I’ve cut my KMC chain too short (Numpty)

dazzawazza

I’m upgrading my Allez and in a finishing off frenzy of my I’ve managed to cut my KMC chain too short so that the derailleur pulleys are less than 90 degrees when on large chainring / small sprocket combo (about 1 to 2 links too short). The set-up is a 9-speed double 53/39 chainset and 12/27 cassette with short cage derailleur. As far as I can see I’ve got three options:

1) Add links back using chain tool (will this create a weak link in the chain?).
2) Buy another KMC removable link and have two on the chain joined together (I’m almost certain this will create a weak link in the chain?)
3) Leave the chain as it is and remember to never shift onto big / big combination. Replace after 800 miles.

What should I do? :shock:

redddraggon

dazzawazza wrote:

2) Buy another KMC removable link and have two on the chain joined together (I’m almost certain this will create a weak link in the chain?)

There's no reason doing this will make a weak link in the chain - no problem doing this as far as I'm concerned.

campagsarge

If you do option 2 dazzawazza can you let me know how you get on as I have a similar dilemma.

Cheers.

andrewgturnbull

Go for option 3 Don't worry too much about it, it's no big deal.

Cheers, Andy

The Mechanic

Rejoining the chain with the chain tool should not cause a weakness. This is how it was done for all chains until rellatively recently.

Neither should the use of another joining link make it weaker.

Before you do any of these, first check if you have sufficient chain by running right through the gears, particularly big/big combination. You might just be lucky.

topdude

As you have a normal 39 / 53 chainset it will probably make no difference.
With the bike on a stand or upside down try changing gear from small / small to big / big and watch the mech cage. See if it copes with the chain slack from one extreme to the other. Don't worry about the 90 degree thing it's just a guide.
If it is too tight on the big / big combination just leave it as you will never use it anyway.

dazzawazza

Thanks for the advice.
The big/big combination seems to have enough slack without the guide pulley and rear cog touching so I'm not going to worry about it. I won't ever use that combination on purpose anyway.

Pirahna

Just a thought. Using another joining link won't lengthen the chain as you'll need to remove a link to fit it.

andy_wrx

Pirahna wrote:

Just a thought. Using another joining link won't lengthen the chain as you'll need to remove a link to fit it.

Not if you use it to join-back some of that which was removed.

I'd not want two joining links right next to one another though. If - say - it's two links short and you cut 10 links off as excess, I'd break 8 links off the end and join the 10 back on, so the joining links were 10 apart.

dazzawazza

The joining links are brilliant though. I already had to break the link when I discovered I hadn’t threaded the chain through the derailleur correctly. Told you I was a numpty at this; actually I think it’s all down to being in a hurry to get the bike back on the road. It’s been a month of riding my MTB as I was doing the upgrade when I had time.
I’ve been for a short test ride and everything is working well now. After being used to Sora I was still trying to use my thumbs, but I’ll get used to it.
All I have to do now is sand down and paint the scratched second hand shifter caps (shifter cost me £20) and install the new bar tape.

redddraggon

dazzawazza wrote:

I already had to break the link when I discovered I hadn’t threaded the chain through the derailleur correctly.

I don't know how many times I've put chains on bikes now, but I've done that every time - so I'm really glad of the missing links.

dazzawazza

redddraggon wrote:

so I'm really glad of the missing links.

Hi redddragon, do you have a team of apemen that help you with chain installation?