I have a clunky bottom bracket and have a few concerns.
First, the bike is 22 years old, with Dura-Ace 7400 components. I estimate the total mileage on it to be about 20-25K.
The BB was serviced/repacked one year ago.
About 3 weeks ago I noticed a clunk from the bb area, which gradually became stronger and louder. More noticeable under load....I took it to my LBS (not my first choice but close to work) and they said the BB was loose and needed an adjustment...they did the work, and the bike was fine....for about 12 rides (approx 300 miles)....now the clunk is back.
I brought it back to the LBS and the wrench there spent 10 seconds pushing on the pedal in the 6:00 position and said the BB is not loose, and if the clunk is back then I need a new bottom bracket.
My two questions/issues:
1. Based on the above story do I really need a new BB or should I get a second opinion from another mechanic? I suspect I may need a new BB but the re-evaluation seemed perfunctory.
2. Given my "vintage" components, should I seek out a NOS shimano D-A or 600 BB from the 80's? Or just get an off-the-shelf square taper BB from the LBS of whatever brand they have?? I suspect it doesn't matter, but I don't know much about bottom brackets. Obviously I can't get a modern D-A or ultegra one since they have gone to octalink, and I need a square taper to fit my crankset.
3. Given the scenario above, am I risking anything by doing some more rides on the bike? I dont suppose there will be any catastrophic failure but I dont want the bike to fall apart in the middle of a ride.
Any comments/suggestions appreciated!!