Bicycle Mechanics - Creaking noise from cranks when applying force to pedals?
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03-15-06, 09:52 AM
Hi all, I've had an audax racer for only 4 months now (bought new and ridden through the winter) and now I'm getting an annoying creaking/grating sound coming from the crank area whenever I pedal hard. Any idea what this could be?
I've already tried replacing the pedals and the noise is still there. Tends to happen more when the left pedal is being forced down.
If it's the BB then my next question is how could the BB be shot so quickly? I only ride about 10 miles per day on this bike.
03-15-06, 10:10 AM
BB is a possibility, as is the connection between the crank and BB - it's possible that connection isn't tightened enough on the left side. You should first check for any play in the crankarms, which could be from (1) loose connection between crank and BB (2) loose BB connection to frame (3) shot BB bearings. Make sure to check both crankarms for play, as the left might be more loose than the rt. Next, remove the cranks from the BB, and spin the BB spindle between your fingers, to see how the bearings feel. If they're quite gritty, then it's possible that the BB bearings are causing the noise. If so, you can live with it until the BB gets bad enough to where it gives resistance to the pdeals, or you could replace it.
03-15-06, 12:33 PM
Along with what Tim suggested, the noise may be coming from the bottom bracket cups. These are a frequent source of noise if they weren't lubricated adequately or tightened sufficiently when installed. Removing the cups, adding lots of grease or a few turns of teflon tape and reinstalling with sufficient (read LOTS of) torque may solve the problem.
03-15-06, 01:12 PM
Time for me to say what I always say:
If the frame wasn't faced, the BB cups could effectively be crooked, which means the BB has essentially been running on only 2 bearings, which means it could easily have gone out this fast.
03-15-06, 01:23 PM
Yeah, I should have elaborated on the factor that I'd listed above:
> (2) loose BB connection to frame
By which I meant what HillRider and Landgolier are referring to.
03-15-06, 01:30 PM
I have the exact same problem, and it's happening after a whopping 4 rides (~72 miles). I'm guessing it wasn't tightened properly, as I had the same problem with my cranks. Shows what I get for NOT getting a torque wrench when building a bike.
Landgolier, if the BB cups ARE crooked, is there a way to tell with a level or something when the BB is installed?
As a first easy test I would pull off the crank arms,
wipe down the spindle and inside the arms,
& put cranks back on.
This worked for me last summer when my cranks/bb were creaking after a rainy spring of commuting. Same thing, they only creaked when I applied force and not when I would just spin the cranks.
It is a whole lot faster & easier than opening the bb and repacking.
IANAM, but...I've also had this symptom created by loose chainring bolts, a chainring installed the wrong way (such that the chainring bolts couldn't be properly torqued), and a bottom bracket shell that was about to separate from the frame (someone else's bike). Probably not the latter since its a new bike, unless it was very poorly made. But yeah, typically it's the crank-spindle connection or the BB cups. Creaking, in my experience, is usually from an under-tightened or ungreased fastener (some will argue that the crank-spindle connection should not be greased...), but grating is almost certainly an indication of a worn or improperly-adjusted bearing surface. If you can get the creak by just pulling the crank away from the bike, then its probably just a matter of taking off the crank, cleaning it and the spindle, greasing the surface, and getting it back on there tight.
03-15-06, 01:56 PM
I suppose you could rig something or use calipers or whatever to see if a BB has been faced properly, but the easiest way to tell is to just pull the BB and see if there is still paint on the outside surface that the cups run up against. If there is, it wasn't faced; most new bikes aren't, especially in the under $2k class. If it is bare metal, it probably was, but you'd need a facing tool to check it.
This isn't the most likely problem (chainring/crank bolts are), but it's worth checking for, and if you like your bike it's worth having done.
03-15-06, 10:35 PM
Before you go ripping the bottom bracket apart, make sure the noise is really coming from there. Often the seat or seatpost will creak with each revolution as your weight shifts, and it sounds like it's coming from the cranks. A quick check is to see if the noise goes away when you stand up to pedal.
I had a reallllllllly loud creak, also when forcing down on the left pedal. After trying everything suggested on the forum, I finally bought a BB tool and removed it. It turned out to be a crappy BB: The bearing cartridge was not fitting tightly on the spindle, so the inner race would rub against the spindle shoulder. I then tried everything to solve this including the very strongest Loctite, but after some months it would just start up again. I gave up. Sold the bike with creak. Only a new BB would have solved it, but the LBS would not come to the guarantee party.
06-01-06, 08:02 AM
I had similar noises which I blamed on the bottom bracket and mine simply turned out to be a stretched chain.
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