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Permalink Reply by Far'arned Retrogrumpalunkus #63 on March 23, 2012 at 3:08am

It's easiest to just clean up what you have and put in new loose bearings (probably eleven 1/4" balls on each side) and new grease.   Often the old spindle and cups are fine -just really, REALLY dirty and backed-on grease.

But if you want to put in a new bottom bracket you have a lot more choices and decisions to make.  

If you want/need square taper to match a NEW crank you have and what you had before was something different then it can get sort of sticky.  There are two different square-taper standards.  ISO and JIS.  Sometimes they play nice together and sometimes NOT SO MUCH.   Trying to get the right size is hard enough as the crank itself has to be fitted to the right length spindle to get the chainrings in the right place.  Since there is a taper to the square this meaurement is not so simple.  Mixing ISO and JIS parts makes this sort of a voodoo trail & error science.

Then you have to decide if you want to go with a sealed or an axle and cup arrangement.   The cartridge units are convenient and easy to install but often will not be as smooth as an axle & cup type unless you spend big bucks -and they can get pretty expensive depending on how weird they are.  Did I mention that getting the chainline right can be a trial & error thing?  Do you want to buy 2-3 different ones chasing down that elusive correct Q-factor? (spacing)

Then you need to know what size your bottom bracket shell is -there are a few common ones but most common is 68mm.  Then you need to know what thread standard  you have.  Could be English, Italian, etc. 

Looking at that picture  you might want to have the threads chased and faced by a bike shop.  That'll cost you about $20-50 depending on the shop.  It'll make things a lot easier though.  The shop will be able to identify the thread and shell type and size and point you at bottom bracket options.  If you bring them the crankset you want to use they can do all the math for you and if they mess it up they won't charge you 2-3 times for it.  

If you don't know what you are doing and don't have a guru friend who can walk you through this step this might be the best idea.  If you are buying a BB at your LBS then the expertise to get you the right BB will be included -and maybe they will even throw in a chase & face in the deal.  I recommend this approach.  If it's a good shop and they are not busy you could maybe get the whole thing done (Bottom bracket sized, installed) for about $50 or so.

But the easiest/cheapest thing to do would be to buy 22 new ball bearings, clean up what came with the frame and just re-use it -especially if it is matched to the crank already as it will be the size you want. If you have a different crank in mind then all bets are off on that front. 

Good luck with the project.

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Permalink Reply by Doug Haynes on March 23, 2012 at 3:10am

You should be able to to just put any square tapper JIS bottom bracket in there as long as you get the correct width for your crank. 

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on March 23, 2012 at 3:22am

Here are a few links that might help.

Chainline

Bottom Bracket Taper

Bottom Bracket types/standards

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Permalink Reply by Davo on March 23, 2012 at 3:31am

Thanks for the info. I believe that the bottom bracket is english threadded and of the JIS style. I would prefer to not use loose ball bearings because it seems like more work than the ball bearing rings. It looks like I might be going the axle cup route. I'm definatly not planning on speading tons of money for this build and it is a learning process for me. The main thing that I'm taking from you guys is that I should choose my crank first then get a bottom bracket to fit it properly. This is something that I'll have to look into more as I do want a new crank. Thanks for pointing me in the right direction.

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on March 23, 2012 at 4:20am

Oh, you want to just use bearing cages like this?

Loose balls are not hard at all to install.  You basically "glue" in the balls using the grease.  They stick right there.  Put a dab of grease on the spindle on the drive side, glue 11 balls around it on the race (the shiny ring) and insert it into the fixed cup from the non-drive side.  Before you do that glue in 11 balls with grease into the adjustable cup and have that ready to go.  Thread it onto the spindle after you have it pushed into the shell like I said above.

It's that easy.

