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 Just wanted to know how often a bottom bracket needs to be replaced. Would it be like once a year or does it really depend on how often and how much you ride your bike? And finally how would you know if it needs replacing? Would you feel an obvious problem whilst riding the bike? Thanks... Read more >>
Hi, I'm building my first bike from scratch, a road bike for my wife. I have a Ridley Asteria frame (68mm BB shell) and an FSA K-Force Light crankset. I cleaned out the BB housing, greased it up and threaded the BB cups without issue. My problem is with the crank axle. If I just have the drive side BB cup in, the axle pushes all the way through like it should. If I put the non drive side cup in, the axle stops about 5-8mm short of pushing through. If I take it out and try to put it through from the wrong side it fits through the non drive side cup no problems but still stops short of pushing t... Read more >>
Hi, My wife had completely worn out her 2011 Rockhopper SL Comp drivetrain. I've ordered a new cassette and chain but have decided to replace the entire crankset rather than order 3 new chainrings. The current BB is a Shimano BB-ES25 octalink 68x118. I've messed with everything many times but ever a BB so I'm trying to learn about compatibility. Here is the bike: http://www.specialized.com/au/en-au/bikes/archive/2011/rockhopper/rhintrockhoppercomp#specs From what I gather, I can fit any GXP or Shimano 3x9 crankset as a replacement into this frame? Eg. http://www.chainreactioncycles.com/Mobi... Read more >>
Hello, I have a 2009 Trek 7.3fx. I recently bought a new BB, chainset and front mech for it. All of the parts (Shimano Alivio and UN-26 BB) are supposed to be compatible, but now that I have installed them all, the front mech doesn't work. No matter how hard I pull it without the cable on, it only ever comes level with the biggest chain ring, and won't encompass it - so I can't change into top. Is it possible that even though I got exactly the same size BB (68x122), that the new FM needs a shorter BB? Many thanks!!... Read more >>
Hello All My bottom bracket is falling apart and I'd like to replace it with a brand new one. From reading sheldon brown's wesite, i understand that some older raleighs have peculiar BB specs. How do i find out if this is the case with ym 1968 record, and what are the implications for finding a new BB? thanks!... Read more >>
I'm replacing the Bottom Bracket on a 1991 Bridgestone MB-3 and it looks like the bottom bracket pre-dates most of the tools I have. Here are a a couple of pictures that I took. On the drive train side, it's hard to see in the picture, but there are 2 flat surfaces on the BB that look like a large crescent wrench would fit. I quickly measured it to be about 38mms. [attachment=3960] I took the non-dt side lockring off and then came across these holes that I guess you could fit a spanner into? Seems like it's going to need a lot of force to get this off, but maybe a spanner would work... Read more >>
Alright, so I have a FSA K-force crank with a MegaEXO BB 68mm width, and it clicks certain times while riding, and I feel the click up through my feet and so forth. Sometimes the click is so loud other riders can here it and ask what it is. I have done a lot of trouble shooting to see if it might be something else, pedals, drivetrain, etc. It is not those, it is the bottom bracket crank combo. If I clean and lube the crank and BB interface areas, as specified, the click goes away for a short while; 20-30 miles, then starts up again. I have even ran the bike with a Dura Ace 7900 BB that I have ... Read more >>
I know this question has been asked a million times, so I will add another to the count The bottom bracket as seen in the attached pic is of a CCM (Canadian brand) entry level bike from the 80's. The diameter of the shell is 2 inches, roughly 50 mm. There are no threads. From what I've read, it appears that I need an adapter kit to fit another type of bottom bracket? What are my options? Are there any advantages? Thanks in advance.... Read more >>
I have chosen a frame for my single speed build but will this bottom bracket fit it? Frame- http://www.nashbar.com/webapp/wcs/stores/servlet/mProduct4_10052_10053_516649_-1_catNav Bottom bracket- http://www.nashbar.com/webapp/wcs/stores/servlet/mProduct4_10052_10053_536893_-1_catNav Also will whis crankset for that bottom bracket? Crankset- http://www.nashbar.com/webapp/wcs/stores/servlet/mProduct4_10052_10053_501424_-1_catNav... Read more >>
Hi, I just bought a new Vintage 1980s bike frame. How do I know which Bottom Bracket to use for the new frame? Sorry, I'm new so I may ask some stupid questions.... Read more >>
I think the time is coming where I am going to have to change the bottom bracket. I have a Roadmaster Mt. Fury 26" men's mountain bike r4416wmgt. Can someone suggest the proper replacement bracket and tools needed for the change? Thanks, Josephine... Read more >>
Hi all. I'm new to repairing bicycles and hoped some one might be able to assist me with an issue I'm having. I recently bought a 1984 Centurion LeMans RS that needed some minor repairs. Lately it has started making a clanking noise, something like the sound of striking metal when it's under tension, at certain times while pedaling. The noise only occurs when I am actively pushing on the pedals. When I start pedaling from a full stop, the sound is louder. Sometimes the sound occurs when I am not pedaling hard, but it is not nearly as loud and happens rhythmically which each full turn of the ... Read more >>
I'd like some advice on what tools I'll need for this bottom bracket (see attached photos). Ultimately I'd like to re-grease or replace it. Thanks so much for you're help!... Read more >>
ok. basically I jacked up one of my crank arms.(non drive) it was truvativ touro set that I have been riding with for about 5 years or so. Id like to keep my bike looking how Im used to it. I know im weird. its a motobecane phantom cx. nothing much but I love it. anyway. I cant find a square taper crankset or even the correct size bottom bracket 110.5 (mines a rpm 7420) but what I can find is a power spline set. and a powerspline 113or118. I dont even know if the taper or spline makes a difference or how much of a difference the bottom bracket size from 110.5 to 113. would the power spline ... Read more >>
I need to replace my 110.5 mm bottom bracket. There is more choice and a lower price for 110mm bottom brackets. Can I use the 0.5mm shorter one. Is the difference a simple 0.5mm or is there a reason for the very slight different size?. Thanks... Read more >>