Whats that noise ?

[ian emmerson]

Recently had a new drivetrain fitted and earlier this week my lbs adjusted the derraileurs and serviced the hubs. All gears now a dream to find although a "crack" type noise occasionally comes from what feels like the front chain rings. Visual inspection appears to show no wear and given only 200 miles since they were replaced i didnt expect to find any.

Its bugging me as to what this could be ?

any suggestions ?

Thanks in advance

 

[Sittingduck]

Is the noise at regular intervals? If so, once per wheel turn, per pedal turn, once every full cycle of the chain? Does it happen when you're in the saddle or only if you're stood on the pedals? Does it speed up if you change to a lower gear?

Answers to these will help narrow it down

 

[ian emmerson]

Whilst in saddle . Occasional "crack" noise. Particularly when applying pressure to the pedals although not at any specific time.
Happened approx 6 times coming home this evening during a 7 mile commute.

 

[buggi]

i had something a bit like this, i thought the front forks were making a "cracking" noise, happened irregularly, and couldn't work out what it was, as inspection of the forks revealed no defect.

took it to the shop, guy said "where's it coming from"

"Front forks" i said, "Definitely the front forks".

Further inspection proved it to be ...




dirt in the seat post.



prob not the same thing, but the sound might not be where you think it's coming from.

 

[Smokin Joe]

i had something a bit like this, i thought the front forks were making a "cracking" noise, happened irregularly, and couldn't work out what it was, as inspection of the forks revealed no defect.

took it to the shop, guy said "where's it coming from"

"Front forks" i said, "Definitely the front forks".

Further inspection proved it to be ...




dirt in the seat post.



prob not the same thing, but the sound might not be where you think it's coming from.

Too right.

Clicks, squeaks and creaks are notoriously difficult to pin down, they never come from where they seem.

 

[Sittingduck]

s'why I asked about the standing / seated thing...
I am guessing this is saddle or seatpost related. I would take the post out and take the saddle off the rails. Clean all the grime out and put it back together again. Put grease on the seatpost before re-installing.

If this doesn't fix it - at least you will have a clean seatpost

 

[ian emmerson]

Thank you sittingduck for your advice.
This morning i removed the post and seat before cleaning and reassmbling with grease on the post. as well as re tightening various bolts, nuts etc.
Commuting to work this afternoon all seemed well until the "crack" happened again. This time though only on 2 occasions.
It defineatly seems like the front chainrings as i felt this through the pedals.
Sort of feels like the chain jumping.

Close inspection of the rings and chain doesnt give any clues either as all seems in order.

Think a trip to my lbs is getting nearer

 

[ThePainInSpain]

I was having a similar thing, but this was at each revolution on the right pedal.

Jet washed the bike today, really gave the front gears a good seeing to.

'Clunch' (a cross between a click and a crunch) now gone, never knew what it was, but seemed to be caused by general crap everywhere.

Our big problem is dust, it gets everywhere. All the air filters on the car have to be replaced every 3 months.

 

[Sittingduck]

Have you tightened the chainring bolts that connect the 2or3 rings together? Have you cleaned the chain recently!?

 

[accountantpete]

When you say "new drivetrain" - what did the LBS replace exactly?

For example if you had a new chain and cassette but kept the old chainrings there could be a problem with wear to the latter.

 

[Crepello]

It's very likely a slipping freehub. It feels like the chain jumping and does gives an unreassuring "crack". The freehub may require a good soaking in solvent, then re-lubing with a thick oil, unless you can open to service it.

 

[ian emmerson]

Your replies are much appreciated.

Less than 200 miles since chain, mech, derraileur, front rings and cables were replaced.

Earlier this week lbs serviced the free hub. Interesting to hear that this has the potential to cause this problem that wasnt their before the service.

Thats got me thinking ???

Thank you

 

[pwh91]

Have you tightened the chainring bolts that connect the 2or3 rings together? Have you cleaned the chain recently!?

+1 to check the bolts - at least, it's a known cause for me since I've had an occasional "crack" under load from the chainring, and it turned out that I needed to re-tighten the chainring bolts. Worth a try since it's quick and painless....

 

[Tynan]

bearing in the BB starting to start to go?

 

[palinurus]

.. re-tighten the chainring bolts. Worth a try since it's quick and painless....

Speak for yourself. I skin my knuckles everytime I go near a chainring bolt.