Seizedpost

What do you think of this bottom bracket cup? It's from my 1986 Schwinn Mirada. I was going to rebuild it with new balls but I'm starting to think the cups may be too far gone. They've got some pitting and galling. The fixed cup looks pretty much the same as the one in this picture.
Incedentally, the balls looked pretty good except for one with a huge gouge.

sonatageek

$25 will get you a smooth Shimano UN-55 cartridge bottom bracket. Of course you have it apart, so why not get the grease and put it back together and see how it is? Worst case you need to take it back apart and replace it.

dsbrantjr

I'd put it back together with new balls (I never re-use them) and new grease and see how it goes.

schlopartist

How is the spindle?

What sonatageek states is what I will probably do; explore getting a cartridge bottom bracket. However, if you are so inclined, you could try to smooth out the rough spots with say #0000 steel wool and some light oil and rebuild it. I would have replacement parts in hand FIRST. I would, however, consider re-greasing the rebuilt bearing assembly every 6-months while in use.

Mine on the other hand "ist kaput, ya?". Bottom Bracket Problem Slideshow by hecktg222 | Photobucket

https://www.bikeforums.net/bicycle-me...build-him.html

Seizedpost

The spindle doesn't seem too bad. I can post pictures of it tomorrow.
I think my spindle is a 124mm. The UN55 is available in 68 x 122.5 and 68 x 127, booth of those seem a little far off.
Schlopartist, yours does look pretty kaput.

CliffordK

I'm not seeing the pits in the photo, but sometimes they are hard to show.

If the choice is to replace or not, then obviously you can't make it any worse with riding.

I did try running my Campy spindle in the lathe with some success. But it was HARD to cut.

Seizedpost

So just to clarify, these are the same material throughout? I won't be removing the remains of a hard coating by polishing the surface?

andr0id

Hard coating? 1986 Schwinn? Not a chance.

If the cups aren't pitted (doesn't look pitted in your photo ) just put in new balls and roll on.

Usually the spindle will pit first and need replacing long before cups.

Flyingblind9

+1. Schwinn rarely used hard coatings on bikes of this vintage and your cups do not seem to be shot, although pictures may be deceiving! As long as the spindle looks good, and a light steel wool polish is applied, you should be ready to put on plenty of satisfying miles!

CliffordK

I'm not sure... pits will make bigger pits, and damage the bearings and wear both the cones and cups.

So, polished should be better.

Since last year, I've started polishing all of my cones before installation. I've got some wheel cones with a few thousand miles that I probably should inspect soon.

Anyway, my opinion is hardened or not, a superficial surface polishing should be an improvement.

Cutting out deep pits may give one a weaker surface. But, if it is already shot, why not give it a try (as long as you don't ruin something like the cups that may have still been good.

It also depends on your replacements. I have no doubt that not all manufactures use the same surface quality standards, so a cheap "generic" may be worse than a restored original.

Retro Grouch 

What kind of clearances did your crank have previously? 122.5 mm is only 1.5 mm less than 124. That's less than 1 mm on each side. If you feel like you don't have that much room, I'd probably be looking at the wider 127 mm anyway.

Seizedpost

I ended up rebuilding it. It felt pretty decent once I had it assembled and adjusted. I replaced the 9 ball cage with 11 brand new loose balls per side as Sheldon Brown recommended. It felt pretty good when I turned it by hand, once I had it adjusted and the lockring tightened.
Clearance is pretty good, I could probably go with the 122.5 mm UN55 if I ever upgrade it.
Here's my thread for this bike:
https://www.bikeforums.net/classic-vi...nn-mirada.html