jazzgeek79

I commute on a 1988 Schwinn Voyageur. I think the bottom bracket is shot. If I pull the drive side to the chain stay I can see the axle move and see the non drive side crank move as well. The non drive side crank bolt was very loose, but tightening it didn't seem to help. According to the scans on Waterford's site the bike came with a "Shimano Sealed Bottom a Bracket". If that bracket is still in the frame does anyone know if I need a new bb or can I replace just the sealed bearings. I'd like to know before I open up the bike because once the cranks off I'm down my main from of transportation. I'm planning on doing the repair at the newly formed local coop but they are only open one night a week and after the shops close so I'd like to walk in with the parts I need.

FBinNY 

Most (all?) of Shimano's cartridge BBs are not designed to be adjusted or rebuilt. You simply replace the cartridge when it's shot, and I figure you probably got good value pout of it over the last 25 years.

The definitive test of a worn BB is if you can wiggle one crank and have to movement translate through the BB to the other, as you're does. If one crank moves and the other doesn't, then the crank is loose on the spindle. From your description you had both conditions, and have addressed one.

demoncyclist

You will need to know the spindle length of the one that you have in order to source a suitable replacement.

Andrew R Stewart 

With that age bike you could very well have a "classic" cup and cone BB (still possibly sealed, just maybe not a cartridge bearinged unit). If so it could be removed, cleaned up, examined for wear/pitting and reinstalled if still in good shape. If not in good shape the replacement BB needs to have the same drive side spindle length (or more accurately the chain rings need to sit an acceptable distance from the frame's center). The original spindle should not be assumed to be a symmetrical style. Meaning that measuring it's overall length might not give you the drive side length to position the chain rings the same (or reasonably close to the same) as the original. With the original spindle in hand the drive and non drive sides can be compared and the replacement BB can then be determined.

I have measured spindles while still in the shell only to find that the replacement didn't position the rings properly, because the original spindle was not symmetrical (mirrored L to R). Most all modern cartridge (as in factory assembled cup, bearings and spindle) BB units are. Andy.

cny-bikeman

It's quite easy to tell which type you have - cup and cone on the left, cartridge on the right. As noted the former can be overhauled, though the right spindle may be difficult to determine before disassembly, and difficult to find as well. The cartridge should be replaced and should not be hard to find. Both take specialized tools to remove and install (shown in pic. A shop is likely going to be able to determine what cartridge you need, perhaps what cup/cone type. Very hard from here to assure you of the right parts, impossible to tell which you do or don't need for the cup/cone.

jazzgeek79

I have no idea if the bb is original or not. I am at least the third owner of the bike. If it is and asymetric could I measure the spindle on the bike and order the measured size and a size up and then return the one I didn't need? Andrew when you discovered your asymetrical BB was there a difference of more than one overall size. For example measuring 110, but needing 113 for example.

I just bought a project bike to have two commuters so I wouldn't have this issue and of course this happens before the project bike is finished! Go figure.

jazzgeek79

mine has a lock ring like the one on the left

fietsbob

well there you go.. it's a loose ball BB, time for a new one..

the Shimano UN series BB are fit and forget .
if it needs replacement it goes in the trash , and you get a new one.

they're cheap enough.

jazzgeek79

Now I just need to figure out spindle length

fietsbob

Take it out ,cups and all take it to a bike shop , show them and they will help get the appropriate substitute.

or just go with bike to the shop, you dont need 2 sets of tools then ,

1 just to remove things that wont be replaced is not that good a bargain..
the spline installation tool with a 1/2" square drive will work with ratchet or torque wrenches

Andrew R Stewart 

One trick I've used (having learned the hard way) is to measure the old spindle from the shell's center line to the end of the RH side. This is 1/2 the length of a symmetrical spindled cartridge one. So if the old spindle is about 60mm from RH end to shell center then a 122 new cartridge BB would be the first I'd try.

Another trick is before you pull off the RH crank arm gage the amount of room between the inner ring and the chain stay. This is to have a handle on how much shorter the replacement spindle might be before the ring would contact the chain stay.

All of this is filtered by the actual amount that the crank arm pulls onto the spindle. This amount is not a fixed amount and can change a small amount over time as the crank arm tapered hole wears and/or the arm is retightened. We are not dealing with exact numbers here. Andy.

jazzgeek79

I'm going to do it at the local coop at the next open shop provided they have the tools. Can I ride it until I fix it. Say in the next week or so?

Andrew thanks for the info. I think I can make that work. I have experience changing out chain rings so I feel comfortable doing that on my own. I just don't want to mess with the BB until I'm at the Coop with at least one person that knows what they're doing better then me,

speedy25

Being as loose as you describe it can cause damage. You wont know how badly until you take it apart. If you get real lucky a set of new ball bearings will make it work well again. Otherwise you wil have to get the rest of the parts too.

Good luck! Have fun with your learning experience.

-SP

jazzgeek79

So I'm going to replace the BB. Even in the unlikely event that I can overhaul the current BB I've decided I can afford the new BB more than I can afford to have my bike off line for a day or two while I try to source bearings once the old BB is removed. I've done some research on my crankset. It is the shimano bio pace fc-b124 as near as I can tell. The version with 28-44-50 teeth rings. The inside of the drive side crank is stamped with this model number. Apparently it was an economy version of a deore crankset made between 86-88. I found a scan of the shimano parts catalogue from 87 that shows specs EXCEPT for the bottom bracket size. It does list the size for the higher end bio pace cranks. Are they likely to be the same? Anyone have this set and happen to know the correct spindle length?

jazzgeek79

https://www..disraeligears.co.uk/Site...9_scan_19.html

Oh I meant to post a link to the scan. Here it is

jazzgeek79

Here is a link to the scan.

https://www.disraeligears.co.uk/Site/...9_scan_19.html

fietsbob

web pictures is still avoiding just taking the BB out and gathering the dimension data..

had a 68-118 loose ball in the 80's
in a different bike with an XT M730 crank,


You still have yet, to take it out, and apart, to see the bearing races..

jazzgeek79

Yes I am trying to avoid it. My bike coop, which has the tools I don't, is only open one night from 6-8, after bike shops close. If I take it out to measure then I will be without a bike for up to a week. If I just take it to a shop I'll be without my bike for at least a day or two. I need my bike to commute to work and school. So the one week hiatus isn't an option. A day or two is less then ideal, and also at least $25 more expensive.

ThermionicScott 

Budget for a new NDS crank as well -- it's probably toast from being ridden while loose.

Homebrew01

It may be as simple as a bit loose. 15 minutes to open it, add some grease and put back together. That may be good enough. Not every bike needs perfection.

BB bearings come in just a couple standard sizes, so maybe the coop has some if they are needed. If it has a ball retainer that is damaged, you can toss the retainer and use loose ball bearings instead. You will need 1 or 2 more than originally came with the retainer.