Chain Length Calculater

As each year passes the hills get a little harder so I am looking at changing my 11-30 to a 11-34. I have the large cage so hopefully shouldn't be a problem.

Is there a rule of thumb as to how many more links should the chain be longer in relation to upsizing the cassette or is it just something one gets to know after years of doing it.

Thanks in advance for any input.
 

robgul

Guru
Various methods but I use this - wrap chain round largest sprocket and largest chainring (NOT thorugh the rear mech) and overlap 2 links - cut to size. If in doubt err one link bigger as it's way easier to cut a link off than pin one back (and use a "magic link" - which will be supplied with most chains .... even Shimano now have some with magics)

Rob
 
If your chain length is OK at present, and you're swapping to a large sprocket with 4 more teeth, then you should be OK with 2 more links in your chain.
 

Ajax Bay

Veteran
Location
East Devon
If your chain length is OK at present, and you're swapping to a large sprocket with 4 more teeth, then you should be OK with 2 more links in your chain.
With a large spocket 4 teeth more, only 2 of those extra teeth will need to be engaged (at a point in time) so, if your chain length is OK at present, one more one inch link will be right.[/QUOTE]
 

Sharky

Guru
Location
Kent
Try with the old chain before you cut the new one.
 
With a large spocket 4 teeth more, only 2 of those extra teeth will need to be engaged (at a point in time) so, if your chain length is OK at present, one more one inch link will be right.
Yes, that's what I meant. My links, like KMC's, are only half-an-inch. :smile:

original-bicycle-chain-kmc-x8-x8pl-8-speed-chain-116-links-ultralight-bicycle-chain.jpg
 
Last edited:
Thanks for all your replies, I will give it a go.

So following on then when I have fitted the new cassette with it being bigger will I have to re index the gears (something I have no patience for) or should they just work?
 

Vantage

Carbon fibre... LMAO!!!
My method, which has never once caused any issues, is to take it out of the packaging...and wait for it...

Fit it!

No messing about measuring links to the last mm or wrapping it around certain sprockets and chainrings.
Your average chain comes supplied as 114 or 116 links. It'll work perfectly fine as is.
 

robgul

Guru
My method, which has never once caused any issues, is to take it out of the packaging...and wait for it...

Fit it!

No messing about measuring links to the last mm or wrapping it around certain sprockets and chainrings.
Your average chain comes supplied as 114 or 116 links. It'll work perfectly fine as is.
Hmm, quite a few now come with a 118 link option which I would suggest could cause you problems - at the shop I find that, from a 114 chain, it's an average of 2 links (i.e. 4 rollers) to cut off. You really do need to get the correct length for efficient traction and shifting.

AND - at the shop : I have a superb home-made tool for use when you have an existing chain .... it's a long thin piece of timber about 3" wide and longer than 118 chain links that has 2 battens screwed along the long edges to form a "channel) - at one end of the channel there are 2 nails side by side. Connect old and new chains on a nail each, compare at the other end and cut. Simples and saves load of time - and no oily mess on the bech from the old chain. The "tool" hangs on the wall.

Rob
 
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