New cassette, new chain - weird problem

chrisaonabike

Ok, so I've replaced my cassette and chain. Giant Defy 3 2012, all Tiagra, 10 speed.

Now have:

KMC X10.93 instead of Shimano chain.
Tiagra 12-30 - swap new for old.

No other adjustments. This is the second time I've replaced cassette and chain (though with 105 chain last time), it all seemed straightforward. I lined the new chain up against the old, chopped out the right amount based on using the quick link as the final outer plate. Chain length seems fine, plenty of clearance when the jockey wheels are closest to the cassette.

However, now there's a faint ticking in the littlest cog, once per wheel rev. If I wind the pedal backwards, I can see the chain catching slightly once each rev, on the next cog up. I tried adjusting the limit screw a little to allow the deraileur to settle a little bit more outboard when on the smallest sprocket, but it made no difference.

I've tried reverting to the two smallest sprockets from the old cassette, but it's the same. However, the catch is once per wheel rev, so I'm fairly confident it's something to do with the derailleur/cassette setup rather than the chain.

This is a bit outside my minimal level of experience, so I'd be grateful for any suggestions.

geoffh73

When you adjusted the limit screw did you slacken the cable a little?
If you didn't then adjusting the screw probably don't make any difference as the tension in the cable will hold it in the same place

Geoff

Zerotails99

First if all make sure it's caused by a link on the chain.
Now try the barrel adjuster. Loosen or tighten the cable a tiny bit at a time until the gear jumping stops.

The limit screw should only be used to align the jockey wheels to the last and first ring.

rjkflyer

Interesting you mention that winding backwards highlights this.

This suggests that (when you wind backwards) you are witnessing the chain entering the cassette FROM the CHAINRING and is catching on the next smallest cog, as opposed to the normal entry of chain to cassette from jockey/tensioner wheels (where adjustment is most effective).

So, is the 'ticking' in 'normal' (forwards) operation the chain catching the smallest sprocket as it comes off on its way to the chainring? If so, no adjustment of the RD is likely to cure this.

Just trying to isolate whether it's an adjustment issue (where chain is misguided into RD) or alignment issue (where it's misguided coming from cassette to chainring).

Have you had the back wheel out (yes I guess so as you've changed cassette)? In which case it aligned correctly with chain stays. I'd suggest that the 'front' edge of your rear wheel (at seat post) is closer to the RH chain stay than the left...?
Am I making sense?

chrisaonabike

RJKflyer wrote:

Interesting you mention that winding backwards highlights this.

This suggests that (when you wind backwards) you are witnessing the chain entering the cassette FROM the CHAINRING and is catching on the next smallest cog, as opposed to the normal entry of chain to cassette from jockey/tensioner wheels (where adjustment is most effective).

So, is the 'ticking' in 'normal' (forwards) operation the chain catching the smallest sprocket as it comes off on its way to the chainring? If so, no adjustment of the RD is likely to cure this.

Just trying to isolate whether it's an adjustment issue (where chain is misguided into RD) or alignment issue (where it's misguided coming from cassette to chainring).

Have you had the back wheel out (yes I guess so as you've changed cassette)? In which case it aligned correctly with chain stays. I'd suggest that the 'front' edge of your rear wheel (at seat post) is closer to the RH chain stay than the left...?
Am I making sense?

Perfect sense - thanks for coming back on this. It's catching as you say - I even wondered if the cogs were machined right, and tried the ones from the old cassette, but it made no difference.

I've just taken the following video of the chain as it catches on the next smallest cog, while I wind the pedal slowly backwards. The main catch is once per cassette revolution.

http://youtu.be/owojSib81EI

Hope it sheds some more light on the problem - I've got the Ride London on Sunday!!

smoggysteve

Have you got the chain facing the right direction? Yes chains are directional. If you look at the teeth. They are all different lengths and shapes. This is designed to help gear changes. The chain needs to be on the correct way. KMC and Shimano chains have a direction of travel to them so these teeth catch the chain correctly. If you find one particular tooth is catching its likely to be this. It is only noticable on the smallest cog because the diameter is smaller and makes the angle of pick up more acute

chrisaonabike

SmoggySteve wrote:

Have you got the chain facing the right direction? Yes chains are directional. If you look at the teeth. They are all different lengths and shapes. This is designed to help gear changes. The chain needs to be on the correct way. KMC and Shimano chains have a direction of travel to them so these teeth catch the chain correctly. If you find one particular tooth is catching its likely to be this. It is only noticable on the smallest cog because the diameter is smaller and makes the angle of pick up more acute

Is this definitely right?

