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'Knocking' noise - full suspension
My Scott Genuis has developed a knocking noise from the rear end. It only happens on the trails and seems worse when the suspension is in full travel mode (it's quite infrequent when the shock is locked out).
When the shock was serviced it had new bushes and bolts installed. I have also check the bottom bracket, greased the seatpost, checked the pedals, brake rotors, cassette etc. I cannot recreate the 'knock' by shaking the bike, lifting the rear end up (as you would expect with a shock mount problem).
Given it is worse on full travel mode and only when the suspension is active, I am thinking this is likely to be a pivot bearing or a shock issue (although the shock had a complete rebuild with mostly new parts only a few weeks ago).
The noise is quite a hollow knock, it definately isn't chain slap or cables banging.
Any suggestions on how I can trace the noise, or what you think it may be?
The bike rides fine and the travel seems good, it is just an annoying noise! Short term solution may be to turn the iPod on while on the trails 
Jonny
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mine has an annoying click when i pedal. ive got a new drivertrain and replaced all pivot bearings. (required replacing, not to cure noise).. still clicks and ill be farked if i can work out where and why..
good luck mate
It can often be the rear skewer. It creaks or 'knocks' under torsional loads.
Grease the threads, the head etc. I have completely re-assembled the rear ends of bikes in the past to find out it was just the rear skewer being a bit dry or stretchy (as it the case with Titanium or hollow steel skewers).
Is it the suspension hitting the seat tude.?
Was happening to a rider I was riding with on the weekend.
Some added air helped.
Freeriding a xc bike is not a good idea.
I think it's the head gasket...
Could be expensive...
I had an annoying click in the bottom bracket area (or so it seemed) that occurred under load, once the bike had warmed up for a km or so.
Changed the pedals, reinstalled the bottom bracket, pulled every suspension bearing out and regreased all those. Still there.
Turned out it was lack of sufficient tightness in the rear skewer.
When you have the bike upright, if you can feel the slightest play when you lift the bike by the saddle it is probably as simple as a loose bolt on one of the pivots. Simple thing to check before you start taking stuff apart.
Thanks all.
No play in the rear end at all when I lift it (and I went round yesterday with the torque wrench and everything there is tight)
I don't think the shock can hit the seat tube, I did all the pressures last weekend so it should be set ok, certainly no marks anywhere to suggest it is hitting.
I will check the rear skewer - I did find it hugely tight at the Convict after LBS had serviced it (needed a screwdriver to lever it open!), so maybe the threads etc are damaged from that?
Jonny
P.s. hope it's not the head gasket!!
Thanks all.
No play in the rear end at all when I lift it (and I went round yesterday with the torque wrench and everything there is tight)
I don't think the shock can hit the seat tube, I did all the pressures last weekend so it should be set ok, certainly no marks anywhere to suggest it is hitting.
I will check the rear skewer - I did find it hugely tight at the Convict after LBS had serviced it (needed a screwdriver to lever it open!), so maybe the threads etc are damaged from that?
Jonny
P.s. hope it's not the head gasket!!
If all of the above are ok I think it has to be the shock.
Don't rule the shock out just because it's been serviced. I've done a bit of work on a few Genius' over the years & despite being serviced the pull type shocks still don't always perform right.
Saying that I also know a good few cases of forks & conventional shocks being returned from a service with knocks & other odd traits such as sticking down & topping out.
Also, the fact that it's ok when locked out makes me even more certain.
Sorry to not have some magic fix solution...
T
Thanks Tony - think I am coming to the same conclusion.
I spent some time this morning riding off curbs trying to isolate different things. I tightened up the skewers a little, no difference.
I can only recreate the noise when the shock is being activated, at no other time does it happen, as such I think there may be a shock issue.
Really annoying as the shock rebuild took 6 weeks by Avanti through Sheppard Cycles - dreading sending it back, who knows when I will see it again?!
Jonny