Diagnosing a loud creak
 

Hi all, I began cycling a few months ago to get back and forth from work. As I wasn't sure if I would stick with it or not, I started off by getting a cheap barely-used MTB from a relative - a Decathlon Rockrider 5.1. I've been enjoying it, but it started developing a very loud creak just over a month ago, after only around 400~ miles. There's a video here, where I'm putting pressure on the left crank, and it sounds even more painful when I'm pedalling properly. :)

The bike creaks loudest when I'm applying torque to the pedals, though it never completely disappears even if I drop to lower gear. If a hit slight bumps while coasting, there is also a quick creaking sound. The above video shows how I can replicate a creak while off the bike, but I cannot get any sort of noise if I turn the bike upside down - I've tried pushing and pulling the cranks in all directions while on the highest gears, but I still can't create any horrible noises. Lastly, when I first set off in the morning, the bike is briefly quiet. I can get down the road without any problems, then within another 100m it's at full volume again. Given me a few false dawns while trying to fix it! :notamused:

I'm aware that this is typically due to the cranks or the BB. I've removed, cleaned, greased and reassembled a couple of times (both with and without greased spindles), and there hasn't been any noticeable impact. I am a newbie 'mechanic', so I admit that they may be under or overtorqued, but I would've expected at least a brief change in sound? The crank bolts feel like they are slightly looser when I come back after my commute, so I might remove the cranks tomorrow and upload a photo to see if anyone can spot if they're rounded or not.

Outside of that stuff, I've also tried greasing my QRs, the dropouts, the derailleur hanger, the seatpost (though the creak is just as loud while standing) and probably a couple of other things which I've forgotten about.

So, does anyone have any suggestions of what else to check, or ways to diagnose/eliminate potential problems? Thanks.

(EDIT - For the information of anyone who finds this thread after doing a search, it turns out my problem was a slightly loose rear hub. Turns out I could actually replicate the noise by giving a quick forceful push onto the side of the rim! I'm guessing pedalling caused the dropouts to flex slightly, resulting in more hub play and therefore more noise?)

Where about does the noise come from, Front wheel, Rear wheel, Bottom Bracket ? to me it sounds like metal being forced to rub against other metal. Does the noise happen when the cranks are spun backwards ?

Sounds like something is not engaging properly and slipping. Are the cranks on correctly.

Regular "ticking" might be a loose spoke!

- Wil

Bicycle frames transmit vibrations (creaks) very well, so where you think it's coming from might not even be close to the real source.

If you stand up and pedal, does the creak stop? make sure your thighs aren't rubbing on the saddle or this test won't help diagnose the problem. If it only creaks when you're seated, you might try some grease or assembly compound on the seat rails. If that doesn't help, use assembly compound on the seat post (no grease).

If it creaks seated or standing, does it creak while pedaling or while rolling? I'll guess it doesn't creak while sitting still. If it creaks while not pedaling, try tightening the skewer. If that doesn't do it, try a drop of oil on the NDS rear spokes where they cross. if it creaks only while pedaling, is it a cyclical noise - like every rotation of the crank? If so, try pedaling with one leg at a time and see if you can isolate to one side or the other. Loose cranks could be it, but it could be a pedal as well.

Ride with no hands on the handlebars - does it still creak? if the creak stops, the issue is the handlebar/stem joint, or the stem/steerer joint. Assembly compound will be helpful in either case. if this is the area, you should be able to make it creak by twisting the handlebars while stopped or when moving.

Maybe this will help.

to test just the crank, get on the bike next to a street sign pole you can hold onto... while stopped, stand tall on the pedals. put one pedal forward so the crank arms are horizontal, and bounce your weight on them, then backpedal so the OTHER arm is forward, and bounce your weight a bit again, repeat a few times. does it creak when you do this? if so, its highly likely to be the bottom bracket or the crank attachments, especially if this bike has square taper cranks.

OP might also want to add a few ounces of olive oil to the dinner entre and see if that helps? I know I creak, grind, clank and clack when just walking; no bike required ;-)

When I'm riding it, it sounds like it's coming from between the BB and the front wheel. When I try to cause creaks while off the bike, like in the video, it sounds like it's between the BB and the rear wheel. Go figure. :D I also didn't hear any loud creaks when I spun backwards.

If I squeeze my spokes, they do make a small ping or 'click' noise, but it sounds different from the noise in the video. Are loose spokes able to make a really noisy creaking sound?

