Serious or not ?

Russman

Hi gang,
Quick mechanical question......
I'm pulling away from a set of lights, putting down the power (ie standing on the pedals !) and there's a loud click and knock from the cranks, almost like I slipped a gear. Anyway after this I'm getting a slight vibration/knock when I'm pushing down on the right-hand crank, not on every pedal turn but very regularly, especially when churning rather than spinning, and particulary if I get out of the saddle.

Obviously I'll need to get it looked at but anyone have any ideas as to what or how serious it may be ?

Thanks

Hail 2 Da Thief

Check the easy things first such as the pedals, chain ring bolts, seat post (you say it's noisy when you climb out of seat). Maybe regrease the pedal threads & then refix them. check that the chainring bolts are tightened enough.
You say you hear a clicking noise. Is it possibly the chain rubbing the front derailleur & the limit screws need adjusting?

Russman

Thanks for that, I'll check the easy stuff first. Pretty sure the noise isn't the chain on the derailleur though, its more like one little clunk/vibration at the bottom of the pedal turn, almost like there is a little tiny fraction of give in the cranks at a certain point.
Will have a closer look at it in the morning with a fresh eye I guess.

SubLuminal

bottom bracket or cassette/freewheel is knackered..

Russman

SubLuminal wrote: »

bottom bracket or cassette/freewheel is knackered..

That's what I'm afraid of alright !

steinone

Doesnt necessarily have to be so, pop into your lbs and get them to tighten the cranks with a long allen key/ crank tool, its a common problem.
If its not that try kinda lye the bike at an angle holding the bars and saddle from the side put the nearside pedal to the bottom and press on it with your foot, the wheels and frame will flex but generally if you hear a noise its the bottom bracket.

Russman

I'll be bringing it to the lbs alright. I took it out again this morning to try figure out what was happening, I think it needs a more qualified eye than my own though ! Not convinved its the BB now, something's definitely not right though, was still getting the vibration / clicking quite a lot, can clearly feel it in the right crank arm, but after maybe 15k or so, the chain started jumping around on the front while NOT touching the derailleur (seriously !), hopping down into the smaller ring, then it started clinging to the chainring and doubling back up on itself, I couldn't see any obvious damage but, to be honest, I could easily miss something.

Lucky for me I was just doing a circle route and was very close to home - LBS it is methinks !

DirkVoodoo

Have you checked if the big chainring is running true?

Russman

It seemed to be, I was able to spin the pedals backwards by hand yet going forward the chain kept catching and, silly as it sounds, I really couldn't see why.

Dr_Colossus

Russman wrote: »

the chain started jumping around on the front while NOT touching the derailleur (seriously !), hopping down into the smaller ring, then it started clinging to the chainring and doubling back up on itself, I couldn't see any obvious damage but, to be honest, I could easily miss something.

As dirk suggests check that the big chainring is running true. Maybe you were between gears when you first applied pressure coming out of the lights and slightly bent one of the gear teeth? Do you get the same problems if running on the smaller front chainring?
Also check that no link on the chain has gone stiff or slightly twisted sideways, if it's not the front sprocket then it sounds like the chain may be slightly twisted or one of more of the links have gone tight.

Crow92

I was having a similiar issue with a clicking noise, once every revolution at the same place every time.

I never really figured out what it was but Yesterday I took apart most of the bike for a really good clean, Got rid of all the grit in the rear derailer/ Totally cleaned the chain and cassette. Then lubed up the chain, gears and the pedals and now the clickings totally gone.

Just a thought

Slydice

OP, I had a similar problem to what you describe.

Brought the bike to a shop and the guy said something like this:

SubLuminal wrote: »

bottom bracket or cassette/freewheel is knackered..

He said that the chain just wears them down over time

Russman

It probably is something like that alright.
The most annoying bit is that the bike is less than a year old and I only had it in the LBS being serviced about 2 weeks ago so I'll be asking a few questions (in a nice way of course). Actually torn between going back to that particular LBS or somewhere else like Joe Daly's.

SubLuminal

Did you find out what it was yet? A veritable gaggle of armchair-bike-mechanic wannabe's (well, that phrase describes me at least) are curious to know

Russman

SubLuminal wrote: »

Did you find out what it was yet? A veritable gaggle of armchair-bike-mechanic wannabe's (well, that phrase describes me at least) are curious to know

I think it describes the level I aspire to !!

Haven't had a chance to bring it to the shop yet, planning on disappearing from the office after lunch to bring it down to them.

Will let ye know how it goes.......

happytramp

My 20p is on a tightened crank arm getting rid of the clicking.