Wednesday, March 4, 2009

Bottom Bracket Bearing Aggravation

I got my bottom bracket tool tonight and happily removed the bottom bracket. No problem. But when I realized it may not be very easy to repack the bearings, my heart sank. I searched the web for the bottom bracket - RPM BB 7420, and found many places that would happily sell me a new one for $22 to $25 bucks, but found no help at trying to clean and repack. Actually, shows me how to repack the sealed bearings, but these bearings look like they are pressed onto the spindle. Lacking the knowledge to remove the bearings from the spindle and the BB housing (and lacking a press to put them back on) it looks like I am stuck with buying a new bottom bracket. Bummer - I was hoping to repack them and go. Does anyone know how I can repack these? I don't want to put this in the landfill, but I don't know if I can recycle it. How easy it would be to repack loose bearings.


Rat Trap Press said...

Did you ever get any help with the bottom bracket question? I always thought the sealed units were meant to be replaced rather than repaired.

Big Oak said...

Never received any comments. I didn't realize that they were to be replaced until I tried to take the bearings off of the spindle (gave up on that idea). I cleaned the outside of the bearings and spindle and stuck it back in the bike. It squeaked a little for the first few miles, but seems to be working OK now. I am looking around for a bearing unit that is easy to service, like a Phil Wood BB, but the cost for those is too high for me. I've got some long rides coming up this spring, so I will need to replace them soon. I have about 2,800 miles on this set of bearings, so maybe it's time.

Doohickie said...

Seeing your post gave me the courage to repack the bottom bracket on my old Raleigh Marathon. It's a ball and cup design (not a cartridge). I put it all together last night but didn't get a chance to ride it until this evening and well... I needed to tighten things up a big since the change ring wobbled back and forth almost a quarter inch with every cycle!

I tightened it up and it's much better now... no more clicking under load.

Jon said...

Most cartridge bottom brackets are not rebuildable. The upside to that is that even cheap Shimano sealed bottom brackets will normally return many thousands of miles of service (unless submerged in water, regularly).

Most noises associated with these bbs are actually produced at the bb/frame interface. Removing the bb, cleaning the threads and then applying anti-sieze compound (in an aluminum frame) or plain old grease (in a steel frame) to the threads will usually cure this.

Cup and cone bbs will also last for many, many miles. The cost is frequent maintenence and consumption of quite a bit of grease.