this is a bit difficult to explain, so apologies for the poor explanation before I start.

I've got an slight creaking / knocking sound coming from my cranks and / or bb. I can only hear and feel it at low speed. I can make it happen by pushing hardish on my left crank, it makes the knocking sound at about the 9 - 10 o'clock position, then it also does it on the right side too (around the same position). I have checked and the crank bolts are all done up nice and tight and the cranks themselves are also tightly done up. My chain isn't too tight, so I don't think that is causing it.

My main concern is that there might be something wrong with the bb, which was new at easter that will damage the cranks (also new then). It's been like this for about less than 2 weeks.

does this sound familiar at all to anyone? any advice is much appreciated. I'll try to think of a better description and update this if I can.

you might have got some water ingress into the bb, and if it's a cheap one that can cause some creaking.

have you taken the cranks off, taken out the BB, the cleaned and regreased the whole lot? often does the trick.

I had the exact same problem a couple of months ago. In the end I took the bottom bracket out, cleaned everything up, greased everything up and installed. Bingo!

see? what i said. and what he said. job done.

have you taken out a BB before?

I did get pretty soaked a few weeks ago, so maybe I did get some water in there. I've never taken a BB out, I assume I'll need a specific tool? It is something I'd quite like to give a try though. Only downside is I'm not graced with a great selection of tools or knowhow.

Chainring bolts can be bastards too. Spend way north of £100 on Sugino 75 cranks and (now I've discovered) you are supplied with the shittest bolts on earth.

total piece of piss, easy as hell.

find out what cranks, what BB you got then get back on here and i'll lend you the tool, or if i've not got it, someone else will.

i've got tools for cup and cone axles and shimano cartridge ones. I'm down Brixton way.

i got campag and shimano tools, but not for the big round teethed ones. i got campag crank puller too.

maybe its your knees?

It could be the pedals too.. I just checked the BB-7400 on my Vivalo since it has a weird clicking-sound, not coming from the BB, and not coming from the chain ring bolts, it must be the pedals.. which is annoying since they are 540 SPD's and the 2 sets of 520's I use does not have that problem ;)
Apparently cheap is not always worse..

i haven't had a pick of trouble from the three sets of 520's I've owned.

worth having a close inspection of your frame for cracks if you can hear a creaking noise - it would fit your described symptoms

i've got a crank puller and shimano/campag bb tools too, in camden. i'm around all the time at the moment, so just pm me if you need to use them.

I got it from BLB before I had any degree of bike knowledge what so ever, so knowing my luck you're probably right. I'll have a good look tonight, and keep my fingers crossed.

I'm not sure what BB I've got, but I know it isn't a miche (they didn't have one available and had chucked the box and couldn't remember the part when I picked it up). My crank set is a miche advanced.

does anyone fancy giving me a lesson in how to extract and install a BB and cranks? I'd be eternally grateful, and you'd be rewarded in beer. can do any night this week except tomorrow, going to see Radiohead in Victoria park (whoop).

It might well be my imagination, but I think it's getting worse.

There seems to be a bigger gap between the BB cup and the frame on the left than on the right, would that suggest a poorly fitted BB that maybe be causing the knocking? I've attached a few pictures which might help (sorry for the camera phone quality)...

from those can anyone tell what tool would be needed to get it out? my bike knowledge is getting better, but i'm still a veritable novice, so sorry if any of the above is stupid! That's why I could do with the instruction of someone who knows what they are doing.

cheers.

Looks like you just need to tighten your BB cups. Even the most minute bit of play can be felt under load at certain points in the pedal stroke.

EDIT: If it's a fairly recent purchase, BLB should just tighten them for you for free while-you-wait (best give the shop a call to say when you'll be dropping by).

frame was BLB, BB etc was Cavendish. I'll give them a call and see what they think.

Also check the threading on the pedal axle hole (sorry I don't know the correct terminology). I had creaking in my left crank, when I came to change pedals for whatever reason, I noticed there was very little thread left in it, meaning the axle wasn't in securely.

Needless to say, I replaced the left hand crank and it's fine now.