loose ball BB assembly
 

I am about to put together my first loose ball BB and don't really know what steps or what the easiest way to assemble is. It is an older Miche crankset with an offset spindle 115.5mm. Though I haven't read a lot of good about miche cranks, it's what I have to use. I also thought it may not be bad to use a cartridge type campy centaur BB if I can't get the loose ball set up right. I looked for a video on the internet, but didn't find anything very useful. I am most concerned with adjustment and amount of grease to initially put in there. I know these are rudimentary questions, but I need to learn the basics and I don't want to mess it up. As always thanks in advance.

Tim

You first install the drive side fixed cup and get it TIGHT. Recommendations for the installation torque vary from 360 to 600 inch-pounds which a lot. If it's an English or Swiss threaded bottom bracket (left hand threaded for the drive side cup), tight is important. If it's French or Italian (right hand threaded drive side cup) tight is essential. You should apply a heavy bead of grease around the ball race inside the cup and place the balls in it first using the grease to keep them in place. You can install the balls after the fixed cup is in place but it's a lot more awkward as you have to to reach through the bb shell. I use long tweezers if i have to do it that way.

Then insert spindle, adding a layer of grease to it's races first followed by threading in the adjustable cup with it's bearing balls also bedded in a heavy bead of grease. Finally, tighten the adjustable cup until the play in the spindle just disappears and then thread on the lock ring and tighten it while holding the adjustable cup from turning. You may need to make the final play adjustment a few times to get it right. There should be no play but no binding.

As to the amount of grease, I use a lot. I bed the balls in a heavy bead and then add another bead of grease to completely cover them before installing the cups and spindle. It may be overkill but does no harm and gives the best protection from dirt and water. A plastic sleeve can be added to the inside of the bb shell before the adjustable cup is installed as extra protection. Your bike shop probably has these if your bottom bracket didn't include one.

Tim- Good for you trying the classic stuff first. You'll learn more!

Is the RH cup in the frame already or not? It doesn't matter but it's easier to load it with grease and balls if it's out. I use my finger to lay in a wedge of grease that goes all the way around the ball track and fills the cup fully from the spindle hole to the outer edge. Then I place each ball (usually 11x1/4") into this ring of grease until the ball touches the ball track. Some grease will be displaced don't worry about this. After all the balls are in the cup, they'll be held there by the grease, run your finger around the balls and smoothen out the grease. If the cup was already in the frame this is done either through the spindle hole or from the LH side. If the cup is yet to be threaded into the frame I do that now. More grease is wiped onto the threads of both the cup and the shell (infact I grease the whole width of the shell and a little bit up each tube as I can reach). Thread the cup into the frame (might be a LH thread direction) and tighten. the cup needs to be very tight and your wrench can easily slip off the cup so consider a method to secure the wrench against the cup. Some will use a wood clamp as mentioned on a recent thread, others use a big nut and bolt with washers run through the cup and shell. Repeate the greasing and ball loading for the LH cup. If there is any inside the shell (between the two cups) shields or sleeves insert it now. Determine which way the axle needs to go in the shell (usually with the long end on the gear side or with the axle's writing able to be read from above if you had Xray vision and were straddling the bike as though you were riding it). Place grease on each ball track, enough to sit a bit higher then the track, maybe about 1/4" high. Slide the axle into the shell trying not to scrape off it's grease. Holding the axle all the way in thread in the LH cup (did you grease it's threads?) Run the LH cup snuggly against the axle, about 4-6 threads should still be outside of the shell (for the lock ring to fit onto). Rotate the axle to confirm smooth spin. if you knocked a ball out of position the rotating will be rough or loose but tight feeling. If so the remome the LH cup and reload the balls and repeate the installing axle and cup. after confirming that all works properly then spin on the lock ring. At this point you shouls see some grease ozzing out of the cups between the cup and axle, this is how you know if you used enough grease. Grease is cheap so don't worry about really loading the Bb up, any "too much" will just get squeezed out or pushed aside. For many people the next step is the hardest one, how to adjust the bearing tension well. What I do is to install the RH crank arm onto the axle (after wiping off any grease, tapered square cranks want to have the axle and crank hole dry of lube) and torque up the retaining nut/bolt (which should be lubed). (This is when i check the chain line and the ring/chainstay clearances). Now I have a lever arm and pendulum. I'll hold the LH (called the adjustible) cup with the proper tool while I tighten the lock ring a bit, just enough to secure it's place and resist any movement whel wiggling the crank arm. Then i grab the crank arm and pull/push it against the frame in a few points around it's rotation. I use the chain stays, the seat tube and the down tube as the points and the objects to pull/push with. If there's a little bit of play or rocking at the crank arm's end this is good, and the arm should swing down to the bottom like a pendulum. If there's no rocking this is bad. If no rocking loosen the lock ring a bit, loosen the LH cup a bit and retighten the ring. I like to start my adjustment process with a loose bearing adjustment using the theory that you can feel loosenness much better then too much tightness. I'll work the lock ring and cup tighter bit by bit untill the looseness/rocking at the arm is JUST gone and the arm still pendulums freely. If there's a bit too much friction to have the arm spin freely it's ok to err on the side of a SLIGHT bit of looseness, but only a very small amout of it. When the "right" bearing adjustment is had then tighten the lock ring down fully. Note here that you are also pulling the LH cup out of the shell by a small amount and the bearing adjustment will often drift a tad looser. So you might have to go back and start the final ring tightenoing with a bit of bearing pre load to get the final adjustment best after full ring tightness. Experienced mechanics can do this adjustment in only a few back and forths, you might need a bunch more... After the bearing adjustment is good then install the LH arm as you did the RH side. After you ride the bike a few times recheck all. the bearing adjustment might have settled in to a different one. The lock ring might need a touch more tightening. The arm retaining nuts might need a slight retightening. And there will be likely some grease coming out that needs cleaning off.

