How to Overhaul a Bottom Bracket
How to disassemble, re-grease, reassemble and adjust a cup and cone bottom bracket.
Video updates
- 02:22 - IMPORTANT: Apply a thin layer of grease to the threads before inserting into the frame.
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.
Disassemble
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.
Inspect
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.
Clean
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.
Grease
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.
Reassemble
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.
Adjust
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!
Related Links
Recommended Tools
- Park Tool Park HCW-11 Adjustable Cup Wrench
- Hozan C-205 Lockring Tool
- Super Lube White Grease Tube
- Finish Line Grease Gun
- Shimano TL-FC10 Crank Extractor
- Park Tool CCW-5 Crank Wrench
Categories
Discuss this topic in the Bicycle Repairs and Mechanics Forum
Trek 720 (1997) Drive Train (Crank & Deraileur) Replacement
Lastest post 1 day agoMy 1997 Trek 720 Multitrack was diagnosed at the local bike shop that the crankset, cassette, and chain need to be replaced. I think the front derailer also needs replacement. I ride for fitness so I do not care that much about the weight penalty using this older & heaver bike. I checked my online cycling log that tracks my workouts and it was says there is over 5,000 miles over the last...
Read moreSchwinn 3rd Avenue 700C hybrid
Lastest post 5 days agoThe bike, new, was $199 from an Amazon dealer, and it came with a load of great reviews and very few negative ones. That should be a warning to anyone looking for a new bike; the shills are out there. If anyone buys one with the idea of putting it together and going for a ride, they would be disappointed. Walmart bikes are better. Seriously! I knew that it would need some work because you do...
Read moreSquare-Taper BB 68 (1.37 24T) Crank-Arm Fixing Nuts (not bolts) Comes Loose
Lastest post 5 days agoNew to forum, just signed-up, after reading an entry about constantly loosening crank-arm fixing BOLTS. In my case, my original BB, uses crank-arm fixing NUTS (original equipment, not jury-rigged), instead of BOLTS. I’m “dating” myself, but I’ve had this bike since new. I’m constantly re-tightening the nuts, every other ride, or worse, at times after a long ride. I have had difficult...
Read moreLoose seat stem housing on Trek Madone 9.2
Lastest post 1 week agoAnyone know how to remove the plastic cover at the base of the seat stem housing on a Trek Madone 9.2? The housing piece for the seat stem wobbles a little and I'd iike to tighten it. Assuming there's a screw underneath the covers. IMG_2660.jpg (Size: 51.17 KB / Downloads: 109) IMG_2659.jpg (Size: 44.51 KB / Downloads: 109) Thanks! Bill...
Read more1962 Varsity - Move Stem Shifters Ok?
Lastest post 1 week agovarsity.jpg (Size: 152.97 KB / Downloads: 202) varsity2.jpg (Size: 77.64 KB / Downloads: 203) Hi. This is my first post. I have a 1962 Varsity that I've enjoyed riding since I was 10. I'm in my 60's now and just want to putz around the neighborhood. In order to make the bike more comfortable I put a super big seat on it and 12" high handlebars. It's my Lazy-Boy on w...
Read moreWhat’s the name of this bottom bracket ?
Lastest post 2 weeks agoI need to know what bottom bracket I have but I can fin a number or code on it to read it. Any experts in here, this is my first post. 006BA1F3-FE4D-4D22-85F0-095E72284B3D.jpeg (Size: 46.12 KB / Downloads: 60) ...
Read moreCustom Frame Headtube and Fork
Lastest post 2 weeks agoG’day, I have a couple of questions. I want to install Fox 40 29” on a new custom made frame. Frame not made yet. The headtube will be straight headtube 44mm round 120mm or 135mm in length. What length would be best? I’m looking at zs44/28.6 zs44/30 headset. Would this be the right headset for the tube and fork? Also any tips on how to installing the fork and headset? Does the uppe...
Read moreCan't adjust angle on adjustable quill stem
Lastest post 2 weeks agoI have what I take to be an adjustable quill stem, after some research. I had a bit of an incident in which a wheel temporarily became slightly loose, and I think the angle of the stem somehow moved closer to 180. The handlebars aren't at the right angle. Anyway, I've unscrewed the angle adjusting bolt, but I can't get this thing to budge. What do I do?...
Read moreRefitting a sturney archer wheel
Lastest post 2 weeks agoI am having difficulty refitting a sturney archer 3 speed wheel. The chain on the indicator bar is coming out at the wrong angle by about 90 degrees. I have clearly reassembled incorrectly but I cannot see a way of assembling with the axial rotated by 90 degrees. Suggestions gratefully received. [attachment=1236] 71DD7E3C-8E11-4410-8239-13AB8963A4D3.jpeg (Size: 71.18 KB / Down...
Read moreIs Dunlop valve almost the same as Presta?
Lastest post 3 weeks agoHi everyone. First post, posting from a phone while on a week-long bike tour. I forgot to pack a spare mountain bike tube [/w presta valve] and there are not many bike shops around, but we managed to pass by one in a remote area. Surprisingly, they only got Dunlop and Auto valve, no sign of Presta inthe necessary size. Was it a gamble to take Dunlop? Does it usually fit with the same rims as Prest...
Read moreBrake wire
Lastest post 4 weeks agoTook my bike out after a couple of years only to remember that my left brake broke off while using it last and there is an unusual cable hanging from my bike that gets in the way sometimes, is it okay for me to cut it off? Will it affect the right brake?...
Read moreNordicTrack U300 Knocking
Lastest post 4 weeks agoI'm hoping someone can help me figure out what is causing the knocking sound on my NordicTrack U300 stationary bike. Any help would be greatly appreciated! Here is a video of the knocking sound: https://1drv.ms/v/s!AnBkAt1Ty5oGiGDlEifMjPDihGr7?e=08qsm9...
Read moreHorrendous noises when pedalling
Lastest post 4 weeks agoI have just started hearing horrendous noises when pedalling my 7 week old Trek Powerfly 4 ebike. The sound is worse than clicking and clunking and I can’t tell exactly where it is coming from. So have uploaded a video here: https://youtu.be/G3X2tLHk4Bk. Has anyone had similar or know what if could be? I’ve not heard these types of noises before....
Read moreGear shift is stuck!
Lastest post 4 weeks agoOn both my bike handles, the gear shifts are stuck and I can’t move them. They’re currently stuck on gear 5 now (the highest). How do I fix it without needing a new gear shift?...
Read moreHelp with filling up hydraulic brake lever without bleed kit
Lastest post 1 month agoI bought a can of mineral oil from motorex and it came in 250ml aluminium can with big cap, and I need to fill my brake lever with that oil but I don't have syringe or bleed kit. How could I fill it up without syringe or bleed kit and tips? Anything similar to syringe that would work? 54e2f371.jpg (Size: 152.52 KB / Downloads: 54) ...
Read more