The spindle saves a MINIMAL amount of work and is used by bicycle factories doing a thousand of them a day to keep labor costs 2% lower.  Using the cage makes for fewer balls and saves a gram of weght -the cage is lighter than the two balls not used.  But using more balls makes for a longer-lasting smoother BB.  Plus the cages can get messed up and do some serious damage to the BB if they get out of adjustment or the grease dries up.  

I've pulled out a number of them that looked like this -or WORSE:

I almost never use a caged bearing for anything but the main bearing for Sturmey-Archer 3-speed  hubs.   It's a PITA to use loose bearings in those but I've done it.  I'd rather use the cages as it just works better in this one instance.  For a bottom bracket loose bearings are not a serious issue -but if you want to use caged bearings you can probably just get those from your LBS for a couple of bucks. 

For a headset I will use either loose or the caged if it is a new headset and they came with the bearings.  Some headsets are tougher to get the bearings in the right place and use many more & smaller bearings.  But for a BB 11 loose 1/4" bearing balls are a snap.  I've often thrown away the caged bearings that came with new BB's because they are cheesy IMHO.

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Permalink Reply by Davo on March 23, 2012 at 8:07am

Thanks for the tip. Maybe ill buy new bearings and use the old bb to get some practice doing it that way

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on March 23, 2012 at 8:34am

If you go to a bike shop they will charge you between a nickle and a dime per bearing if you buy them one at a time.  I know Boulevard will do this.  That's 22 bearings -not a hardhip!

As for grease, I tend to use a lot of the waterproof trailer grease you buy in the 16oz tub from just about any hardware store or auto parts warehouse for about $5-6.    That tub is a lifetime supply for most home mechanics although I go trough a couple of those a year. 

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Permalink Reply by Barry Niel Stuart on March 23, 2012 at 10:06am

I just noticed that there was a crack between the top tube and the seat tube of the frame you wish to use.  Are you sure you want to build it up given the crack at that joint?  I'd be concerned about its structural integrity.

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on March 23, 2012 at 10:12am

I do not think this is a crack.  I believe that's just a little bit of the red & yellow paint in the corner of the seat tube next to weld that didn't get completely removed as it was so hard to get to.

Barry Niel Stuart said:

I just noticed that there was a crack between the top tube and the seat tube of the frame you wish to use.  Are you sure you want to build it up given the crack at that joint?  I'd be concerned about its structural integrity.

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Permalink Reply by Davo on April 9, 2012 at 11:06am

James,

Thanks for the tips on the BB concerning the ball bearings. Upon further inspection of the BB I found this:

 

 At First I thought it was some part of the BB (like a washer or something) but when I was cleaning it they popped out. I'll definately put loose ball bearings in now. Here is another question though. The housing around the spindle (where the ball bearings are held to the inside) is plastic. What is your feeling on this?

 

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on April 9, 2012 at 11:21am

That is sort of bizarre, but it looks to me like a variation on the BB condom that some manufacturers put into their bottom brackets to protect the bearings and the grease from getting contaminated.  

It can be re-used if it is cleaned out and then carefully slipped back in over the bearings as you assemble it.  You can fill it with more grease too which will only serve to make the BB last longer and be less prone to drying out over time although it will add more weight.  

Most of the BB "condoms" I've encountered have an accordion style corrugation that can account for variations in overall length although this one seems to be made to be the exact length of the bike in question.  

My advice is to put it together with loose bearings and see how well it runs and if you can get the bearings loaded to enough pre-load that it is tight while still spinning freely and smoothly.  If your races are in good shape and the spindle isn't pitted everything should spin freely and easily on the new balls and grease if you put it together right.  It should be almost like butter.  

If not, you are not out anything but a little bit of grease to pull it apart and try again.  That's how you learn. The hardest part is having the right wrenches to hold the lockring and the adjustable cup and getting the feel for just how tight to make them to get any play out of the spindle while still allowing it to spin.  It's not a jet turbine so it's not exactly a piece of high-tech.  Spindle & ball bottom brackets have been around since the steam era.  They aren't really all that hard to work on. 

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