left crank creaking



Robswindon

New Member
Sep 18, 2006
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When cycling my road bike, if there's a little pressure such as going up a hill, or putting a bit more whoomf down than normal, there's a knocking of metal on metal, which I think is comeing from my left crank. In fact I initially thought it was a loose strap clanking on my seat stem. It doesn't seem to have any effect on my power output, but the clanking annoys the heck out of me and my mate. I'm worried that some bearings inside the hub (?) are being chewed up, but it not a grating, just a clunk. Sorry to be so technical and precise. (not)
 
If your BB was breaking down and knocking to the extend of you hearing it ,i would think you would pick up some side to side play when moving the cranks.It sounds like a loose crank but that would also show some sign of movement,
CHECK TO SEE THAT NOTHING HAS BEEN BENT OUT OF LINE
and now knocks as you pedal.
I spent hours adjusting gears once to elliminate a scraping noise and it ended up to be the cage that was bentover about 5mm,not noticible untill i compaired it with a new one.
 
Start with the basics - loosen and retighten your left pedal (remember left-handed thread), then do the right pedal as well.
 
Don't want to highjack the thread but this may address your issue too. I have just experienced the same creaking. Mine was on both sides and only under load. The day before the ride I used CRC Brake Cleaner that comes in an aerosol can to degrease the bike. It works wonders if you haven't use it, anyway, I sprayed directly on both cranks. Then applied some dry lube and let it sit overnight.

About 60 miles into the ride, I got the creaking. My guess is that the degreaser got past the outer seals and degraded the grease internally.

Don't know if you recently "degreased" but that may be one issue. I'm going to take mine apart to regrease and see if it clears up. Any other ideas anyone?
 
Jeff in IL said:
Don't want to highjack the thread but this may address your issue too. I have just experienced the same creaking. Mine was on both sides and only under load. The day before the ride I used CRC Brake Cleaner that comes in an aerosol can to degrease the bike. It works wonders if you haven't use it, anyway, I sprayed directly on both cranks. Then applied some dry lube and let it sit overnight.

About 60 miles into the ride, I got the creaking. My guess is that the degreaser got past the outer seals and degraded the grease internally.

Don't know if you recently "degreased" but that may be one issue. I'm going to take mine apart to regrease and see if it clears up. Any other ideas anyone?
Would guess the powerful degreaser crept in between the crank arms and spindles, removing the anti-sieze or grease on the splines. Bet your BB bearings are OK.

I've gotten a creaking noise out of one or both cranks twice once, about yearly/5000 miles. They seem to lose a little bit of torque when I check with a torque wrench. Any, removing the bolts, respreading the anti-sieze on the ti spindle and retorquing does the trick.

Brake Cleaner or other strong degreasing solvents shouldn't be anywhere near your bike, IMO. That stuff will ruin bearings and chains....not to mention paint finishes. Your bike shouldn't get that greasy anyway, unless you're spraying WD-40 or 5W-30 motor oil on the chain.
 
What is your frame made of? How about your crank? My aluminum Soloist and my carbon campy crank didn't like each other and I had to use plumber's tape on the BB to solve the creak...
 
Frame is carbon and the crank is the carbon FSA Team Issue.

I'm going to check the pedals to make sure they are tight and if that doesn't do it, pull the crank and regrease everything.

I have another century this weekend and the noise really got on my nerves last weekend.
 
Jeff in IL said:
Frame is carbon and the crank is the carbon FSA Team Issue.

I'm going to check the pedals to make sure they are tight and if that doesn't do it, pull the crank and regrease everything.

I have another century this weekend and the noise really got on my nerves last weekend.
Nothing worse than a nasty creak on a century! Best of luck getting it resolved...
 
I'd also check that the pedals are tight and there isn't anything bumping/hitting when you pedal. The bearing in the pedal could be going bad, or the BB could be going. If you have another pedal, swap it out and see if it goes away. If not I would look at the BB.

I haven't worked with a carbon frame, I don't know if it could creak.
 
Hi Chaps - I'll try all of the above - thanks for the input. What's a BB by the way? the bike itself has only done about 500 km (I made the mistake of building it last year), had it serviced last month (they reckoned it was the rear wheel's cassette - hmmm...), it's an aluminium frame and it wouldn't know a degreasinging if one came up and smacked it in the face. I hope i can sort it as my mate is currently insisisting on cycling 30 metres in front of me - it's either the noise or the curries i keep eating. What a jolly nice little community this is. i think I'll stay in touch. Even if there are lots of american spellings.... happy cycling!
 
Sorry, BB is the bottom bracket. It's the bearing the cranks/pedals attach to. You probably have a sealed bearing. If it goes bad you throw it out and buy a new one with the same length, etc. The LBS can match it up for you if that's it. Unlikely at 500km though. I've definitely seen no-name pedals start to creak by then.
 
By all means check pedals, but also check chainring bolts, pedal cleat bolts, seat clamp, seatpost clamp and crankarm bolts, with a torque wrench if available. If you have a one-piece cartridge bottom bracket, the noise may be caused by a tiny amount of movement between the cartridge body and the adjustable cup, which can be fixed with some "Loctite" between cup and body and adequate torquing of the adjustable cup. If you've never messed with a BB before, read up about it beforehand - I imagine that you have if you built your bike.
 
I relay this remote possibility only because it was the cause of my crank noise. My aluminum frame Fuji had the same type of noise. It occurred only on hills or sprints and was centered in the crank. Drove me nuts! My LBS took the crank and BB out and replaced it with a new one just to confirm that the crank was the problem. It still made the noise! Argh! Then they were concerned that the frame had a hairline crack. The end result was they couldn't find the cause.:mad:

Then one morning, as I lay in bed, a thought came to me, could the noise be caused by vibration travelling from or to another part of the bike? The only thing I could thing of was my bottle cages. I had a pair of aluminum, butterfly shaped cages. I went out, removed the one from the seat tube mount and went for a ride. EUREKA! The squeak was gone!!

Not only did I have my quiet riding bike back, but my wife actually bought my reason for getting a pair of carbon fiber cages!:D

Good luck!
 
I was thinking the same thing, that the source might be elsewhere. In my case, I had just put new wheels on so I changed the cassette. I redid everything including the cassette. The nut seemed to be about a full turn, maybe a bit more, loose. I've relubed everything and am going to try again tomorrow. I'm also going to regrease the pedals which I didn't do last time I put them on.

I am really doubting that it is the bottom bracket since it is sealed and I didn't "force" any degreaser in there. Hope it works b/c the creaking is like nails on a chalk board for 6 hours!
 
Jeff in IL said:
I am really doubting that it is the bottom bracket since it is sealed and I didn't "force" any degreaser in there. Hope it works b/c the creaking is like nails on a chalk board for 6 hours!
Sealed BB noise often comes from play between body and adjustable cup - this wouldn't require degreaser penetration.