The chain i bought was this KMC X10-93, which specifically says non-directional on it.

smoggysteve

One side if flat and the other has tapered lips on the links. Them lips work in conjunction with the shapes on the teeth.

chrisaonabike

SmoggySteve wrote:

One side if flat and the other has tapered lips on the links. Them lips work in conjunction with the shapes on the teeth.

Sorry, I don't get this. What part of the link is the lip?

Is there a way of telling just by looking?

arlowood

Just an observation from your video - the normal convention is to have the QR release lever on the non-drive side. Makes it a bit easier to operate away from the crud and mechanics of the rear derailleur/cassette.

To address your chain issue it does seem as if the chain is marginally too far in-board when on the smallest rear cog. I would agree with the comment above that your attempt to adjust the limit screw was probably negated by having the rear shifter cable attached.

Try going back and doing a full rear derailleur set-up with the cable unattached - ie reset the outer and inner limit screws as suggested in the Shimano Tech docs.

file:///C:/Users/Walt/Downloads/DM-RD0003-03-ENG.pdf

Then attach the cable and reset the indexing as shown here:-

https://www.youtube.com/watch?v=SkzvfCaIbyQ

keef66

Your chain looks OK to me. It isn't directional.

Has your QR lever always been on the drive side of the bike? I'm wondering if it's somehow interfering with the rear mech.

chrisaonabike

arlowood wrote:

Just an observation from your video - the normal convention is to have the QR release lever on the non-drive side. Makes it a bit easier to operate away from the crud and mechanics of the rear derailleur/cassette.

Dear god, I did know that, the only thing I can imagine that possessed me to put it back in like that is that the bike was upside down, and I was too tired to notice... what a complete spanner... :oops: :oops: :oops: :oops: :oops:

Thanks for pointing it out... I'd probably have noticed next time I took the wheel off but even so... :roll:

To address your chain issue it does seem as if the chain is marginally too far in-board when on the smallest rear cog. I would agree with the comment above that your attempt to adjust the limit screw was probably negated by having the rear shifter cable attached.

Try going back and doing a full rear derailleur set-up with the cable unattached - ie reset the outer and inner limit screws as suggested in the Shimano Tech docs.

file:///C:/Users/Walt/Downloads/DM-RD0003-03-ENG.pdf

Then attach the cable and reset the indexing as shown here:-

https://www.youtube.com/watch?v=SkzvfCaIbyQ

Righto, cheers

chrisaonabike

keef66 wrote:

Has your QR lever always been on the drive side of the bike? I'm wondering if it's somehow interfering with the rear mech.

No it hasn't. I'm an eejit. :roll:

However, it will be back on the non-drive side presently

Old_Timer

Chris, just a thought, if the KMC has a quick link connector, make sure it is completely locked in and not slightly out of the locked position. I had this issue you describe with a SRAM 1090 chain, SRAM 1070 cassette and Rival RD, recently. The quick link was just slightly out from the locked position and it would lift up slightly as the quick link entered the RD or the teeth of front or back. Snapped it completely closed and the problem went away.

Best of luck with solving the problem.

chrisaonabike

Old_Timer wrote:

Chris, just a thought, if the KMC has a quick link connector, make sure it is completely locked in and not slightly out of the locked position.....

Best of luck with solving the problem.

Cheers for this, actually this was the first thing I checked.

I don't think it can be this though, since the chain catches exactly once per sprocket revolution, which is far too often for the quicklink to go all the way round and back in again.

Old_Timer

Well then, no other ideas from my empty brain chamber :roll: , hope that it gets solved quickly, Cheers.

chrisaonabike

arlowood wrote:

To address your chain issue it does seem as if the chain is marginally too far in-board when on the smallest rear cog. I would agree with the comment above that your attempt to adjust the limit screw was probably negated by having the rear shifter cable attached.

Ok, I've had another look with the cable completely disconnected.

With the chain on the smallest cog, I turned the top limit screw two full turns anticlockwise. The RD didn't move significantly, and the catching was the same.

I've turned the screw back to where it was (two full turns clockwise), and again, no difference.

