Chain replacement

[Oggi]

My chain has reached .75 wear on my Park tool gauge after 2600miles. I looked at SJS and the KMC X1 is out of stock so I called in my LBS and they had one. £7 more than SJS but they offered to fit it so good deal I thought.
They struggled for 2 hours and could not get the new chain to fit. It is the same number of links as the old chain, and the same chain. But it is either too tight on the minimum adjustment or so slack it falls off if we put an extra link in. Eventually they put the old chain back on and agreed to do some research and get me back in when they have found out what is going wrong.
Does anyone here have any advice I can use. Thanks in advance
Doug

[Oggi]

Sorry clicked the wrong button before I finished. The bike is my Thorn Mercury with the lightweight eccentric bottom bracket.
Doug

[Matt2matt2002]

Sorry clicked the wrong button before I finished. The bike is my Thorn Mercury with the lightweight eccentric bottom bracket.
Doug

Half link the answer?

[Oggi]

How does a half link work?

[Matt2matt2002]

How does a half link work?

Sorry. Not sure but I've heard other folks here mention it. I'm sure someone will enlighten us soon.

[lewis noble]

I think it's a shorter link . . . . . NOT just one side of the link . . . . .

[PH]

Putting the old one back was the right thing to do, .75 is OK for a derailleur, but if you're going for that on am IHG then use cheap ones!  2,600 miles!!! I begrudge the cost if it doesn't last 10,000. Even at .75 the sprocket is unlikely to play nicely with a new chain.  I don't measure my chain, I change it either when I run out of adjustment or the sprocket looks worn.  A decent quality chain will last the side of a sprocket. 
I really don't know what your bike shop is doing, it's a standard chain on standard size components, if an old chain fitted a new one will.  Or have you changed something else as well?  The Mercury has some recommended sprocket/chainring combinations required to take advantage of the smaller EBB (Now changed on the MKIII)

[Oggi]

Thanks for all the advice folks. It sounds like I’m worrying unnecessarily. The sprockets are fine and I’m only at 50% of the available adjustment. My LBS have been very good with my derailleur bikes but they admit that the IHG is a new beast to them. They are used with single speed so not too unfamiliar. I’m inclined to leave it a while and change when I run out of adjustment. I have tried SJS but they are obviously running on skeleton staff.
The sprocket and chain ring are a standard combination of 47 x 17 and I have not changed anything other than the chain.
Thanks again folks.

Doug

[B cereus]

As PH says the early Mercury frames had a mini eccentric BB which only allows for a little more than a half a link of adjustment. For this reason certain combinations of chainwheel and sprocket are only possible by using a half link.
 
Has your old chain got a half link in it?

There's a list of recommended chainwheel  sprocket combinations for the mini eccentric BB in the mega brochure.

Normally its only possible to increase or decrease the length of a chain by one whole link. The half link does what it says on the tin and allows increasing or decreasing the length  by half a link.

[PH]

I’m inclined to leave it a while and change when I run out of adjustment.

That sounds like the best plan.  It's what I tend to do, have done the same with an EBB with full adjustment so doing it with the Mercury still isn't getting close to maximising usage.  I keep meaning to remove a link then add a half link once I've reached the end of the adjustment, that would take it back to the start.  But when it comes to it I can't be bothered, a new chain and half life of a chainring and sprocket still comes to under £40, so still reasonable value and you always know there's plenty of life in what you're using.  I have a couple of times moved the used chain over to my Alfine around town bike, where I've got another few thousand miles use.

[UKTony]

Hi all
Apologies if I’m repeating what others have already mentioned but the KMC X1 chain is not just out of stock it’s been superseded by the KMC E1, SJSC part number 53243. I waited and waited for the restocking email and after a few weeks heard nothing so rang Thorns. Apparently it’s essentially the same chain and the KMC X1 missing link is compatible with the successor e1 chain so don’t throw away all your spare X1 missing links!
Regards
Tony

[RobertW]

Very much the same question as the OP.  On my 18 month old Mercury II, I have reached about 5500 miles on the KMC e1 chain originally fitted.  Using a Rohloff chain gauge I am approaching 0.075mm wear; there is no significant wear to the teeth on the chain ring or sprocket.  I am running 45x19 which is one of the recommended combinations; when new the mini EBB had about 3/4 of the total adjustment available.  I have taken up the slack once but still have just over half the adjustment still available.

The question is, do I replace the chain now or continue until all the adjustment is used up ?

Current prices on SJS are for a KMC e1 £26.99, sprocket £17.99, double sided chainring £49.99.  Which I think makes replacing the chain unattractive in the short term.

Based on a comment up thread a new chain may not run smoothly with the 'little' wear I have.  Which makes me minded to continue with the current chain.  If the rate of wear does not increase I would hope to get another 5000+ miles before the adjustment in the EBB is taken up.  After that I guess an option is to fit a half-link and run until the sprocket and chainring are really worn.

Any thoughts
Thanks
Robert

[PH]

The question is, do I replace the chain now or continue until all the adjustment is used up ?

The mini EBB does make it a little more complicated.  You're not getting the full value of an expensive chain.  When you get to the end of the adjustment, you could remove a link add a half and start again:
https://www.sjscycles.co.uk/chains/kmc-12x332-z510l-12-link-offset-half-connecting-link/

Current prices on SJS are for a KMC e1 £26.99, sprocket £17.99, double sided chainring £49.99.

Don't forget each cycle only costs 50% of the reversible sprocket and chainring.  It might also be that the rate of chain wear slows, I'm sure some of the early elongation is settling in rather than wear.

The chain on my Mercury slipped a couple of times on a long ride last week, it still looks OK and I haven't been able to make it slip again on a couple of local rides, I'll monitor it, I have a new chain ready to go on. 23,700km, I'd like to round that up!

[mickeg]

On derailleur bikes, I swap chains at 0.75 percent elongation. But on IGH bikes, I wait until over a percent.

You said you used a Park gauge.  The cheap gauges that only contact the chain at two spots are not very accurate, the gauges that have three hooks of the gauge are much better.

Park, Pedros, maybe by now others make the good ones, described here how to use:
https://www.youtube.com/watch?v=iOaFF_4CqJg

In the video, note at 0:57 that they use their fingers to put tension on the chain between two hooks, that is a key to this chain checker being more accurate.

Thoughts on that from Zinn:
https://velo.outsideonline.com/road/road-racing/measuring-chain-wear-accurately/

I use the Pedros one Zinn cites.

[mickeg]

I think it's a shorter link . . . . . NOT just one side of the link . . . . .

All links are a half inch.

The half link allows you to use an odd number of links instead of an even number.  Looks like this.
https://www.amazon.com/KMC-Z410-OL-Half-Link-8-Inch/dp/B001CNC2UU/