Nope, it gets louder as I apply more torque to the cranks.

When I'm pedalling, I get a more high pitched creak that occurs whenever I'm applying torque to the pedals between 1 and 5 o'clock. I don't have clipless pedals, so I'm not sure if they would be noisy when pulling a foot up. When rolling, I get an irregular staccato creak that is a bit quieter (it sounds like the creak in the video). This mainly occurs when I hit bumps, and sometimes when I'm coming to a stop. I've tried oiling the spokes and tightening the skewer, neither seem to make any difference. I've greased the skewer as well. I don't think it's the pedals, as I can get a creak by gripping a crank arm, pushing downwards, and then rolling the bike back and forth.

Afraid so!

I wasn't able to create any creaks by bouncing up and down, but this was because the front suspension was taking all the damage. :p But I could get a creaking noise if I applied heavy pressure to the front-most pedal. Is there any trick to narrowing the possible cause to either the BB or the crank, outside of buying a new one of either?

Thanks for all of the replies so far!

if you're getting one creak each time you put a pedal forward and put significant weight/power on it, then odds are its the crank to BB interface.

the usual solution is removing the crank, cleaning the BB-crank interface, and then reinstalling the crank. assuming this is a square taper crank, the center bolt has to be torqued on pretty hard, like 60 ft-lbs or something. (look it up at the park tools site)

if its the BB itself, well, then it depends on what kind of BB it is. if its a cartridge BB, removing it, cleaning the threads on the shell and the BB, thoroughly re-greasing, and reinstalling, being sure to torque the lock ring on hard enough is usually sufficient.

If one listens to the video, it does not sound so much like a creak but a loud ratchet; I'm guessing the freewheel pawls are skipping.

what kind of Bottom bracket is it sealed or cone and cups ?

+1. Cranks 1st, then if still making noise the BB. If you don't want to buy the tools crank extractor, BB removal tool(s) if it's the BB) then just have a bike shop do it = probably pretty quick job.

I've removed, cleaned and reattached the cranks a few times already, and there wasn't any noticeable improvement. Tried it with the spindles both dry and greased as well!

The BB is sealed and I've already cleaned, greased and reinstalled it once before, and still the creak remained. I'll give it another go at the weekend, making sure the BB is torqued up.

Is it feasible that the crank arm holes have become distorted and that they're the cause?

Chain is getting a mite long for the cranks or cogs?

Had same... ran a couple doses of penetrating oil into the sealed BB.. didn't help... or it took time for that to work. But it went quiet... now I chg'd out the freewheel and have another noise... methinks that older cog isn't mating that well with the IG chain and front crank made for IG.

Any links kinked.. or not rotating as they should? Turn the crank backwards and watch the chain as it goes thru the bottom wheel of the derailer.

When the creak occurs do the crank arms skip forward without moving the bike?

I'm sorry, should not have scanned your original post so quickly. Totally missed that you had already done the cranks and BB. Low probability but I'm wondering about a frame crack. One way to check for that would be to push sideways on the BB directly from the left side with your foot. That effectively stresses the frame similar to when you pedal.

One other better possibility is the joint between right crank and spider is no longer solid (same with chainring bolt/rivet). If that is the problem one indicator would be that it would NOT occur if you disengaged the chain and then stood on both pedals and bounced up and down (turn 180 degrees and repeat). That removes the spider/chainwheel from the equation, as well as the rear wheel.

p.s. It's not the chain, as only a portion of the chain is under tension at any one point, so the noise would not occur reliably by putting pressure on the cranks.

if he's putting more weight on the front pedal while stopped, that WOULD possibly involve the spider/chainrings. and yes, I've had those make creaking sounds when one chainring bolt was a little loose.

otherwise, yeah, it just maybe could be a frame crack, ugh. the one thing thats really not fixable, and quite likely could get worse with time until it fails catastrophically.

Why is a frame crack not fixable? Depends of course on where.. but there's ways.

thin wall tubing will never be the same once its cracked and been repaired. trust me, I know from past experience. steel frames are mostly repairable, although this may require replacing the cracked frame tube and re brazing or mig welding it., but stretched/formed alloy tubes/stays? good luck with that. Carbon fiber? eeeek!

I think you may mean TIG welding there, MIG doesn't work well with thin-walled tubing.

Calfee offer a repair service for carbon fibre frames. I'm not sure how they do it though.