Bottom Bracket Bicycle Repair

About 3 years ago I decided that running was not a good form of excersize for me due to chronic leg issues, so I decided to switch to biking.  I proceeded to buy the coolest looking $70 bike I could find at Fleet Farm.  It was a mountain bike.  It was never very comfortable, the shifting never worked all that well, and basically I got what I paid for!  However the bike has served its purpose very well over the past few years; it gives me a very good cardio vascular work out and because the gearing is so inefficient for road biking it gives me a very good leg workout when I ride it in the higher gears without too much speed.  This summer the pedaling mechanism started feeling looser and looser.  By the time I stopped riding it a few weeks ago the whole mechanism was clunking back and forth and was not tight at all.  I am not a mechanical engineer, and frankly not all that mechanically inclined either, but I like to figure things out.  So I started trying to take the pedaling mechanism apart to figure out why it was loose.  I didn't get far.  Basically there is a decorative cover (easy to take off) over top of a 15 mm nut (easy to take off) that appears to be holding the left pedal on (non gear side).  After that I got stuck.  I consulted the manual.  Sure enough, the manual said if the mechanism gets loose you need to tighten the bearing cone on the crank arm.  In order to do that on my bike the left pedal must be removed with a special tool called a crank arm extractor.  I went to several bike shops before I finally found the one I needed.  It seems that most bike shops do not cater to do it yourselfers for much more than the simple repairs and tune ups, but there's no way I was paying to have this fixed, because it would cost more than the bike cost!  Plus, I wouldn't want to miss out on all this fun.  After I got the crank arm extractor tool I was able to get the pedal off easily.  Then I had access to the cone.  It appears to me that a bike shop would probably have a special tool for tightening this but nothing was mentioned in the user manual.  A really long open wrench would work.  A regular wrench really can't grip enough of the cone to get enough leverage.  I ended up using a slip joint pliers - crude but effective enough.  I was able to tighten the cone down, but it seemed to take way too much force.  Since I was this far, I decided to take the cone off and have a look at the bearings.  The bearings were ball bearings in a little circular retainer.  Most of them fell right out of the retainer when I took it out (I didn't lose any though!).  Upon inspection, many of the bearings looked quite worn - they had flat rough edges.  I'm not a bearing expert, but they didn't look good.  So I decided to try to replace them.  With a calipers I determined that they were 1/4" bearings and I measured the retainer size at about 1 1/8" diameter, and there were 9 bearings.  I searched everywhere on the internet for this retainer.  I never actually found anything that definitively appeared to be the same part.  The main problem was that most sites did not give enough specs to determine if it was an exact match.  Eventually I settled on a Pyramid #27 bottom bracket bearing, 9 x 1/4, 3 piece which I found on Amazon.com from an external vendor Niagara Cycle Works.  It only costed $0.83.  Just in case it wasn't right I ordered a bag of 1/4" ball bearings as well and figured I'd make the existing retainer work with new bearings.  I bought some white lithium grease from the hardware store to lubricate the setup.

The bearing retainer arrived today.  It was an exact match.  I quickly reassembled the bike, and it is as good as new.  It didn't take much tightening of the bearing cone at all to get the whole mechanism very tight.  I can't wait to ride it tomorrow morning!

It did occur to me during this whole process to just buy a better bike (actually strongly suggested by my wife).  Buying things is never straightforward for an engineer though.  There would be spreadsheets, detailed analysis, trade offs, visits to every bike shop in a 50 mile radius, internet searching, reading bike forums, etc.  In short a whole lot of wasted time.  I really would like a good quality bike, but bike shops intimidate me.  Any place where they charge high prices is intimidating for a novice because you don't want to get screwed.  Some sales people will "see you coming" and try to take advantage of you.  I really just want to go in, try a couple of bikes, pick one, pay a fair price and leave knowing that I didn't get taken.  Basically the Fleet Farm experience, but with a higher quality bike.