Strange clunk - any...
 

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[Closed] Strange clunk - any ideas

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No its not my shrunken brain wobbling around in my skull.

On the tandem when going over bumps there is a clunk that is felt rather than heard. I cannot locate it to one area. It feels almost like "topping out" of the fork but the fork has a soft stop for top out and runs a lot of sag anyway

Headset has no play, axles have no play. I can't find anything loose. Its not harsh like metal on metal anyway.

The fork legs have a small amount of play in the bushes but I can't see how this would be it as it happens even on fairly small bumps where I doubt the load comes of the fork altogether.

It doesn't feel nasty and destructive like a hard impact metal on metal but its bugging me

Any thoughts apart from ignore it?


 
Posted : 22/04/2009 9:20 am
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Anything attached via a bracket - lights, seatpacks etc? Mine make one hell of a racket.


 
Posted : 22/04/2009 9:45 am
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Not that rusty spanner - it feels much "heavier" anyway, Feels almost like a loose headset but it aint


 
Posted : 22/04/2009 9:48 am
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It's coming from the front end?

Could it be the headset cup in the frame? (IIRC you had this repaired)


 
Posted : 22/04/2009 9:50 am
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mechs or chain hitting frame/parts?


 
Posted : 22/04/2009 9:52 am
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No sign of the headset cups moving - but its a good idea so I'll have another look. I did ovalise the headtube a while ago but a long insertion headset with locktite bearing fit appears to have cured it


 
Posted : 22/04/2009 9:53 am
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I'm sure you've checked, but your frame's not cracked anywhere is it?
If you're testing it out solo, could it be the stoker seat coming loose?
Loose caliper?
Cracked bar/stem (shudders)?


 
Posted : 22/04/2009 9:55 am
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And it's [i]definitely[/i] coming from the bike rather than from your wife? 🙂


 
Posted : 22/04/2009 10:00 am
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Fork bushings? Tandems will probably be tough on them.
Check frame for cracks? (I hope not, too!)
Wierd QR/Bearing problem?


 
Posted : 22/04/2009 10:01 am
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False teeth clacking? 😉


 
Posted : 22/04/2009 10:04 am
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What forks are they? Have heard of a similar noise being attributed to the spring flexing sideways on compression and 'tapping' the inside of the fork leg on some RS forks.


 
Posted : 22/04/2009 10:07 am
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Is it FS, if so what about the rear shock bushes. They can clunk when the front forks are depressed, if they're worn out.


 
Posted : 22/04/2009 10:08 am
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Its a hardtail - the forks are 'zocchi Z1 lites. There is a tiny amount of play in the bushes.

Hmmmm - time to have another look. I guess its perhaps fork bushes or springs. Would loose fork bushes give a clunk even if the front wheel never leaves the ground?

Ta folks


 
Posted : 22/04/2009 10:36 am
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Julies knitting needles tapping together perchance? 😉


 
Posted : 22/04/2009 10:46 am
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Righteo - really puzzled now.
No play in the fork bushes ( what I thought was play was infact the pads moving in the calipers)
No play in the steering head / headset
No play in either wheel bearing
No movement at the axles
No free play in the damping - no clunk when bouncing the fork
No visible cracks in the frame
Nothing loose
The only play I can find is in the pivots of Julies Thudbuster and in her pedal spindles

The clunk happens whether pedaling or not and whether braking or not any time we go over a large bump. Julie says she can hear it and it sounds like its coming from the back of the bike

Earplugs are the answer I guess I shall ignore it


 
Posted : 22/04/2009 11:13 am
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You got the rack on?


 
Posted : 22/04/2009 11:16 am
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Yup matt - tubus and all mountings tight with no movement when I gave it a good shake


 
Posted : 22/04/2009 11:18 am
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It's haunted. Call an exorcist! 😈


 
Posted : 22/04/2009 11:21 am
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Have you got a loose or cracked rear rack?

Cable slap?

