Thursday, July 12, 2007

Bottom Bracket Racket

My bike just got the equivalent of a hip replacement. It's like a spry young 75 year old now. (How many bike years are in a human year?) The old bottom bracket, that clunked on every stroke of the pedal, has been replaced with a new solid sealed cartridge bottom bracket.

Last year, and the year before, I got the bottom bracket regreased with new ball bearings. I asked for a sealed cartridge, but the shop always told me that it was difficult to order the right one due to the strange size. They went ahead and repacked the bottom bracket without calling to ask if I wanted to wait for the right part to be ordered.

This time, I didn't want to make the same mistake, so I brought it to a different shop, one in Toronto that has told me before that they take pride in fixing any type of bike. The word from their mechanic was essentially "of course we'll put in a sealed cartridge BB. We would have done that if you didn't ask." And a day later, it was done.

Pinarello's drawing of a bottom bracket. I recently learned that the chinese word for bottom bracket means middle axle, which seems much easier to understand than our word.


A lot of people would have classified my bike as unrideable with the old bottom bracket. On a functional level, though, the pedals still rotated in a somewhat circular fashion, and the large cog was able to pull the chain, the chain turned the rear gears, and the bike went forward. Somehow it didn't cause gear shifting problems. Anyways, because the clunking would start 1 month after the BB overhaul, I didn't want to bring it in and have to repeat every month, so I lived with it. And now that I look back at it, I must have ridden about 2500 kilometres with it like that. Probably not the smartest thing, but it says something about how simple and effective of a machine a bicycle can be.

Now that I've proven a bike can be ridden with a clunky bottom bracket, I'm happy to close this case and move on. It feels like I have a new bike. Only smooth, quiet pedaling is in my future. (Except for my fender that keeps rubbing).

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Darren J 7/12/2007 01:00:00 PM

1 Comments:

repetitive bottom bracket problems induced me to give up on the hacks who claim to be bike mechanics. wd40 and liquid wrench are evil no matter what the kooks say. solvent residues prematurely break down the lubricants.
sheldon brown has a great (archived) article on rebuilding bottom brackets with loose balls. i wished i'd read it before giving up and getting a cartridge for the bike that prompted me to do my own in the first place.

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