trayraynor

I'm overhaulin' the bottom brackets on my mountain tandem. Its been running Shimano Deore DX since it was built in 1992. Looks like the spindles are toast (pitted, brinelled, false- brinelled?) see photos. After reading all the excellent posts on bottom brackets, what causes wear, etc. I've concluded that these spindles, if not the entire bottom brackets, must be replaced.

Trying to stick within my budget, I'd prefer to replace the spindles, but that no longer seems likely as I've searched online for replacement square tapered spindles: Shimano D-3NL 68 x 122.5 and found nothing, several seem to come close, but nothing with EXACT dimensions.

According to Sheldon Brown's site, a Deore DX MT 60 BB, or a Deore LX M550 BB should do just fine. However, I can't seem to find anything new that comes close.

What are my options? Do I need to replace the entire front end drive train including BB's and cranks? Is there a possibility of having these spindles machined, and replacing the bearings with smaller diameter to match the machined spindle?

Any leads to replacement BB's, or advice on the next steps are appreciated.

FBinNY 

That's classic wear. It could have been speeded up or made worse by poor lubrication, corrosion, or excessive preload. Spindle bearing surfaces are harder than the layer below, so once the wear breaks through the skin the process accelerates and it ends up looking like yours.

If you're willing to accept a lower quality but still very passable CrMo spindle, I have an assortment of SRs one of which should match.

If interested, send me the right, middle, left, dimensions and overall length (to check the math). I'll check and let you know. If I have one that'll fir, cost would be $11.50 including postage.

bikeman715

If all else fail you can always replace with a seal BB from shimano ,just get the right length.

ultraman6970

To make you feel fine about picking the right length, a sealed BB 1 or 2 mms smaller or longer wont make any difference. In a matter of fact if you have like 5 mm before the crankset or chaining touch the chainstay, u can pick a shorter one. I went all the way down from 127 to like 118, even the shifting improved. The other thing is that 5 mm difference in the lenght of a BB for example looks like a lot but technically are 2.5 mms at each side, that actually is not that much.

Good luck.

davidad

https://www.biketoolsetc.com/index.cg.../Taper-Spindle

HillRider

Shimano's sealed cartridge square taper bottom brackets are very good and should be available in a wide variety of lengths up to 127 mm if you look around. Well worth using them to replacing a hard to match cup-and-cone bbs.

The Sun Race and Tange bbs davidad referenced are also usable and functional.

rccardr 

I also have a handful of wider asymmetrical cup-n-cone spindles in my box in good condition, ranging from 118 to 127. You're welcome to any of them for the cost of postage.

trayraynor

Here are the dimensions of the current spindles

ultraman6970

U can use a simetric one w/o any problem, sealed 122's are available

Mr IGH

Yes, but he should add 2~3mm to the final dimension to compensate of the asymeteric spindle. A 127 should work.

relyt

I'll just quote this for emphasis because it is absolutely correct. Just buy a new sealed BB with a similar spindle length. I would go for a slightly longer one rather than a slightly shorter one if there is any chance the chainrings would touch the chainstays.

trayraynor

I'm interested in the 127 mm length; do you have two?

rccardr 

Went through my remaining spindles and the closest I have (no 127's left) is a 3S- that's 125mm end to end, same 35/37mm asymmetrical ends, but perhaps not the same size between the bearing races- do tandems use an unusual size there? Not a tandem guy myself...

trayraynor

Coming up empty with replacement spindles I made a trip to my LBS and picked up a pair of Shimano UN 54 square tapered BB's. The package indicates that these BB's are "E-Type" and I checked my front derailleur which is a Shimano M650 FD, not an E-Type, as it has a 1-1/4" clamp mount. Am I missing something if I use these new BB's; are they incompatible with the FD?

Amesja

From the picture it's very hard to tell but it doesn't really look that bad to me. I've seen much worse put back into operation. I don't see any pitting or brinneling in the channel at all in those pics.

Yes, there is some wear in there but the bearing channel looks good for the most part. There are some spoils to the outside where material has migrated to the sides that look ugly but it looks like it is outside of the edges of where the balls actually touch. From that picture it looks like there is still plenty of life left in that spindle(s). I'd personally just rebuild with new balls and grease and keep running them. What's the worst that can happen -ruin them and/or the cups???

If a rebuild yields smooth operation then let them run until they get much worse than that. You aren't going to hurt the BB shell in any case. This is a bicycle not a high RPM engine. You aren't going to get a seizure which will spin the races and ruin the BB threads or damage anything outside of the bearings themselves.

When it finally does give up the ghost (there will be plenty of warning) do as others have said and just replace the whole BB with a sealed unit. I think, looking at those pictures, that it is a bit premature for that.

