Page 1 of 2

New chain woes

Posted: 24 Jan 2017, 1:50pm
by Annoying Twit
What would cause a new chain to shift badly including the chain sometimes getting caught in both front and rear derailleur during shfits?

Re: New chain woes

Posted: 24 Jan 2017, 1:54pm
by barrym
What's the condition of the chain wheel and sprockets? A new chain on old sprockets can often be worse than the old chain was.

Re: New chain woes

Posted: 24 Jan 2017, 2:02pm
by Annoying Twit
barrym wrote:What's the condition of the chain wheel and sprockets? A new chain on old sprockets can often be worse than the old chain was.


They don't look too bad. Fairly newish.

Re: New chain woes

Posted: 24 Jan 2017, 3:16pm
by Threevok
Are you sure it's the correct chain ?

Re: New chain woes

Posted: 24 Jan 2017, 8:23pm
by Annoying Twit
Threevok wrote:Are you sure it's the correct chain ?


It's a KMC Z8 chain being used on a Carrera Subway 1 (7 speed). It should be right. It feels fairly clunky, but KMC chains often seem to feel a bit clunky.

I was originally going to buy a Z7, but the shop talked me into buying the Z8. I'm not sure what I think about this right now. But, the packaging does say that the chain is suitable for 21 speed bikes.

Re: New chain woes

Posted: 24 Jan 2017, 8:44pm
by Threevok
Annoying Twit wrote:
Threevok wrote:Are you sure it's the correct chain ?


It's a KMC Z8 chain being used on a Carrera Subway 1 (7 speed). It should be right. It feels fairly clunky, but KMC chains often seem to feel a bit clunky.

I was originally going to buy a Z7, but the shop talked me into buying the Z8. I'm not sure what I think about this right now. But, the packaging does say that the chain is suitable for 21 speed bikes.


Should be OK, as a Z8 is a 7-8 speed chain. However, what did you have on there before ?

I found switching from Shimano to KMC problematical, when the Cassette has was "worn in" using the Shimano chain. In the end, I gave up and went back to the same Shimano HG chain.

Not that I am dissing KMC though. I have one on my Single speed and am very happy with it.

Re: New chain woes

Posted: 24 Jan 2017, 8:50pm
by NATURAL ANKLING
Hi,
Had a problem recently and only sure fire way is substitution of parts till it works.
My problem came after 0.75% chain stretch which would normally be ok on any other junk chain I use (7S) the chain side plates are very flat not shaped at all, yet to swap the chain.

Re: New chain woes

Posted: 24 Jan 2017, 9:13pm
by Annoying Twit
Thanks all.

The previous chain on there appears to be a KMC given the small Zs I can see on the links. However, it was already on the bike when it was bought second hand.

At present I have the old chain back on with a link to reattach it. It may have two links on it now given that it appears to be a KMC.

I have KMC on my single speed. I had a KMC chain on a previous bike I had, but when I put that chain on I also changed the rear derailleur and freewheel. I've got a KMC Z7 in my parts bin at the moment, so I could try that.

Re: New chain woes

Posted: 24 Jan 2017, 9:28pm
by Brucey
new chain + old sprockets = problems .... if the old chain was a bit worn.

If the old chain was less than 0.5% worn then a replacement chain ought to run OK on those sprockets. However if the old chain was more worn than that you can expect the new chain to skip on the worn sprockets, and the chainrings may do weird things too.

The usual thing is to change the cassette/freewheel when you fit a new chain. If you do this often enough the chainrings will last several chains, but if you don't, they won't.

cheers

Re: New chain woes

Posted: 24 Jan 2017, 9:29pm
by Threevok
A Z7 has a Pin Length: 7.3 mm
A Z8 has a Pin Length: 7.1 mm

That may have something to do with it too

Re: New chain woes

Posted: 24 Jan 2017, 9:32pm
by NATURAL ANKLING
Hi,
The cheapest KMC chains have just KMC on the plates, I demolished one in 330 miles , it snapped :o

I find it a good idea to have a cheap chain checker to hand which gives a rough guide to the chain stretch which takes a few seconds but you don't need your glasses either, I know I know I know! that this is not always conclusive but I use it as a comparator, and on 7S set up like mine above 1.0% stretch and shifting goes a bit vague, you can buy them for a few quid.

I have probably had about a dozen used chains on my skip trainers even seized rusty ones which I have revitalized, the one I mentioned above was the only one that gave me trouble at 0.75% stretch.

Re: New chain woes

Posted: 24 Jan 2017, 9:49pm
by Annoying Twit
Threevok wrote:A Z7 has a Pin Length: 7.3 mm
A Z8 has a Pin Length: 7.1 mm

That may have something to do with it too


I'm tempted to put the new Z7 chain on the bike. If that works, then it indicates that the Z8 is the wrong size. Since a shop talked me into a Z8 instead of a Z7, saying it would fit, I would feel justified in a return if it's the chain that doesn't fit.

Are inexpensive chain wear checkers a reasonable choice: http://www.ebay.co.uk/itm/Chain-Checker ... SwIgNXrYR9 Or would it be 'buy cheap, pay twice'? EDIT: Natural Anking does say 'cheap chain checker'.

Re: New chain woes

Posted: 24 Jan 2017, 9:53pm
by Threevok
Annoying Twit wrote:Are inexpensive chain wear checkers a reasonable choice: http://www.ebay.co.uk/itm/Chain-Checker ... SwIgNXrYR9 Or would it be 'buy cheap, pay twice'? EDIT: Natural Anking does say 'cheap chain checker'.


That looks identical to the one I bought from CRC. Paid more than that though :evil:

Re: New chain woes

Posted: 24 Jan 2017, 9:55pm
by Annoying Twit
Threevok wrote:That looks identical to the one I bought from CRC. Paid more than that though :evil:


Thanks. Purchased.

Re: New chain woes

Posted: 25 Jan 2017, 12:26am
by NATURAL ANKLING
Hi,
Like I said use it as a comparator, you will get to know when you need a new chain.

I run mine out to 1% on my skip bikes which use recycled chains, after this the chain gets noisy and chain suck is common.

I don't change the rear cassette till it on its own starts to cause problems like skipping in high gears because the sprockets are really shagged, and hooking of the teeth.
The sunday tourer gets cassette changes earlier :)
I suspect that some of the bottom end KMC chains (not the ones you mention) might be bellow the quality of an HG50 shimano?

After a while you get a feeling with the chains you use and I am a glutton for sticking with what I know, like using the same engine oil for over 25 years, that's same type not same oil :)
Hmmm one of my cars has been with me for twenty years now :?