I've had a very faint repetitive noise from my bike for a little while but never really loud enough to hear it, if that makes sense. Yesterday I was riding and it seemed more noticeable, like a squeak (only not so high in pitch) so I'm calling it a chirp. It seems to be occurring at the same period as a wheel rotation so my initial thoughts are that it's related to a wheel bearing. I can NOT replicate the chirping sound (it's pretty faint while riding too) on the repair stand. It occurs whether I'm pedaling or not and whether I'm seated or not. I could be mistaken but it only seems to be noticeable when I get going, so 15 mph +.
The bike's a 2007 carbon Spec. Roubaix and I have 3 year old Easton EA90SL wheels on there with a couple thousand miles on them. Maybe 4.
I've been perusing youtube looking for maintenance videos but aside from checking hub preload (mine seems to be fine) and switching out freehub bodies, I'm not really finding anything relevant. I believe the hub bearings are sealed cartridge bearings, so I'm not sure there's any maintenance I could do on them anyway.
Any ideas on what I can check? I realize troubleshooting somebody else's noises over the internet is nearly impossible, just looking for ideas on what I can check.