Completely puzzled now.

keef66

If the mech doesn't move far enough with no cable and the limit screw unwound, it suggests the mech hanger might be bent. Has it ever crashed or fallen drive side down?

jgsi

just a footnote to this.. have been experiencing a run of 'bad' KMC quicklinks of late.. 10 speed... hard to install and almost impossible to remove without a chainbreaker and becoming stiff when used causing chain click.. previously have had nay issues with installing and removing.
Using an old Connex link at mo... these sods are directional ..

chrisaonabike

keef66 wrote:

If the mech doesn't move far enough with no cable and the limit screw unwound, it suggests the mech hanger might be bent. Has it ever crashed or fallen drive side down?

Not as far as I know. And certainly not since I swapped the cassette and chain over on Saturday.

I'll take a photo of the mech/chain from behind and post it... it looks pretty straight to me, certainly at the bottom. Slightly closer to the top of the 2nd cog, but that's to be expected, since the route from the top of the cog to the chain ring is not in the same plane as the smallest cog.

chrisaonabike

Ok, here's what it looks like from behind... pretty much bang in line to my eye, let me know if you spot anything obvious. I'll do another from the side...

chrisaonabike

Update:

Just took it down to my local Giant shop (it's a Defy 3 composite, 2012, Tiagra), and they took a look... then they took the mech off and put a hanger alignment gauge on it. He reckoned it was very slightly bent, and unbent it. Then he indexed the gears and pronounced it Ok....

.... despite the fact that the original problem was still in evidence. Only when turning the pedals backwards though. The ticking in top gear seems to have stopped.

I'll go out for a short ride on it tomorrow - see what it's like. Other than that, I'm out of ideas, other than it's just a slight difference between the old Shimano chain and the new KMC one.

rjkflyer

What's that thing wrapped around the seat stay that appears to be obviously rubbing the chain??!!!

chrisaonabike

RJKflyer wrote:

What's that thing wrapped around the seat stay that appears to be obviously rubbing the chain??!!!

It's a good question, I wondered if someone would ask

It's the elastic band holding the Crud mudguard stay. I've moved it up a few mm now - not because it was causing the chain problem (it wasn't) but because when the chain catches, it pops up a bit and only then just touches the elastic band.

I don't want it wearing the band through, and then have the mudguard come off and get graunched into the spokes!

The chain is definitely catching on the next cog up the cassette, but always in the same place. The angle from the smallest cog across to the big chain ring is just enough to have it foul slightly on that second cog, which lifts the chain before it pings back down, as in my video.

I suppose in theory the new chain (KMC) might be a little wider than the old one (Shimano), but I'd have thought KMC would have compatibility completely sorted.

keef66

I had a brief flirtation with some Mavic 10 speed chains that one of the online retailers was selling off suspiciously cheaply. They were clearly a tiny bit wider externally then the 105 chain I'd been running, and as a consequence were a lot noisier even with the indexing spot on. Probably didn't do the cassette any favours running them either.

gloomyandy

I realize doing this is a pain, but have you tried putting the old cassette back on? It could be that the new cassette rather then the chain is the problem (maybe some excess metal on a tooth, or slightly bent or whatever)?

mamba80

I ve used a kmc 10 sp chain on a 105 cassette without issues but I did wonder that the b screw looks like its screwed in a lot, I ve run a 34 mtb cassette and used less adjustment.

also, the H screw adjustment should move the RD out board quite a bit beyond the smallest cog, there is about a 2mm float on the top jockey wheel, I think you should loosen the H screw about 1/2 turn, you can slacken the RD tension adjuster it the mech doesn't move but I would expect enough cable slack to still allow the mech to move slightly.
it is also possible the shop haven't done a great job with the realignment but as it was ok before, then this shouldn't be the issue, as you ve swopped cogs, the next step would be to try a shimano chain?

Nairnster

Is it definitely a 10 speed chain? As the name seems ambiguous

chrisaonabike

gloomyandy wrote:

I realize doing this is a pain, but have you tried putting the old cassette back on? It could be that the new cassette rather then the chain is the problem (maybe some excess metal on a tooth, or slightly bent or whatever)?

I tried putting the smallest two cogs from the old cassette back on, it made no difference.

chrisaonabike

Nairnster wrote:

Is it definitely a 10 speed chain? As the name seems ambiguous

It's one of these.

Nairnster

Fair enough, wondered if it might of been boxed wrongly.

Have you tried slackening off the b angle screw a little?