Not the unweighted Thudbuster topping out?

You haven't managed to get dried mud anywhere inside the frame?

If it's not any of those, I'd take it to the local God-Botherer and get it exorcised. 😆


 
Posted : 22/04/2009 11:21 am
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I think the thudbuster topping out is the most likely now. I'll strip the thudbuster and make a soft top out stop for it
Its not the rack or cable slap - its a heavier clunk than that

Exorcism sounds like a good idea


 
Posted : 22/04/2009 11:24 am
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worn seat post.....crappy old frame like that the ali may of worn inside the seat tube so marginal play could cause a resinating clunk(sp?)


 
Posted : 22/04/2009 11:28 am
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You forgot to mention what the prize was for guessing correctly. 😀


 
Posted : 22/04/2009 11:33 am
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Hmmm - possiblity sharki. The captains seatpost also supports the stoker bars so gets a lot of leverage / weight on it.

I shall treat the comment about the "crappy old frame" with the contempt it deserves.

Hows the shoulder?


 
Posted : 22/04/2009 11:33 am
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Rusty Spanner - Member

You forgot to mention what the prize was for guessing correctly. [:D]

A trip down spooky woods on the back seat 😀


 
Posted : 22/04/2009 11:35 am
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I'll hold you to that one next time I'm in the area!

Ms Spanner and myself having a go ourselves during the summer: Either JD in Ilkley or these people:
http://www.tandeming.co.uk/index.php?option=com_content&task=view&id=132&Itemid=181

Probably mentioned it before but I'm really looking forward to it.


 
Posted : 22/04/2009 11:40 am
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No problem Rusty. Enjoy your go on one. laughs per mile


 
Posted : 22/04/2009 11:43 am
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Dunno about the shoulder Teej, not so sore, if anything the other ones more of a concern, couple more weeks then an x ray too tell me if it's knitted back and how close to being able to ride i am.

It's a Dale isn't it?


 
Posted : 22/04/2009 11:45 am
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It is a dale yes - and I think you have the answer - with the clamp loose there is noticeable play and the "clunk" feels right. It would explain why I feel the clunk but julie hears it.

New seatpost time I guess

Hope the shoulders gets sorted - I need plastering done


 
Posted : 22/04/2009 11:52 am
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winner! i actually knew something.......

pack it with grease, that'll keep the noise down..

Lime plaster in the castle innit?

Hopefully i'll be able to still plaster above head height...


 
Posted : 22/04/2009 2:25 pm
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Don't think its lime plaster but not sure. We still need to get the go ahead to do it - will be a couple of months yet. Two walls to replaster plus lots of crackfilling and then a total redecorate

YOu have won a run down Spooky woods on the back of the tandem 🙂


 
Posted : 22/04/2009 2:30 pm
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I thought it was a listed building...thought it may just be the outside that's listed.

Cool, do i need to watch or can i film it?


 
Posted : 22/04/2009 2:37 pm
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It is listed and it includes the interior. However both walls in question have previously been replastered and hacked about so I am fairly sure modern plaster will be OK

You need to sit on the back - thats the prize


 
Posted : 22/04/2009 2:41 pm
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i know i need to sit on the back.......wasn't what i asked 😉


 
Posted : 22/04/2009 2:44 pm
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Filming would be fine. Entertaining even 🙂


 
Posted : 22/04/2009 3:12 pm
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rearward shot, a trail on poo as i shit in fear of my own life...


 
Posted : 22/04/2009 3:17 pm
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Well new seatpost fitted and tested and the clunk has gone - altho I found another very slight one from the fork dampers 🙁

I could measure a difference in the old seat post and the new one - 0.12 mm and the new one was certainly a tighter fit in the frame tube.

Now to strip the fork. serves me right for being obsessive. I can't stand bikes that make a noise. Now where is my anorak?


 
Posted : 29/04/2009 7:47 pm
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8)


 
Posted : 29/04/2009 7:52 pm

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