Originally Posted by
Brocephus
I'd say that's a hella lot more than your typical, tiny, mystery-creak ! Dieselgoat makes a good point about the BB being on everyone's short list, then not being the actual problem, but that does sound like it's in the BB, or the crank.
But, it also had kind of a hollow, woody sound that made me suspect a crack in the carbon frame somewhere. You check that closely already?
How does it sound when you spin the cranks, with no one on the bike? How old is the bike ? (I'm wondering how old it was when the original owner replaced the BB.)
I have looked over the entirety of the frame. If the frame itself is cracked then it's somewhere not visible to me (i.e.-somewhere recessed or behind components). Additionally, the thing rode fine with no noise for quite a while. And there was no drop/laying down event that precipitated the noise. It's just become gradually louder and more frequent.
Spinning cranks with the bike unloaded, it will still mostly make the noise, but it's not as harsh. And sometimes (but with no consistency) I can hop on the bike and it will be quiet for the first mile or so. And then most other times I'll get on and it's immediately present. But I'm almost to the point now where it's like 9/10 noisy.
Age? Great question. I don't think I ever got a year from the guy. But the 5.9's appear to have the capability to be at least 9 years old now. Unsatisfactory answer, I apologize.
And when did he replace the BB. You know, that's a good question. He had only said that he had done it recently. But I know I think things are "recent," but when I really think about it it'll be something where I only had one kid at the time which means it was least five years ago. Getting old sucks.
Originally Posted by
Unca_Sam
I'm pretty sure it's on Sheldon Brown's website as a tip for diagnosing creaks and BB problems. Put your bike in a stand so you can turn the cranks; put your ear on the 'horn' of your saddle; turn the cranks and listen. The bike frame will amplify sounds in the BB shell and transmit them directly to your ear. If the sound is a crunchy rumble, it's likely your bearings, if it's smoother steel on steel sound, your BB is probably fine, and it's time to look elsewhere.
I can't do this, but you can. Isolate the components of the drivetrain (and maybe marvel at the ingenuity) and test them one by one. Narrow it all down and you'll get your noise, then you can find a solution.
Happy hunting!
Thank you for these tips. It looks like I have my weekend activities all lined up now!