=465615http://bikeforums.net/attachment.php...hmentid=465616

Unless the races are truly horrible, you may end up cleaning it up, maybe replacing the balls, using an abrasive pad to clean up the races
and reassembling. The bearing cages are not needed, just convenient to assembly. There are replacement BB for threadless BB housing
that rely on compression, but these assume a certain diameter in the housing, so spacers maybe needed to make them work.

Just a brief google shows this example of such a BB: Mavic Bottom Bracket - Bicycle Parts at discount prices / the Buyer's Guide / Bicycle Parts at their finest! / Professional Bicycle Source / Bike Pro
Availability is another matter, but such do exist.

Yeah, both races are seriously bent. Might I replace them with something like this? (I assume the races are the rings holding the bearing balls, right?)
http://bikeforums.net/attachment.php...hmentid=465619

No, the photo above is of a bearing cage/retainer.The retainer can be straightened - it's only there to ease assembly - but is best replaced anyway. The races are more commonly called BB cups, and are what the balls are sitting on in your 3rd photo. The cups are not part of the BB shell but rather are a press fit - easily removed and installed. The BB shown is a variation of a Thompson/Thun BB. What you need to do is to inspect the cups as well as the cones (name should allow you to identify them) for pitting, especially as it appears the right cup may be pitted.

If they are indeed damaged your best option if the bike is worth it is to get a full replacement. See if a local shop can order a replacement (take in the old parts) or Google "Thompson BB set" or similar (add . You need to make sure it is for square taper and the correct BB width, especially as many of the sources are from overseas.

Also called bearing retainer. You can find new ones, or just use loose bearings instead. Use the grease to hold them in place while you assemble it. You'll need 2-3 more bearings without the retainer. Something like "tight fit minus 1" to calculate how many loose bearings.

Great, that helps me a lot. Then it is the bearing cage/retainers that are bent. I might get away with just getting bearing cages :)

"Might get away with it" yes, but if the cups are badly pitted you will quickly wear out the balls and will have a hard time adjusting the BB. Considering you are in Europe a local shop may have the complete bb or can order it for you. Punch out the cups and take the whole shot in for advice.

walk into your friendly local bike shop with all those parts in a bag, they will match the retainer and ball size an hand you new parts .

Thun BB's considering where you write from they are not weird at all ..