Hitch and Noise While Pedaling

[Dulce]

Hey Guys,
New to this and just trying to get going with doing some bike repair on my own so I'm sorry if I sound like an amateur. So my problem with my fixed gear is that every time a pedal with my left pedal I get a cranking noise coming from it. Also almost every time I pedal I get what I can only describe as a hitch in my rotation (not a smooth go around). I took it to a bike shop and they said my Crank was loose and they tightened it but that only helped me out for one ride. Then after that I went to another place who told me my crank was stripped so I bought a new one and installed it and that worked for about 2 days (3 rides). so I'm out of ideas about this whole situation. I was thinking it might be the bottom bracket but that's an expensive guess that I don't just want to make blindly. Any help you guys could give me would be awesome.


-Kev

[GeorgeET]

Bottom brackets are not that expensive you can get a Shimano UN54 or like for under $30, less than a crank if the terms used is correct. IT could be that the shaft got rounded and crank moves . Also check and make sure the rear gear is tight. No idea how old the bike is. Check pedals too and see above post.

[DaveM]

The creak is a classic sign of loose/damaged crank arm or a loose pedal.
The "hitch" might be unrelated. Does it happen right when you start putting down force on the left crank? Or does it interrupt the smooth rotation of the cranks at other times. If the later, it could be a lot of things: binding/overtight chain, bad bearings in wheels or BB, loose chainring, etc.

[Dulce]

First off thanks guys for the responses.

It happens at around the 10-11 o'clock point. Another detail is that these issues only happen when I'm actually riding. I tried to recreate the problems with my bike on a stand but with no luck it moves fine without pressure on the pedal. I also took everything apart and inspected the BB but I am really not sure how to detect if there is a problem with it. It spun fine but I'm not sure what a damaged BB looks like compaired to a functional one.

[DaveM]

It sounds like the new crank arms is loose/damaged unfortunately. If the shop that sold it to you installed it right it should not have given you trouble this quick. It could be that the axle on the BB is damaged, this would be fairly unusual and somewhat hard to see for the untrained eye, but it's possible. Could also be that the threads on the BB spindle are stripped and so the crank arm didn't get tightened correctly, this should be more obvious visually.

I would start by going back to the shop that sold you the new arm and telling them it's creaking again and you're worried it loosened up again. They either installed it wrong, there's something else going on, or it's a completely different issue that we haven't identified.

good luck