FBinNY 

No, you're probably not missing anything, except that possible the spindle distance between the bearing races is slightly greater than normal to allow for the thickness of the FD's bottom bracket mounting plate. Compare it to your existing spindle and if the bearing races are a bit farther apart, either add a spacer under the right cup, or live with the left side cup hanging a bit.

BTW- it's also possible that the spindle is 100% right as is, and the use of E-type in FD's and spindles is unrelated, and reflects a shortage of letters available so some get reused in different contexts.

ultraman6970

Agree with FBinNY... probably what u have it works fine, just adjust the FD as any other FD.

trayraynor

Thanks all for weighing in on this; I found a set of new bearings and will install the old spindles this weekend. I'll get back with a post install reply.

Amesja

Personally, I'd have just used loose balls. They are much easier to source and more balls are almost always better -especially on iffy races. Most LBS's will sell them for you for about a nickel a ball or you can buy a 144-pack from Amazon for $5-6 in any size you want.

Using the correct ball-retainer for your spindle will be just fine if you have them now. Keep an eye on them after you get it back together and are riding the bike for any changes in tension. I suspect you'll get decent service life out of this rebuild. If they become unstable (need tightening up often) then that is a warning sign that they need to be serviced again/soon.

trayraynor

After debating using the retainer clips or not, I elected to stay with the retainers. I played around with the fit, retainer facing the cup, retainer facing the cone until the unit fit right (retainer facing the cup, balls facing the cone)... after experimenting with how much to load, it seems like their just about right. I'll attach the cranks and re-check, but so far so good. Thanks for all the input!

Amesja

I've never had luck with bearing tension on a bare axle or spindle. Once I put a wheel on the frame or the cranks on the spindle I am not happy with how the initial tensioning was. Same with the headset.

The only way I like is to put the bearing item on the bike and tension on the frame with some decent leverage to check for any slop. I merely adjust to the point where I can feel no slop and no tighter. Without something bolted onto the bearing axle it is very difficult to reliably feel for slop -for me at least.

Recently I found the only way I can get Sturmey-Archer hub bearing tension right is to do them on the bike. Those MUST have a little bit of slop or they will bind and drag the pedals when coasting. Knowing exactly how much that slop needs to be is just guesswork for me right now. I just play with it until it is just right. Even so, if you get it just barely loose enough when you set the cones so that it works but without the left side axle nut tightened when you go to tighten that it makes juts enough difference that it'll start dragging again when you tighten it. If it was just a tiny bit too close just that last axle nut will make enough difference that it'll start binding again.

With the BB my best bet is to just get it close and put the cranks on and then worry about it when I can put both hands on both pedals and use a lot more force to feel for any slop in the bearings. I tighten it just enough so that no slop can be felt and quit right there. BB's usually take me 3-4 attempts before I get it where I like it.

FBinNY 

Years ago, I had the good fortune to be trained on SA maintenance at the factory in Nottingham. There I learned what I now call the Goldilocks Rule for adjusting SA hubs. Final adjustment is done in the frame with the right side tight and the left nut firm. Rim is felt for play. No play = too tight, obvious play = too loose, maybe a trace of play, but not sure = just right.

BBs are always adjusted with the right crank mounted. The rule here is zero play detectable with the fight arm back at the chainstay for reference. Or tap on the arm or spindle and it shouldn't be felt on the opposite side. BBs operate under decent load, and a hair tight is better than a hair loose, so aim for the zero point and err high.

Amesja

That is exactly the method I re-invented. It's the only way it would work. I would just finger tight the left side nut and test to see if the pedals dragged after each attempt. If they passed that test then I'd tighten the left nut down and try again. If they still didn't drag then it was "just right" -if not I'd loosen the left side nut again and then readjust the cone a tiny bit looser and set it against the locknut again. Finger-tight the axle nut and re-test. I just kept doing this until it worked. The more I worked on the SA hubs I had the quicker I zeroed in on the Goldilocks Point.

The Video I was watching on SA hub maintenance had the guy showing how to tension it right on the vise. That just did not work for me at all and it always had to be re-tensioned on the bike. I couldn't imagine working on a bare wheel for someone else without the whole bike as I am sure I wouldn't be able to get it right and the poor sod would have to deal with it on his own when he got the wheel back. Perhaps if I ever help someone out in the area by working on their hub I'll have to use one of my own bikes to test it on.

BB's are easy-peasy in comparison.

FBinNY 

Pedal drag is the wrong indicator. It can be caused simply by the viscosity of the lubricants. The object is to eliminate bearing play, because, surprisingly, slightly loose bearings wear faster than slightly tight ones. Also detectable play at the rim worsens bike handling. Whether you feel the rim with the axle in a vise, or in the frame doesn't matter, but I prefer doing it in the frame because slightly non parallel dropouts can bow the axle effectively tightening any adjustment.