RST - Plauged with noise

[goosander]

My RST had a persistent creak from the eccentric bottom bracket which has been driving me nuts for about the last 3 months.  At the weekend I was going to give the chain a good clean but realised that it was getting towards the end of its life (only 2800 miles, disappointing) so decided to replace it instead and move the EBB to a new position in the hope of getting rid of the creak.

I fitted the new chain and also took the opportunity to remove and clean the rear sprocket and grease its threads with copper grease.  The good news is that the bottom bracket creak is gone for the time being but it has been replaced with a loud "zzzzz zzzz" grinding sound (hard to describe) when applying anything other than a light load to the pedals.  I don't think anything is wrong as such, rather the sound is normal hub noise somehow being amplified/resonated by the new chain.

I'm hoping that the noise will quieten down as the new chain beds in, but am wondering if anyone else has experienced something similar after replacing only the chain (sprocket & chain ring didn't look worn).  

Is it possible that I've screwed something up by removing & replacing the sprocket - it seems straightforward enough other than the force required to remove it.

[paulhipwood]

Sometime ago I had a noise that would not go away. After trying all sorts off changes I reversed the chain.
The noise then went away!!!!
worth a try?

[freddered]

Most noise from my RT came from refitting my chain the wrong way.  I guess this has the same effect as a new chain.

Did you refit sprocket the same way around?  All these things are really best done at the same time as they tend to bed-in together.

2800 miles seems too early to fit a new chain.  What was wrong with it?  unless it's actually broken I'd remove a link and refit it.

[goosander]

Reversing the chain is certainly worth a try, but I'd be surprised if it made any difference, it being a new chain.  I think I'll also try refitting the old one to confirm that the grinding noise is indeed linked to the new chain.

Unfortunately the creaking/clicking noise from the EBB has returned, I really don't know what to do about this other to try tightening the set screws a bit more.

Freddered - I refitted the sprocket the same way round it was originally.  I decided to replace the chain because it was approaching 1/8" elongation over 12" which is the point at which many people recommend replacing the chain to avoid prematurely wearing the sprockets.  Surely if a chain has stretched enough to require a link to be removed, then it must be extremely worn?

[PH]

quote:Originally posted by goosander


Unfortunately the creaking/clicking noise from the EBB has returned, I really don't know what to do about this other to try tightening the set screws a bit more.

I can't think what that could be unless it's the BB itself and you can normally feel when they're not right.  Maybe try removing the EBB, cleaning the shell and adding a touch of grease.
 

quote: I decided to replace the chain because it was approaching 1/8" elongation over 12" which is the point at which many people recommend replacing the chain to avoid prematurely wearing the sprockets.

In theory, yes.  Except if you're not careful you'll spend more on chains than you would if you had to replace a worn sprocket.  They're only £25 and unlike a cassette, reversible.  Also some chains wear very fast to start with and then settle down, my present chain needed adjusting weekly 3 or 4 times then hasn't needed touching for at least a month.
 

quote:Surely if a chain has stretched enough to require a link to be removed, then it must be extremely worn?

Depends, if you started with the EBB in the middle position you'd run out of adjustment before reaching the 1/8 over 12 rule.

[goosander]

quote:Originally posted by PH

I can't think what that could be unless it's the BB itself and you can normally feel when they're not right.  Maybe try removing the EBB, cleaning the shell and adding a touch of grease.

I dismantled and cleaned and greased everything about 3 months ago in an attempt to resolve the problem.  Usually the clicking is silenced for a couple of days after repositioning the EBB.

quote:
In theory, yes.  Except if you're not careful you'll spend more on chains than you would if you had to replace a worn sprocket.  They're only £25 and unlike a cassette, reversible.  Also some chains wear very fast to start with and then settle down, my present chain needed adjusting weekly 3 or 4 times then hasn't needed touching for at least a month.

PC48 chains are only a £5 if you shop around.  Do you just run your chain, sprocket & chainring in to the ground and then replace (or reverse) the lot together?  If so what sort of mileage would you expect to get from them?

quote:Depends, if you started with the EBB in the middle position you'd run out of adjustment before reaching the 1/8 over 12 rule.

Hadn't thought of that.

[stutho]

Hi goosander,

quote:Do you just run your chain, sprocket & chainring in to the ground and then replace (or reverse) the lot together?

That is exactly what I do on my RST, I am on about 7500 miles on my first chain I will sort out the lot at about 12,000.  I would recommend switching back to you first chain!  

Going back to your original problem, the clicking - what cranks are you using?  Any possibility of swapping the cranks with another bike so as to eliminates some of the variables?