I do pretty much the same thing as Andrew. It's a fairly straightforward process to do, but it's hard to describe without using a lot of words. Good luck! :thumb:

Guys many thanks on the excellent and detailed replies. I am going to try and assemble the BB this afternoon. I think this will help me through the learning process and I will report back what comes of it. Again thanks, you guys are fantastic.

Tim

I should have mentioned it in my first posting (Andrew's was quite a bit more detailed) that Park Tool's web site has many repair tutorials. Here is the one on adjustable cup-and-cone bottom brackets:

http://www.parktool.com/blog/repair-...racket-service

There are plenty of tutorials on line so I'm not going to explain in detail. However, the one difficult issue might be getting the ball count right. The easiest way is to assemble the spindle in either cup in your hand. With everything dry, put the spindle in far enough to close the hole and feed balls under the lip. When you think it's right, drop the spindle down so it pushes the balls into the tracks and turn in and see if you have enough balls with small spaces between (total free space is less than one ball's width).

With dry trial and error assembly you'll quickly know exactly the right number of balls, and cannot screw it up when you assemble the same into the bike.

It's 11 1/4" balls per side 99.9% of the time.

Well there is a snag in the process. One of the cup threads is boogered up and I have to get a thread file.

Sometimes you can reform the thread by running the tip of a screwdriver or scratch awl through the deformed portion. Assuming if you've found the buggered up portion first, of course. It takes a bit of force, but I've done it.

These look pretty bad. Looks like the first and second thread are pretty well smashed together. I'm going to drop it at a friends to see if he can fix it otherwise I will have to find another cup.

If that's the case, it might be worth it to take the frame to the shop to have the threads chased and the BB faced with the proper tools. Chased and faced bottom bracket shells make things much easier when you're working with a loose ball BB.

Also, try not to shoot your eye out...........

Always :thumb:

Anyone happen to have a non drive side italian cup they don't need?

If it's only the first and second thread, and the rest are OK, you can remove them with a bench grinder (slowly, taking care to not overheat them) and still have plenty of threads to support the cups.

+1. There's no need to remove the entire thread all the way around. Just grind away the damaged area, and there'll be plenty of good thread to hold it all together when assembled.

Just happens I gave it to a friend to try and turn the first couple of threads off with a carbide bit on his lathe. He also has a nicer bench grinder than I which is his last resort. I hope to hear back from him soon. If those options don't work I will have to buy a used cup or set so I can get this built. I am getting anxious to finish the bike.

Why do it the hard way? Turning the thread off means setting up the lathe, fixturing and centering the cup, then turning off the damage. If you take it directly to the bench grinder it's about a 30 second job freehand. You're creating clearance (ie doesn't engage anything) so there's no need for any kind of beautiful job.

When you get it back together adjust the bearings with a slight amount of drag. This is preload and required for proper adjustment and bearing life.
http://www.sheldonbrown.com/brandt/bb-adjust.html

I know, but I already dropped it off with him, but had I thought of the bench grinder I would have just done it Friday and I would probably have the BB assembled by today.

Thank you for the link. :thumb:

I hate to bring this thread back, but I ran into a snag and need advice. I have two different bb spindles, one is 115.5 and the other 126mm. The 115.5 is so close to the chain stay I know there are going to be problems. the 126 seems to give me less than ideal chain alignment and shifting is not smooth and I think it lends to a pretty noisy drive train. Are there spacers made to give me a few more mm on the drive side to allow more clearance from the chain stay? Looking at my campy crank bianchi there seems to be a good 5+mm of space. On this new build I would cal it maybe 2-3mm. What are my alternatives?

Tim

How close is too close for comfort?

I have bikes with chainring/chainstay clearance of only 1-2mm. It's fine as long as you don't bend the chainrings.

However if another 1-2mm will help you sleep at night, you might be able to put a shim under the right cup, moving everything out that far. The limitation will be that the left cup moves in by the same amount. Whether this is workable depends on the relative fit of the lockring and cup. Many have the cup outboard so moving in is possible, but others are already flush or even inboard and there's not enough available thread to move the cup in.

If you have a co-op in town, you should be able to find a used 118 or 121mm spindle. I don't think spacers will be practicable.

I personally like to run as short of a BB as possible -- this gives the narrowest Q-factor, and has me favoring the larger chainring(s) for a particular gearing. Like FBinNY, some of my bikes have very little clearance between the cranks/rings and the chainstays. :thumb: