30. How to Overhaul A Bottom Bracket
How to disassemble, re-grease, reassemble and adjust a cup and cone bottom bracket.
Today we’ll learn how to overhaul and re-grease an adjustable bottom bracket. To remove the cranks you’ll need a crank puller, a 17mm open end wrench and a large adjustable wrench. To overhaul the bottom bracket you’ll need a bottom bracket wrench or a pin spanner, a hooked lock ring wrench, and a 36mm wrench. For re-greasing the bearings you’ll need some cleaning solvent and waterproof grease, a rag, a toothbrush and a small container to clean the bearing cages.
Begin by removing the cranks. Watch the cotterless crank removal tutorial for a more detailed procedure. Once the cranks are removed, loosen and remove the lock ring on the non-drive or left side of the bike by turning counter-clockwise. Once the lockring is removed you should be able to easily loosen and un-thread the bearing race using either a pin spanner or a bottom bracket wrench.
Now pull the spindle and both bearing cages out of the frame. It’s important to remember which way the spindle came out, as they are directional. The drive side usually has a longer distance from the bearing race to the end of the threads. Wipe off the bearing cages, drop them into the solvent, and let them soak while you use your rag to clean the spindle and both outer bearing races.
Tighten the drive-side bearing race by turning it counter-clockwise with your 36mm wrench. Unless you are replacing the bottom bracket, there is no need to remove it.
Shine a flashlight into your bottom bracket shell to inspect the bearing race for pitting and wear. Inspect your other bearing race and then carefully inspect the spindle. Most wear occurs on the spindle’s bearing races. If you see pitting here you should take it to your local bike shop for a replacement.
Now clean both bearing cages with a toothbrush and solvent, and then set them aside to air-dry. These should also be replaced if they are worn or have bent cages.
Apply a layer of grease on both bearing races and cages. A grease gun makes it easy to squirt grease inside the gaps between the bearings. Then place the bearing cages into both races. The rounded side of the cage should be facing down into the bearing race. Seal them in with another layer of grease.
Now insert the spindle the same way you removed it. Wipe off any excess grease that comes out on the spindle. Grease the threads inside the bottom bracket shell, and then slide the outer race and bearing cage onto the spindle. Thread it on all the way clockwise but don’t tighten it. Again you’ll need to wipe off excess grease.
Thread on the lock ring finger-tight. Before adjusting the bottom bracket, first install the drive-side crank arm and tighten it as shown in the crank installation tutorial. This will help us make a proper adjustment. Now hold the inner race firmly with your wrench or spanner and tighten the lock ring. When properly adjusted the spindle should spin smoothly. If it doesn’t, you’ll have to loosen the lock ring, back off the inner race a little bit, and then tighten it again.
Check for play by placing the crank arm close the frame and pushing and pulling it against the frame. There should be no movement. If it feels loose, you’ll have to loosen the lock ring, tighten the inner race a little bit, and then tighten the lock ring again. When the adjustment is correct, install and tighten the left crank arm and you’re done!
Hi guys. I'm new to these boards. I learned how to fix / maintain my jetski and scooter on message boards so now I'm hoping to do the same with my bikes. I have a mountain bike
This one -
(Cheap bike but I like her)
I know that I need to replace the barrings in my bottom bracket. I want to just replace everything since I have all new parts un... Read more >>
I just want to make the point that I am only 16 and a beginner. My situation is that I have bought a frame and fork from ebay to make into a single speed bike.
I have got into some trouble with identifying the bottom bracket but think that I may have chosen a suitable bottom bracket.
I don't know the model bike, only that it is a Raleigh that I think may be from the 80's. But I have little to go on.
The Bottom Bracket shell is 70mm. But this is the confusing part. I think the internal diameter is 34.5 mm (or around there). I have a bottom bracket cup - SM-BB70 -... Read more >>
lately I've been hearing to a clank sound while pedaling, but on the right pedal. At first, I thought that the pedal was the problem. But yesterday I realized that the issue was that the bottom bracket is loose.