[geocycle]

Hi Goosander, I had a real problem with an irritating click on each revolution from the BB area some 1000 miles back.  I changed the chain, adjusted the EBB as described above, and the problem stopped but within a few days it returned.  Eventually, I stripped the cranks off and removed the EBB completely.  I was going to remove the BB from the eccentric but couldn't shift it.  Close inspection of the EBB suggest that some of the holes made by the bolts were too close together and had made one larger hole so that the EBB shell was moving slightly when under pressure.  I had adjusted the EBB too often to keep the chain tension high.  Anyway, I refitted everything with lots of grease and ensured that the bolts made new holes.  I haven't had a problem since....  I have now decided not to touch the EBB until the chain falls off!

[goosander]

Stutho - So effectively you will be letting the chain wear way beyond what is normally acceptable on a deraillieur bike?

I think I will do as you suggest and go back to the original chain.  I could borrow the cranks off my spare bike but I really don't think they are the problem since the clicking noise does generally disappear for a couple of days after adjusting the EBB.

My theory is that pedalling force is causing the EBB to move or rock slightly which is causing the clicking sound (it happens twice per crank revolution).  I suspect that either the set screws are loosening slightly (might try some thread lock) and allowing a slight movement, or possibly the dent in the EBB shell is becoming enlarged slightly again allowing movement.

One other possibility is that I need a new EBB shell - the first time I adjusted it I didn't tighten the set screws sufficiently and after a few days the EBB moved significatly causing the dent in the shell to become elongated and also scoring a pair of 'tracks' in to the EBB shell.  I now have to make sure I avoid the elongated dent when adjusting.

[stutho]

quote: Stutho - So effectively you will be letting the chain wear way beyond what is normally acceptable on a deraillieur bike?

Correct on a derailer you are swapping out the chain early to protect your cluster from damage but on a SS (or a hub gear) there is NO advantage swapping out a chain that early.  When you do eventually swap the chain the chainring and spur gear need to be reversed / swapped.  Note that because your chain is now going to be on you bike for two or more year, rather than 6 months, it is worth getting one with a nickel finish (to deter rusting which will eventually happen even on a well oiled chain if you ride in all weathers).  I use a SRAM PC68, which works nicely.

[goosander]

Fair enough, though I am now questioning whether it is worth trying to protect the cassette on a deraillieur bike unless you are running very high end expensive kit, bearing in mind the cheaper cassettes are under £20 - may as well run until the chain starts slipping or the gear change suffers.

[goosander]

I decided to go back to the original chain and spent half an hour cleaning it in paraffin, only to find that it was too short - I'd forgotten that I had cannibalised it to fix the chain whip that broke twice whilst attempting to get the sprocket off.

Look like I either live with the noise or reverse the sprocket early [V]

[PH]

quote:Originally posted by goosander

Fair enough, though I am now questioning whether it is worth trying to protect the cassette on a deraillieur bike unless you are running very high end expensive kit, bearing in mind the cheaper cassettes are under £20 - may as well run until the chain starts slipping or the gear change suffers.

 There are some who would advocate just that, though it's not quite as clear cut as with a single sprocket. With a constant chainline everything will continue to work fine till the teeth are just about worn away.  Each sprocket of a cassette is thinner and shaped to ease shifting, as you're likely to spend most time in the same 2 or 3 they'll wear pretty quickly with a worn chain.  That wear will also affect shifting long before it’d give trouble on a straight chainline.
I have in the past, on my Ravens derailleur predecessor, bought cheap components and run drivetrains into the ground.  Middle chainring, cassette and chain would need replacing around 3 - 4,000 miles (though it would probably start playing up before then) at a cost of about £40.  My only present derailleur gets looked after and I like it to look just right. I use decent quality components, take the chain off to clean it, change it at 1/8 over 12 and even buying in bulk at York Rally, it still costs more!  The only advantage is it always runs and changes smoothly.

[goosander]

I phoned up Thorn to get their advice, and they have suggested greasing the EBB with copper crease rather than normal grease, so I'll give that a go and see if it helps.  I've also borrowed a torque wrench to make sure the set screws are tightened correctly - it looks like I haven't been tightening them enough.

I have also spent time filing the sprocket to remove slight hooking from the teeth which seems to have helped a lot with the chain noise, hopefully it will get back to normal with a few more miles.

[stutho]

Copper grease is great stuff I use it everywhere on the bike that isn't required to be slippery.  Among other locations it is on my bottom bracket to EBB interface and on the EBB to frame interface it is also on the cranks to BB interface and on pedals to cranks threads. I think that it is so important I take a small tube of it on tour (and a small tube of lithium grease as well).  

Filing off the burs occasionally on both the chain ring and sprocket is a good idea BUT BE CAREFUL that you know what to file and when to stop.  It is one of those jobs that never really needs doing but some of us bike geeks do it anyway!  

I hope I haven course offence. Apologises if I have.

Stuart