Knocking 4500c & Other

[seren]

Hi,



On an early morning ride when all was quiet I noticed that my 4500c produces a fairly low sort of knocking/thumping (best I can describe it) noise when I turn left/right on the bike.  



At first I thought I hadnt refitted the rear wheel correctly (as I had just repaired a puncture), the wheel was fine.  I checked the rear shock, it appears in order as did where it connects to the frame and swing-arm, checked the brakes (V's) they too appeared ok, I even loosened them up and I still got the noise.



I then thought it was the swing arm, so took it to bits, checked all the seals, cleaned, regreased, refitted, and I still get this knocking noise.  



Does anyone know perhaps what this might be?  I just finished rebuilding the bike with all new parts - big thanks to Oz-Sub for parting with his CF Noleen x-links - they work a treat.  I cant for the life of me think what is making the noise, i dont think it is anything too serious, it just annoys me, any help is much appreciated.



Oh yeah, can anyone point me in the right direction for new seal kits for the 4500 and for the x-links, the seals as they are now are fine, I figure that it wont hurt to have an extra set, I am based in the UK.  Can someone also recommend a good set of tyres, I currently have a set of Panaracer Trail Blasters on which are fine in dry conditions, but (in my opinion) are horrible even when they are a little bit damp.



Cheers,



Seren

[Old Proflexer]

i had just such an occurance on mine at one time -

turned out to be dry joints in the lower link at the head set - the unit would work fine up and down but that combined with a torquing action when on the bike and turning seemed to make it stick - drove me crazy trying to find the problem (thought it might be my headset)

pulled / loosened all the xlink bolts and greased liberally while checking all the bushings for damage (none),  cleaned out the grease holes, reinstalled and not had the problem since.  i use slick 50 grease but the k2 recommended is a teflon base.

OP

might give it a try and let us know

[seren]

One bit of important knowledge I forgot to add - the knocking/thumping noise is actually coming from the rear of the bike.

Thanks

[numbnuts]

If you want an all round/xc tyre the IRC mythos is a great and economical choice, I used to run the 2.1's and loved em. Moved onto bigger stuff now, mutanoraptor [race] 2.5, great dry but not for wet conditions imo. Not sure about the knocking, could it be thr rear shock?

[Simon]

Hi Seren I'm also uk based,for K2 parts contact CVI www.cvi.co.uk, your 4500 should be very quiet but through the nature of the frame design and material used a small noise seems to get amplified,there is a de-creaking posting in the files section you may find usefull,you could have a look at the front and rear s/arm dropouts,check that they haven't worked loose,they do that from time to time, so far had to re-bond 3 of mine,also as the any noise tends to travel with these frames the noise may be coming from the front,best check the lower link as op suggests,I'm using IRC mythos 1.95 you can get a good deal on these at www.chainreactioncycles.com,Simon  [smiley=nod.gif]  

[proflexGB]

I have a new set of tyres on the way, they are supposed to be ace for the UK conditions, they are *******,  **********.  

If you reply to the two private messages I have sent you and you have read then I will fill in the missing tyre manufacturer and model.

[Carbon_Angus]

as far as your knocking sound.....

if it's from the rear and you notice it when turning, i would look at

your rear hub, spokes (they make funny sounds sometimes, too)

main pivot bolt torque....just a stab at that one

and for a really weird thought...you may have loosened a piece of stray carbon-fibre that was lodged in the frame and turning the bike over(assuming that's what you did) might have dislodged a stray (harmless) piece of carbon. There are ways to get it out.....if that is the case

do you notice it any other time...as in going straight and over a bump, pedaling or not???


the trailblasters are horrible when wet, i run smoke/darts on my Oz bu don't abuse the bike or myself in the rain much anymore.



good luck

[Oz-SUB]

I'm in shock I haven't posted for so long!

I had an annoying little knock, found it to be worn rear shock pivot bushes.  The original Noleen ones are pretty crappy compared to the ones I got from Mojo for the Supergo Fox Vanilla RC.

Since fitting the Fox and with new bushes all is quiet and perfect.

[seren]

Hi all,

Thanks OP and Simon - you both where right - OP -  once I cleaned, regreased, and replaced a bushing on the x-links they cut the noise down.  Simon - one of my rear dropouts was loose - I had it re-bonded and now I get no noise whatsoever from the bike.

Thanks for the suggestion for tyres, I havent actually bought any yet as I have decided to close up shop for the UK winter - too bloody cold for my liking !!! (I come from a tropical climate)

[Old Proflexer]

now you can go back into 'stealth' mode

(i just pulled my whole bike apart down to the ball bearings, cleaned, inspected and properly reassembled.   what a difference - totally silent, totally smooth)


sounds like your main issue was the loose dropout - everyone with a carbon swingarm has to periodically remove the rear wheel and check the dropouts - just the way it is.  as our bikes start aging around the globe, this is going to be happening much more often.
if one is riding a crosslink, keeping the unit properly lubed is a must.

best wishes and congrats on the declunking - be sure to pass on the aid to someone else in the future, be it a tip on serviceing or a flat tire on the side of the trail.

OP

[Matno]

Ah, the old "strip down and rebuild"!!! I need to do that too! My BB has started creaking lately, and there is generally a lot more noise than I can stand (I have a low tolerance for bike noise!)

Unfortunately, my only time to do something like that is my vacation next week, and I'll be spending that with the family in St. Thomas sans bike. Not that I'm complaining...