I removed the allen bolt and this is how the bracket looks like. (see attachment)
Do you guys know what tools I need to fix that?
After watching some youtube videos I thought I needed a Crank Puller Remover like this one: Read more >>
I apologise if this has been asked before.
I would like to change the BB on my wife's Mountain bike. At the moment it has cup and caged bearings with a square tapered spindle.
Is it possible to replace it with a cartridge type one.
Neil... Read more >>
First post on the forum, but I've been reading around for the last few months while I built my modified Schwinn OR2 700c electric bike conversion. I've done a little homework, but i'm really looking for a bit of advice before i pull the trigger on part orders:
After some decent overhaul to the stock bike, I am now hearing some clanking sounds when pedaling. I've checked the chain for any tight links and just did a thorough cleaning of the chain to see it that could have been the cause. At this point, i'm convinced its an issue with the BB.
After ... Read more >>
I have a schwinn sidewinder I bought at walmart, and may need to replace the bottom bracket. I believe I will need a crank puller, at the very least, and some sort of specialized tool for the bottom bracket itself (maybe). What do I do to get the correct bottom bracket for my bike?
It's an OK bike and gets me where I want to go.
I am mechanically inclined, and do some of my own auto repair work, but I've never done much for my bike other than replace the innertube.... Read more >>
Hi there ,
Ive been given what I believe to be a peugeot ph8 by my uncle . Ive narrowed the year down to somewhere between 79 and 83 .
The serial number is 0931716 PH8CE 60.
Here are two pictures of what I think is the exact same model except my one has cottered cranks .
Read more >>
Is there a good way of knowing what size of BB your bike takes, without having it at hand, and not having the specs from the manual.
I would like to get the tools and part at the same time to avoid repeat trips to the bike store, if I can help it.... Read more >>
I am in desperate need of some assistance here.
I bought a Shimano Ultegra compact crankset to be fittet on my Specialized SL4 Pro Tarmac - 2012.
I want to replace the bottom bracket as well - but my question is:
Would a Shimano Ultegra BB6700 fit my Specialized bike - or would I need some sort of adapter or something like that?
I seem to be stuck in the BB jungle and does not seem to get the right answers when I google around.
Looking forward to hear from you experts.
Thanks in advance.... Read more >>
I'm thinking of switching out my old Ultegra crankset with an FSA Energy BB30. Will I run into any problems with compatibility? Other than the FSA, my bike would be Ultegra 6700. Thanks!... Read more >>
Hi All -
I'm new to the BicycleTutor Forum and having a hard time finding a replacement for my Chin Haur BB. I have removed the BB from the bike frame and not able to locate the correct BB. I have been to the Sheldon Brown website and I'm unable to understand that busy website. In the process of removing the BB, I broke some teeth off the crankset so I will need a new BB and Crankset.
RFJ6... Read more >>
Is it possible to damage the threads of the bottom bracket shell while undoing the BB?
I'm pretty sure the bike shop would have done it while putting the bike together, but if I can check it's not possible (very unlikely) to damage it while lossening then I'll feel more comfortable complaining til they fix it.
Oggy... Read more >>
Looking at new frames and they all have either BSA or BB68 spec'd for the bottom brackets. Which of these would accomodate an old Shimano UN73 sealed bb unit with English threads? Can't afford new components and a new frame. Thanks.... Read more >>
My bike started recently having a problem where every few hundred meters my pedal arm gets loose and shaky, and I have to stop and tighten again.
I've completely opened and cleaned the bottom bracket and I've replaced the ball bearings (not the cages). The situation has improved, but the pedal still gets loose.
I'm not sure what to try next in order to fix it:
When I replaced the bottom bracket it seemed not too worn out, and only the point where the ball bearings touch on it had lost the paint, and it had signs of fatigue where the crank ... Read more >>
Hopefully someone can identify the wrenches I need:
thanks in advance.
... Read more >>