Would I need to buy two chains to fit on a 11-40 & 30/46 , 440 mm chainstay?
 

On most of the chains it says 116 links, but I am not sure if I may need a bit more, but I cannot find any chains that are longer than 116 link. For anyone running a 11 - 40 cassette & 46/30 chainset, how many links you think is enough? Will I be short a few links if I get one chain and need another chain to extend it? Any longer chains if that is the case?

It depends on chainstay length. Just try it out.

Had to slightly shorten a 116 with 11-40 and 40-30-20 and 425mm with the wheel back 15mm in the drop outs. Reckon a 116 will do it.

Ok, one might be able to estimate it, more or less.

440mm ==> 17.32" x 2 = 34.64"

Your chain wraps around pretty close to the tangents on the sprockets (when stretched out, and some kind of a shadow derailleur). So, 40T ==> 20T or 10" to wrap halfway around.

46 ==> 23T, or 11.5" for half.

So...

34.64 + 10 + 11.5 = 56.15" (about).

Double that, and you'll need about 112.5 links. Rounding up one gets 113 single links, or 114 in pairs.

You may be able to get away with 114 links, and 116 links should be plenty.

Assuming my calculations were close enough. :foo:

Assumptions and calculations are fine but verify using the actual hardware! When you assume...

Whatever you do make absolutely certain that the chain is long enough to shift into the 46 front/40 rear without strain; test this by turning the crank by hand slowly and STOP if the chain gets tight, and add a link pair. Or go a little long, the worst that will happen is a slack chain when in 30/11, which you should avoid anyway.

I tend to agree. A Niner RLT 9 RDO with 430 mm chainstay, 46/30 crankset and 11-42 cassette uses all links on a 116 link chain.

I also agree with [MENTION=205349]dsbrantjr[/MENTION]'s recommendation to go long on the chain and shorten if needed.


-Tim-