Pedal Rotation - funny noise

Raam

Hey there,
a few weeks back I had a chain problem, so I got a new one and the bike was running very smooth for a few days. Then last week I started noticing that at the same point in my cadence I am hearing a creaking/clunking sound whenever I apply a bit of extra pressure to the pedals. I think that maybe there is something amiss with my bottom bracket rather than with the chain since it seems to be at the exact same point in the rotation.
The bike is probably due a service anyway, but I'd like to have an idea of what work needs to be done before I bring it into the shop, and maybe there is something I could do myself to fix it. Might it just need a bit of oiling or something?
Anyone have any pointers?
ta,
KR

happygoose

Sounds like the BB alright. You should post the same thread to bikeforums.net and cyclingplus.co.uk

crang

i would say it is the ball bearings at the end of the pedal stem

Johnny Jukebox

Its probably the bottom bracket. Grab the crank and see if there is any lateral movement in it. If there is, its worn and time and replace.

Less likely is the pedal bearings. This is more obvious as you can feel it under your foot, whereas the BB problem feels more remote.

Replacing a BB is tricky enough. You usually need special tools, both to remove the cranks and then extract the BB. The BB is well embedded and mine have always needed lots of persuasion to come out. Make sure the replacement BB is the same length (overall and BB shell) and the same spline as your cranks.

Capt'n Midnight

It could also be your knee

check the cranks too - if you have toe straps try lifting on the other side at the same time - if no noise then crank or pedal. Have the cranks ever been tightened to the bottom bracket axel ? Pedals tend to self tightnen due to left hand thread and stuff.

Raam

I've only noticed the noise since I threw on the new chain, probably a coincidence. There doesn't seem to be any lateral movement with the crank. I don't think it's the pedal, it feels like it is coming from further down, which thankfully rules out my knee That said, I tried to remove the pedals at the weekend and they wouldn't budge. Will loosen em up with some wd40. I'll do a more thorough investigation tonight, but I reckon I'll have to bring it to the shop to sort out as it is getting annoying listening to the fecker

Capt'n Midnight

you say new chain, so I take it you have looked at the derailer when the chain runs backwards to see if it jinks when a stiff link goes through.

was it Von Neuman who had a broken tooth on the chainring and a stiff link and used to count the cadence then stop the bike and move the chain on because it would always come off at that point otherwise ?

Raam

Capt'n Midnight wrote:

you say new chain, so I take it you have looked at the derailer when the chain runs backwards to see if it jinks when a stiff link goes through.

that was the first thing that I checked. It looks OK to me. The noise seems to occur at the same point in my cadence no matter what gear I have it in, usually (depends how much pressure I apply) just as I start the downstroke with my left foot. So I reckon that would point to a crank/BB problem rather than the chain.

KR

Citizen_Erased

I duno i this is in any way related but my brothers ralleigh had a problem that sounds like that. I dont know any technical stuff but ill explain best i can . The hole that the central bar goes through the crank and the screw is put in over very little time became worn away and the hole was not perfectly shaped as a result. This meant the pedal clunked at the same point every rotation. And then it just kept getting worse and worse until y'know. It has even done the same to a replacement