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
Help! Tool for removing SHIMANO MF-HG20 cogs
Lastest post 6 hours agoHello there, I'm trying to clean my Shimano MF-HG20 freewheel, and want to disassemble the cogs. But I found there is a lock ring that seems need a special tool to remove it. Could you please teach me what the tool's name is? It is in 46mm diameter and has 8 notches on it. The notches are semicircle. SHIMANO MF-HG20-1.jpg (Size: 81.38 KB / Downloads: 23) Thank you....
Read more10 speed derailleur with 9 speed shifters?
Lastest post 11 hours agoMy 9 speed Campagnolo Mirage derailleur broke down & I am looking to replacing it. However, there aren’t any 9 speed Campagnolo (new or second hand) derailleurs available (in the Netherlands. (Well that statement is not fully true, I did find a second hand 9 speed Xenon derailleur, but I got it delivered broken) I can find a new Campagnolo Veloce 10 speed derailleur. Since I have seen 9 spe...
Read moreHow do I know when my pinch brake calipers need to be replaced?
Lastest post 16 hours agoBicycle repair newbie! I've been fighting and fussing with the v-brakes on my wife's bike. (The linear pull variety.) Watching lots of videos, but still can't get it right. Most likely the problem is my clumsiness and ignorance. Those two problems will likely be solved over time and I'm sure I'll eventually get those calipers adjusted correctly. However, if they actually need replacing, how ...
Read moreWater in tube.
Lastest post 17 hours agoI'm fixing up my wife's old bike to sell and when I pulled the tube on the front tire it had water in it. Haven't seen that before. What would cause that and is it a problem I need to take care of? Thanks. John...
Read moreBike Brake Calipers Not Springing Back
Lastest post 20 hours agoMy bike brakes are unfortunately not working because when apply the brake the brakes press to the rim but my right brake pad does not spring back My Bike is a road master granite peak 26 inch wheels and my brakes are aftermarket and the brand is. “I know this might be a caliper issue but I don’t really know how to check that”...
Read moreFork done for? Has slight cut in it
Lastest post 20 hours agoGot this bike sight-unseen from an auction. Only recently found out there was a slight cut in the steerer after taking it apart. Around 1mm deep and is only on one half of the fork, it doesn't contact any of the headset bearings but it is within the headtube. Is this fork compromised? Or still rideable. 20210730_215646.jpg (Size: 22.41 KB / Downloads: 4) 20210730_2...
Read moreCan I fix my Campagnolo Mirage derailleur or does it need replacing?
Lastest post 24 hours agoAs you can see in the picture attached, my derailleur (Campagnolo Mirage 3x9) has a top bit broken off (The thingie that hold the spring in place, if anyone knows a nice name, let me know!). I cannot find any campagnolo mirage derailleur (second hand) online (in the Netherlands). So I have to questions in which I can need your help: 1) Is it possible to just replace that part of the derailleur? I...
Read moreDoes the B limit screw cause grinding in the drivetrain if not set correctly?
Lastest post 2 days agoIt happens only when I’m pushing a big gear up a slight gradient in the saddle. My first thought was the BB needed to be replaced but I took it to the shop and they said it was fine. They thought they fixed the problem with adjusting the b limit but it only helped it maybe a little. It didn’t solve the issue. Would there be any other causes? I have Shimano GRX 810. Happens when the clutch is ...
Read moreWhat to do about scratched carbon fork?
Lastest post 3 days agoHello, cycling lovers! A couple of days ago I had a lesson of riding in a group, which ended with crashed bike =) Fell to the side, so the main impact was absorbed by my shoulder and hand, so I believe no major damage was caused by this crash except some paint removal. So I'm thinking about what to do with stripped carbon on the front fork - to me it seems that only paint is damaged and I'm thin...
Read moreCampagnolo Atlanta Quandary
Lastest post 4 days agoHi! After a holiday in Italy last year where I rented a vintage colnago with Campagnolo Atlantas, I was convinced that over the next year I was going to build up a Campag vintage bike of my own. Fast forward a year, I managed to build up a Giant Cadex with full campag 10sp with a set of Zondas. Last week I managed to pick up some Campagnolo Atlantas with Record Hubs and was thrilled. Then, I ...
Read moreTools required for SunTour Cassette removal
Lastest post 4 days agoHi all, I'm aiming to remove this SunTour Cassette. Beyond a chain whip and wrench, it appears I need a special lockring. From my guesstimate, it seems like 'Cyclo 2 Peg Freewheel Remover' will do the job or some other of 2-notch lockring. I don't know how common these are at Bike shops and was hoping if anyone can offer some suggestions....
Read moreChip in carbon frame. Do I need to get professional repair?
Lastest post 5 days agoI had a minor collision with another cyclist. The bottom of the fork of the other cyclist’s aluminum frame hit the rear left side of my carbon frame and chipped it. I tapped around the frame with a penny and the sound is the same. Do I need to get this repaired? 5C9FA87C-F47E-404E-8CAB-A0213D6FBD24.jpeg (Size: 46.75 KB / Downloads: 25) ...
Read moreMODERN GRIP AND THUMB SHIFTERS: POOR ENGINEERING?
Lastest post 6 days agoSo as some who rides and maintains bikes from the 1960s to through the 2000s, I find disturbing that there are some many problems with modern shifting mechanisms on low to midrange bikes. I have an engineering background and it seems that basis quality in function and durability has gone by the wayside in this department. Is just a cost issue? I would be embarrassed as a manufacturer if I had the ...
Read moreShimano GRX shifter with 11-speed mountain derailleur
Lastest post 7 days agoHey all, My CX/Gravel bike came with a Shimano GRX-810 (1x) drivetrain. The derailleur has a 34T max cog and, living in a flatter area, it's more than fine but I'm planning on getting in some climbing-heavy gravel rides later this year so was looking to get something that can take more teeth in the rear. A little digging around has identified the XTR-M9000GS, another 11-speed RD, as a viable opti...
Read moreNeed advice on crack in steerer tube
Lastest post 1 week agoLooking for ideas and opinions on this crack in my steerer tube. It seems pretty small and only on the outside surface, and the carbon is rather thick too. I have enough room to potentially slam the stem by cutting the area off, or I could try using a metal tube insert to brace the area. Or is it small enough to ignore for now? What do you think 20210723_211713.jpg (Size: 19.97 KB / ...
Read more
