robertj298 

I am about to start tearing apart my bottom bracket on my 1985 Specialized Sequoia and was wondering what
bearings to get.I know I need to get the same size but is there a certain material or brand I should look for?

Unca_Sam

There's likely a thread on this already.
Who manufactured your bottom bracket?

Unca_Sam

I won't school you, you can learn from my teachers:
Sheldon Brown

Calvin Jones

LV2TNDM

This all depends on what you mean...

If you want to utilize the bottom bracket you have and want to simply overhaul the bearing, then you need 1/4" grade 25 (or better) replacement ball bearings and good waterproof grease. Do not reuse old ball bearings if you can avoid it. Plus, the old ones were probably grade 100 or worse, so the higher grade replacements will result in longer life and smoother operation.

This, however, assumes the spindle bearing surface is not pitted (or worse, the cups). Given its age, I'd be surprised if it weren't - unless you've taken really good care of it.

And IF you plan to utilize this type of bearing (considered "non-cartridge" BB), you may want to have the BB shell faces milled flat and parallel. Chasing threads isn't a bad idea either, however, a small round wire brush on a drill will clean up the BB threads beautifully.

If you simply want a durable replacement bearing and don't want to deal with potentially expensive frame prep, then just replace it with the appropriate Shimano UN55 BB. Cheap and long-lasting.

To match what you have, you have to get the correct two dimensions: BB shell width (68, 70 or 73mm) and BB spindle length. Taper has to match also, but almost all are JIS, I think. (This has always kinda eluded me, I'm embarrassed to say! See Sheldon Brown, which doesn't even mention Campy... https://www.sheldonbrown.com/bbtaper.html)

Did I help or just confuse you?

robertj298 

Specialized sealed

LV2TNDM

Ha! That's pretty funny you mention "Specialized Sealed" because I just happened to pull the Specialized titanium bottom bracket out of my city bike. Finally decided to retire it after about 20 years. Finicky BB prone to wearing out cartridge bearings prematurely. Sick of clunking & slight chainring wobble. This is the one made by White Industries, branded Specialized. It most certainly isn't the one you have. I replaced mine with the aforementioned UN55, 68 X 122.5.

Thinking of putting it on Ebay. A nice vintage lightweight BB, but not idiot-proof or very durable.

grizzly59

Here are some specs on yer bike:

1985 Specialized Catalog

Get a caliper and take some measurements of the axle length, how far it sticks out of the drive side, and the width of your BB shell, etc. There are probably some codes engraved into the old one. Give us a full report with pictures and someone will be able to point to a modern BB that will work. Some model of a Tange LN-3922 or Shimano UN55 will probably fit. This may be the type of tool you'll need:

https://www.parktool.com/product/bot...ttom%20Bracket

cpach

If you have a cup and cone bottom bracket, the bulk of these used bearing retainers. While I generally like loose bearings, this is one place where bearing retainers really make life easier, and I'd recommend you get a full replacement if this is what you have.

Really though, cartridge BBs last incredibly long, are easy to replace, and are cheap and I would generally always err on replacing with one unless the original is especially high end or collectable.