mechanical issue

[Tilt]

Hi guys

I have replaced chains before and have been considering a new middle ring for a while before now.

I purchased a new 9 speed KMC chain recently @ £16 from online bike shop after using one (KMC X9 SILVER) before and it giving me very good service. Same shop iirc.

The picture was the X9 SILVER, but the advert was for a X9L silver which is what arrived. I was hoping for the same as previous though / not the lighter one.  (this is not the issue).

 

The issue - After fitting the new chain something in the mechanism skips every now and again when under heavy load ie uphill. SLX Hollowtech II.

I purchased a new OEM middle ring @ £20 from Wiggle thinking this may be the cause as it is the original one, and fitted this along with the new chain. Same issue remains.

I cleaned and lubed the new chain just in case this was the cause, but still the issue.

 

It is as if the mechanism is trying to move up / down gears without input from the shifter.  I have adjusted the shifter and reset it. Moves up and down properly without dragging either side.

I have now put both old components back on the bike to see if symptom persists as it did not do this with this set up iirc. The chain is just a bit stretched.

The rear cassette has been replaced before and i do not think this is the issue. I would have to put a camera on it to record what is happening, but i do not have one, Lol.

 

Trying to eliminate possible causes..................Any thoughts?

 

[moonwrasse]

New cassette is the answer. Also check the chain does not have any stiff links. 

  If changing a middle ring and new chain the cassette should be changed too. 

[KenONeill]

@Tilt - Start by examining the sprockets (both ends) that you use most for any evidence of the teeth hooking (looks exactly like it sounds). Given that you admit to having stretched the old chain, I'm almost certain there's some hooking someplace.

[Tilt]

Cheers guys. Chains do stretch a little over time, especially if you ride hard, and i have done some hard riding.............You can get a tool to measure chain stretch, if your that sort of person.

Thinking about it, the reason for the new chain was more that the twist in it was excessive, so getting loose. Only noticed a little stretch after putting alongside the new one.

Also the cassette has been renewed before, so not that old. And they are expensive, or the one i would want is.

 

I've yet to ride using the old kit yet, so to eliminate any other issues on the bike / wheel or crank.

Edited 30 August, 2017 by Tilt

[penguin17]

Chains don't stretch; neither do gear and brake cables.  

 

 

[Ootohere]

LOL, they just elongate.   Or is it all a myth as some say?

[Tilt]

On 8/29/2017 at 15:09, moonwrasse said:

New cassette is the answer. Also check the chain does not have any stiff links. 

  If changing a middle ring and new chain the cassette should be changed too. 

 

I didn't want to jump to this conclusion, but this may be the only thing left, but at around £45/50 they are not cheap. As mentioned already replaced once before.

The weird thing is that on both the big ring and the granny ring there are no issues with the new chain / rear cassette. It works fine.

The new middle ring looks hardly any different to the old one. My old chain is 4mm longer than the new one, stretched / elongated or whatever you want to call it, but chain stretch is the term used in this instance as far as i am aware.

 

The only other possibility is a faulty KMC X9L Silver, purchased from Merlin Cycles, which is doubtful at a guess.

[Ootohere]

Really,

4 mm for a like for like chain with the same size links and the same number?  

That is some impressive stretch / elongation.

[KenONeill]

On 9/25/2017 at 14:23, penguin17 said:

Chains don't stretch;  

 

 

For certain meanings of "stretch" that is. We're not suggesting that the individual plates that make up the links get longer: rather we're using the term to mean that the link pins and/or the holes in the side plates get longer.

 

There used to be photographs in "Richard's Bicycle Book" showing 2 chains (one brand new, the other 2_000 miles old) with the same number of links. The old one was 6mm longer than the brand new one hanging under gravity, but lying on a table could be "compressed" to the same length.

[Ootohere]

& now especially with x1 and SRAM Eagle 12 rear set ups, chains are probably the most important they have been on bikes, 

and the difference in price between hollow pin or solid pin and the links finish is unbelievable to some.

 

 

Edited 26 September, 2017 by Headinawayoffski

[penguin17]

44 minutes ago, Headinawayoffski said:

& now especially with x1 and SRAM Eagle 12 rear set ups, chains are probably the most important they have been on bikes, 

and the difference in price between hollow pin or solid pin and the links finish is unbelievable to some.

 

 

Must be a very finite to set up the Eagle 12.  I had enough issues getting Apex 1x11 to work on my CAADX when I stuck a 42T cassette on. 

[Ootohere]

Dead simple be it the £900 drivetrain set up or the £450, & as long as they have the Eagle mark they are compatible when upgrading parts on the drivetrain.

