Intermittent click/clunk

alistaird

All,

This is proving to be a very difficult problem to solve. The bike is great for most of the time, I get an occasional clunk from either the cranks/bottom bracket or the cassette/rear derailleur. I have not found it possible to reproduce the clunk. I've been up hills in and out of the saddle without the noise then it will suddenly happen on the flat. Did 18 miles this morning and it happened once. I can feel it slightly in the pedals when it happens.

Anyone got any ideas what it could be?

Thanks,

Chris James

These links should help track it down

http://sheldonbrown.com/creaks.html

http://www.jimlangley.net/wrench/keepitquiet.html

ds690

If it was at regular intervals, I would blame the chain, but since it is only occasional I would think that your freehub body is slipping.

MrChuck

How old/worn are all the bits and pieces? Clunking makes me think bearings, but we might be meaning different things by 'clunk'!

alistaird

MrChuck wrote:

How old/worn are all the bits and pieces? Clunking makes me think bearings, but we might be meaning different things by 'clunk'!

Most of the drive train is new... Stronglight cranks and BB and Fulcrum 3 wheels. Cassette is lightly worn Dura Ace as is the Chain. Rear mech is about 10 years old Ultegra though, front mech is new Dura Ace. Pedals are about 7 years old.

Any thoughts most welcome!

alistaird

Chris James wrote:

These links should help track it down

http://sheldonbrown.com/creaks.html

http://www.jimlangley.net/wrench/keepitquiet.html

Had a look and most obvious one could be the chainring bolts which I will check...

Thanks.

alistaird

ds690 wrote:

If it was at regular intervals, I would blame the chain, but since it is only occasional I would think that your freehub body is slipping.

Thanks for this, but I'm not sure what you mean by the freehub body slipping? Any more guidance, much appreciated...

kettrinboy

sometimes after freewheeling the pawls in the freehub can occasionally not quite engage properly and then when you first put pressure on the pedals you get a crack/clunk noise but then it works as it should, i get this the odd time on all my bikes fitted with a freehub, havnt had it happen yet on my old Raleigh with a freewheel, sounds like thats what it could be, if the chain was about to let go because of a cracked or bent sideplate you would feel it every time the chain did one complete revolution.

ds690

this

kettrinboy wrote:

sometimes after freewheeling the pawls in the freehub can occasionally not quite engage properly and then when you first put pressure on the pedals you get a crack/clunk noise but then it works as it should, i get this the odd time on all my bikes fitted with a freehub, havnt had it happen yet on my old Raleigh with a freewheel, sounds like thats what it could be, if the chain was about to let go because of a cracked or bent sideplate you would feel it every time the chain did one complete revolution.

alistaird

kettrinboy wrote:

sometimes after freewheeling the pawls in the freehub can occasionally not quite engage properly and then when you first put pressure on the pedals you get a crack/clunk noise but then it works as it should, i get this the odd time on all my bikes fitted with a freehub, havnt had it happen yet on my old Raleigh with a freewheel, sounds like thats what it could be, if the chain was about to let go because of a cracked or bent sideplate you would feel it every time the chain did one complete revolution.

Ah hah.... That could be it, would definitely explain why I can feel it in the pedals as well. if it persists and I can't track it down, I'll try swapping the rear wheel.

Any way of fixing it?

Wheelspinner

I agree it's your wheels, but not necessarily the freehub bits. I have Fulcrum Racing 1's and have the *exact* same noise you mention.

My LBS told me that all Fulcrum spokes do this to a greater or lesser extent, where they seat in the hub. They have a sort of lump at the hub end which seats into the slot in the hub Recommendation is to use a tiny bit of lube on that part where the spoke lump (nice technical description, eh? ) is and see if that fixes it.

He also reckons the reason some wheels do it more than others is that the Fulcrum's tend to have slightly more variability in spoke tension from the factory than some other brands, and that the wheelsets which are a little bit tighter, and more importantly more evenly tensioned, creak less.

If you know a really good local wheelbuilder, get them to check the tension on your spokes.

alistaird

Wheelspinner wrote:

I agree it's your wheels, but not necessarily the freehub bits. I have Fulcrum Racing 1's and have the *exact* same noise you mention.

My LBS told me that all Fulcrum spokes do this to a greater or lesser extent, where they seat in the hub. They have a sort of lump at the hub end which seats into the slot in the hub Recommendation is to use a tiny bit of lube on that part where the spoke lump (nice technical description, eh? ) is and see if that fixes it.

He also reckons the reason some wheels do it more than others is that the Fulcrum's tend to have slightly more variability in spoke tension from the factory than some other brands, and that the wheelsets which are a little bit tighter, and more importantly more evenly tensioned, creak less.

If you know a really good local wheelbuilder, get them to check the tension on your spokes.

Thanks, I'll try and lube the spoke 'lumps' on the rear wheel and see if that makes a difference. If not, I'll try and find a decent local wheel builder.

Thanks again...

buder

kettrinboy wrote:

sometimes after freewheeling the pawls in the freehub can occasionally not quite engage properly and then when you first put pressure on the pedals you get a crack/clunk noise but then it works as it should, i get this the odd time on all my bikes fitted with a freehub, havnt had it happen yet on my old Raleigh with a freewheel, sounds like thats what it could be, if the chain was about to let go because of a cracked or bent sideplate you would feel it every time the chain did one complete revolution.

+1 this is my bet

alistaird

AlistairD wrote:

Wheelspinner wrote:

I agree it's your wheels, but not necessarily the freehub bits. I have Fulcrum Racing 1's and have the *exact* same noise you mention.

My LBS told me that all Fulcrum spokes do this to a greater or lesser extent, where they seat in the hub. They have a sort of lump at the hub end which seats into the slot in the hub Recommendation is to use a tiny bit of lube on that part where the spoke lump (nice technical description, eh? ) is and see if that fixes it.

He also reckons the reason some wheels do it more than others is that the Fulcrum's tend to have slightly more variability in spoke tension from the factory than some other brands, and that the wheelsets which are a little bit tighter, and more importantly more evenly tensioned, creak less.

If you know a really good local wheelbuilder, get them to check the tension on your spokes.

Thanks, I'll try and lube the spoke 'lumps' on the rear wheel and see if that makes a difference. If not, I'll try and find a decent local wheel builder.

Thanks again...

I lubbed the spokes and have now done 2 rides, first one clunk, second none... May well have cured the problem.

Thanks.

alistaird

No clunks on the past three rides so I think lubing the spokes has worked. Thanks guys.

on-yer-bike

I have the same noise on brand new Campag Eurus wheels. I thought it was because I hadnt tightened the cassette enough but that made no difference. Maybe the spokes have the same probelem as Racing Ones? However I also hear it occasionally on my Boras which have different spokes.