So I've been on a journey to fix a worrying squeaking noise that is impossible to replicate on a stand. When I am cycling, the rhythmic squeaking noise seems to come from the front on the bike, but I am only like 75% sure of that.
I first took it to the local bike shop where the mechanic diagnosed worn out bearings in the front hub, but as he could only fix it in a few weeks, I serviced it myself (the cones were indeed pitted, and I have replaced them, axle and bearings with the correctly sized identical ones). When listening to the hub through a screwdriver, it is revolving very smoothly now.
It didn't resolve the problem with squeaking, even though later the mechanic confirmed that the hub is now perfect (took it to the shop again as I ran out of ideas), but he didn't suggest anything else.
Here is what I can tell for sure about the noise:
- As mentioned, it is impossible to replicate it on the stand.
- Front hub as the source of it can now be ruled out.
- I still think it's the front of the bicycle that is squeaking.
- The noise is rhythmic and sees to happen once per wheel revolution - or very least its frequency depends on the wheel rotation speed.
- It doesn't seem to depend on pedalling - whether I pedal slowly or fast, frequency of squeaks seems to only depend on the actual wheel rotation.
- When I stop pedalling completely, the noise doesn't disappear or become less prominent - so I haven't checked the bottom bracket and drivetrain yet apart making sure there is nothing obviously wrong with them.
- It is not brake pads or anything else rubbing against a rim - the wheel is reasonably true, and disabling the V-brake completely by undoing the cable doesn't affect the noise.
- If it makes a difference, it's a folding bike with 20" wheels (Dahon Vitesse).
- As it is a folding bike, I check the frame lock and lubricated it, and it didn't help as well.
- Steering doesn't seem to affect the noise volume.
- It is not the seatpost or saddle (checked that carefully because the noise is only present when I am riding the bike).
What should I check first now? Abandon the idea that it's the front of the bike that is squeaking and check the rear wheel and/or bottom bracket bearings? Check the handlepost (it is new as it has been replaced this winter)? Nuke it from the orbit?