Clonk! (1 Viewer)

[Dodgey]

Any clever bike types here???:thumb:

This is the bicycle bike, most of the time the faster/more load applied to the peddles produces a rythmic CLONK (caps 'cos it's loud!) that sounds kinda like some loon following me a belting the frame with a lump hammer.

It sounds most like it's coming from the rear gear assembly, 7 speed/gears and I can feel it through the frame but nothings touching/fouling anywhere. Bikes only a couple of years old, any thoughts?

 

[Terry]

Hi it sounds like the gudgeon pin is loose or worn (holds pedals in position) take off the pedal arms examine grease and replace.:thumb: of course I could be wrong
terry

 

[Geo]

First point of call is the pedal crank bearings, rock pedals to test, there should be no play, even if there is no play it could be the early signs of bearing failure, play will eventually become evident, cant think of anything else that would cause a heavy CLONK as you describe
Geo

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[Andy 01424]

Or the Chain is slipping on the gears if this happens during change and keeps trying to go to nex gear:thumb:

 

[Dodgey]

Terry,

Gudgeon pin?....Cotter pin, it's the other type (can't remember what it's called) but no can't be that, mad push biker in my youth and remember the cotter pin shenanegans well, one bike just ate 'em, never did figure out why...

Geo,

Crank bearings, doesn't sound as though that's where the problem is though I must admit that was my first choice. No decernable movment as yet, might have to bite the bullet and strip the bugger and see. It's only a cheapy but I don't really want to replace at the mo, still seeing exactly how much use it's going to get as to how much to spend next time, that and have you seen modern bikes, hydralic disk brakes, 27 gears, adjustable suspension, toys toys toys:thumb:

Cheers for the replies guys, any more?

 

[Dodgey]

Or the Chain is slipping on the gears if this happens during change and keeps trying to go to nex gear:thumb:

Good idea but no chance, anal here has the gears set perfect, no slip and bang on adjustment.

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[johnsandywhite]

Hi Dodgey. I have the same problem with the Mountain Bike I bought from Walmarts 4 years ago. It has almost always done it. I believe it is the Crank Bearings. When I run Oil into the Crank it quietens down for a period before the sound returns.

 

[Terry]

Gudgeon pin?....Cotter pin OK I will settle for cotter pin :thumb:
either way it looks like you are going to have to strip it down like it or not oh:
terry

 

[old-mo]

If it is more or less every revolution of the peddle,, most probably what used to be the cotter pin,,, but on modern bikes you have an allen key on the end of the shaft (Pedal crank arm),, these are splined or square,, might need nipping up,, if it is the spline type whip it off as if it has been doing it for any length of time a splines might be worn on crank arm,,

Modern bikes the cranks are alluminium and the shaft is steel,, hence the splines being/getting worn.

The other alternative, on your gear wheel/cluster,,, if it happens in a particular gear,, it may have a crack on the thread on one particular gear wheel... 5/6/7 gears are made up of individual gears/teeth and they in turn are threaded onto a rachet body,, so you can remove sets of gear teeth and put what ever combination of gearing on that suits you,,
If I remember correctly the threads are the oposite of the norm,, so as you do not unscrew when peddling.. bear this in mind if it is this and when replacing gear,,

Think they are that cheap if it is this probably not worth the bother and just buy a new complete set..

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[old-mo]

No there not,,, "Normal Thread" oh:

 

[mondo]

Remove the pedal crank and check the spindle you possibly have a cracked spindle..if not pack it with grease that should cure it

 

[Frank772]

May be worth looking to see if the L/h crank is bent (by dropping the bike) and
hitting the chain stay.

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[johng]

seems a harsh way to check that, Frank welcome

I would have said bottom bracket bearings, or what is now in place of the gudgeons, usually a square shaft that now has worn cranks on..

as said above a few times

 

[John H]

It could be a damaged or kinked link on the chain, or a damaged tooth on the crank?

John

 

[Frank772]

seems a harsh way to check that, Frank welcome

I would have said bottom bracket bearings, or what is now in place of the gudgeons, usually a square shaft that now has worn cranks on..

as said above a few times

Sorry I should have written caused by dropping the bike
:Blush:

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[johng]

no worries

sorry for being silly :thumb:

 

[pappajohn]

chuck it in a skip and buy a TOAD !!!!!!!!

 

[Geo]

Sorry I should have written caused by dropping the bike
:Blush:

Welcome to the FUN site Frank, it made me smile, written like a seasoned Funster :thumb:
Geo

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[Frank772]

Thanks Geo, I've also remembered that a gudgeon pin holds
the piston onto the conrod oh:

 

[cyclingdoglucy]

bottom bracket

just a educated guess is that the bottom bracket wants removeing & a sealed bottom brkt put in its place. you will have to remove the cranks & one of the bottom brkt cups has a left hand thread/oh:

 

[Dodgey]

chuck it in a skip and buy a TOAD !!!!!!!!

Daft bugger


The gold stars are looking like going to the crank bearing camp. Stripped down and piece of randon plactic in there, nothing to do with anything, next to no grease, rough bearings and some wierd 'lumps' on one of the bearing cups...

New bearings, a quicky with the die grinder/oiled wet and dry and new grease and hopefully smooooth piece and quiet again.

Cheers all!:thumb:

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[Geo]

First point of call is the pedal crank bearings, rock pedals to test, there should be no play, even if there is no play it could be the early signs of bearing failure, play will eventually become evident, cant think of anything else that would cause a heavy CLONK as you describe
Geo

Told Ya