hey there, my name is tristan. ive posted here before but i spend most of my time in the fixed gear side of town.
this all started a while back with my old bottom bracket, every once in a while when im spinning hard or just basically hauling a$$ i would get an inconsistent clicking sound, very mild.
i then go to buy a new bottom bracket and i install it today, thinking that the problem is solved but now its even worse. every rotation in the same spot when im applying pressure to the left crank i hear sort of a clicking sound. AND I CAN FEEL IT through the bottom bracket into my right crank. jesus, its like a nightmare.
if any of you boys can chime in, thatd be very nice and would make me happy.
and before anyone mentions loose crank arm bolts, i tightened those little suckers as tight as i could.
could it be chainring bolts? maybe my left crank arm is cracked?
THANKS

Pedals? Are you running your chain tension too high? A lot of chainrings aren't exactly round, and even more so, don't mount on the crank exactly concentric, so your chain tension can vary slightly as the crank turns. (I don't have any fixed gear, but I run IGH, so I'm familiar with this minor condition) Too high of a chain tension can be hard on your bearings, [rear] wheel and bottom bracket. Do you have chain tugs installed?

Edit: bad phrasing. Too high of a chain tension can be hard on your rear wheel bearings and bottom bracket bearings.

I take it you mean you're feeling it in your foot, perhaps? Sort of like a vibration? Might I suggest checking everything having to do with your Pedals.
Check to make sure they're tight on the crank arm, check to see if they have moderate axle play. If they're Platform or separate cage/ body pedals,
check the cage screws. Of course, check AND lubricate the chain ring bolts as necessary.

Long shot here, but attempting to catch all of the variables instead of the obvious ones.

Don't know what kind of BB you had or now have, but as the problem continued and got worse let's assume that the cause is something that did not change. As others have pointed out the pedals are a prime suspect - either attachment to the crank arm or flexing of the pedal structure. But don't just tighten.

Substitution is always a good isolation technique - try a different set of pedals, but make sure to grease the pedals and to clean the flat area on both pedals and cranks where they meet. If the noise is gone then it's either the pedals or the pedal/crank interface. If not it's likely the crank arms

If it's the pedals (or if you don't have a pair to swap): Clean both the pedal threads and the flat area on both pedals and cranks where they meet and reinstall. If they still make noise it's something moving on the pedal cage.

If it's the cranks: Remove the cranks and clean both the spindle flats and the inside of the crank arm with fine steel wool and then wipe with a rag. No need to lube beyond residual oil on your fingers.

my chain tension is a peg tighter than it should be i guess, my frame has chain tensioners built in.
and my crankset is decently round, in other words its not some cheapo crankset.
thank you bro for your input.


its not really a vibration, when i think vibration i think of many small clickclickclick in quick succession.
the noise im talking about is like a single DING(sorry i should have used the word ding originally) whenever the left crank arm reaches 11 o clock position and i can feel a slight movement in my right crank arm from it. i will definatly check the chainring bolts.
thanks man

If it's in the same spot each time, what about a stiff chain link?

PP mentioned a stiff link... maybe a link pin (the one you last re-installed, perhaps) is sticking out of the plate a tad too far?
Or, what about a chain link catching a burr on one of the chain ring teeth? You get the ding in any gear, regardless of ratio?

"... the noise I'm talking about is like a single DING whenever the left crank arm reaches 11 o clock position and i can feel a
slight movement in my right crank arm..."

Slippage? Free play? Can you wiggle the crank arm on the spindle?

Hmmm...

I had some similar creaking recently and tried three separate BBs before I figured out it was my seat/seatpost. If you are feeling something, then that may be different, but It never hurts to check other things.

good question, i forgot to mention this.
not every time, but sometimes after riding i would inspect my crank arm and push it to one side and the left crank arm would shift very very slightly and then never do it again until after i ride for some time. the sound from the arm moving is basically the same sound as i explained before.
i dont think its a chainlink because ive never broken the chain and put it back together, the chain is actually quite new and ive only seperated it once to put on my bike.
im going to my co op in the next couple of days but until then, im gonna have to suffer and avoid riding my bike just incase(this upsets me since it will be pretty nice outside)
if it means anything i have IRD defiant cranks and shimano un55 bottom bracket 68x107.



a guy i talk to told me he heard a dinging sound from his cranks aswell and it turned out it was a piece of hot glue on his shorts hitting the seattube

Chase the BB shell threads or put a wrap or two of teflon tape on the new BB?

Well if you can shift the spindle by pushing on a crank arm, that sounds like your problem. Your un55 BB is one of a couple of the Shimano BB that has a lip on the end of the left side BB ring that tightens all the way to the edge of the BB shell. What it sounds like to me is for some reason the BB is not being held tight enough by the ring. You said you bought a new BB; was that new to you, or a brand new BB? Either way, did you use the new left side cup? This cup has a rubber seal inside that holds the BB in place. If this is missing or has been damaged you will experience what you are describing. This happened to me once when a bought an used BB without the left ring. I tried using another ring and although it felt tight, it shifted as you are describing and caused a creaking sound under hard pedaling.

i am still unsure if the movement is comming from the axel or crank arm. from what i can see (and if i understand what you mean by lip). then the right side of the bb is protruding about 2mm. the new bb i got is brand spankin new. but im looking at my old bb right now. the left cup doesnt seem to have a rubber seal in it?
wow i just had a thought. is there any specific order in which you instal the bb?(i installed the body first (drive side), then the seperate cup 2nd) or maybe i installed it backwards? noway for me to tell until i go back to the co op.

great advice man, really got me thinking.

make a quick check to determine if your crank arm is hitting the chainstay, or maybe the chainring is hitting it. it's a longshot, but easy and quick to check.

The correct order is drive side (right) first (with a few exceptions that don'y apply to you) all the way to the lip, then non drive as far as it will go; with a UN55 the left side cup should also tighten all the way to the lip. Just for kicks can you take a photo?

The bolt may be totally tight, but if the square taper in the crank has been compromised, it can still shift slightly.
Do you have a spare are you can try as a test?

I may be able to borrow one from thr co op. Would riding it without properly torquing the crank bolts lead tothis problem?

yep!

Just to let you fellas know my right crank arm was nipping the chainstay with each rotation.
It turned out my bb was a little too small but before my crank bolts werent tight enough(so the crank barely touched until i tightened them)
I bought the appropriate bb(110) and the crank arm hit the chainstay more than ever. I solved this problem with a spacer, i just have two questions for you guys.
How come when comparing a 107bb to a 110bb only the NDS spindle is longer(110bb)
And how common is it to have to use a spacer in your bb on your track frame? Nobody ive ever talked to had to use a spacer

If you're comparing apples with apples, it beats me. But there are a zillion different-sized BBs, according to which cranks they belong with...

sorry i should have clarified. a shimano un 55 i think...the mechanic at my co op said he thinks the longer length on the nds is because its sopose to be used with a spacer?

Shimano cartridge bottom brackets below 110mm are asymmetrical.