Crazy prices though on the weight saving components.

Edited 26 September, 2017 by Headinawayoffski

[Tilt]

22 hours ago, Headinawayoffski said:

Really,

4 mm for a like for like chain with the same size links and the same number?  

That is some impressive stretch / elongation.

 

Really, yes bud, 4mm.

 

22 hours ago, KenONeill said:

There used to be photographs in "Richard's Bicycle Book" showing 2 chains (one brand new, the other 2_000 miles old) with the same number of links. The old one was 6mm longer than the brand new one

 

Cheers Ken. Saves me photographing mine to prove a point. 

[Tilt]

On 9/25/2017 at 14:23, penguin17 said:

Chains don't stretch; neither do gear and brake cables.  

 

What about stretch bolts? Do they stretch? 

[penguin17]

The chains themselves don't 'stretch' they have zero elasticity, they elongate.   The link pins wear inside the bushing allowing for sideways movement.  THEY DO NOT STRETCH

[Ootohere]

A commonly used term when something becomes longer even if used wrongly as per the dictionary.

 

Before there was on sale Pre-Stretched Gear & Brake Cables many used to try stretching them, and even since Pre-Stretched are the common sort sold, 

they still elongate over time, or some do, because obviously there are many types / makes from Sh!te ones to not so Sh!te, to wundeba.

[KenONeill]

2 hours ago, penguin17 said:

The chains themselves don't 'stretch' they have zero elasticity, they elongate.   The link pins wear inside the bushing allowing for sideways movement.  THEY DO NOT STRETCH

OK, so every other materials scientist in the history of the science, including the ones who taught me, are wrong because you say so! Alternatively, read https://en.wikipedia.org/wiki/Elasticity_(physics) and then admit you're wrong.

[penguin17]

59 minutes ago, KenONeill said:

OK, so every other materials scientist in the history of the science, including the ones who taught me, are wrong because you say so! Alternatively, read https://en.wikipedia.org/wiki/Elasticity_(physics) and then admit you're wrong.

Ok, I'll admit it...chains don't stretch, even using bold text doesn't change that.  There's an illusion of stretch due to the way they wear but the plates themselves will be exactly the same length whether or not the chain is at 0.50, 0.75 or 1% wear rate.  

 

 

[Tilt]

On 9/27/2017 at 13:35, penguin17 said:

The chains themselves don't 'stretch' they have zero elasticity, they elongate.   The link pins wear inside the bushing allowing for sideways movement.  THEY DO NOT STRETCH

 

On 9/27/2017 at 13:07, Tilt said:

 

What about stretch bolts? Do they stretch? 

 

Just asking...............

Edited 28 September, 2017 by Tilt

[Tilt]

Ended up having to purchase the XT M770 as the SLX doesn't seem to be available anymore.

 

Fitted the new cassette along with the (almost new) KMC X9L Silver chain, and the new front middle ring.

 

It is better, but still has the occasional stutter., but with the other set up SLX cassette and X9 Silver chain (not light) it has always been super smooth.

 

I can only assume it is the chain and would not recommend the X9L. However, I would recommend the KMC X9 Silver, (solid links) if you can find one.

[hwr1983]

Had you reset the indexing on the deraillieur (high/low limit screws etc) as using the "stretched" (or should I say "out of shape") chain would need different adjustment than a brand new one?  I would presume you have done this but worth asking

[Tilt]

20 hours ago, hwr1983 said:

Had you reset the indexing on the deraillieur (high/low limit screws etc) as using the "stretched" (or should I say "out of shape") chain would need different adjustment than a brand new one?  I would presume you have done this but worth asking

 

The only difference that makes is how far the swing spring stretches on the lower derailleur arm, forwards or backwards, and that would be such a tiny amount and irrelevant anyway.

 

Makes no difference as regards indexing / sideways movements, as you suggest. Sorry.

[Jackie-Lancs]

As a former bike mechanic chains do not stretch. Pins wear. rollers wear and so the distance between links become greater. Never have had a poor kmc chain so suspect the old worn chain had rapidly worn the cassette. If outer & inner chain rings are ok then suggest pilot error in gear use - the fact that all gears can be selected doesn't mean that using them all is ideal. Sounds like you use middle ring regardless.

[Tilt]

^^^ you're right mate. I have no idea what gear to use for going uphill or if i should change when going downhill.

 

I just flick the levers and hope for the best, Lol. 

[KenONeill]

@Jackie-Lancs - So, if you hang up a brand new chain next to one that's done 3 or 4 years, are they the same overall length or not? No-one has claimed that the individual fishplates change length measurably, only that the overall length of the chain does!