Extending chain by one link?

[youngoldbloke]

About to install a new cassette with 30T bottom, existing 28T. Machinehead Chain length calculator recommends 55 links, current chain 54, SRAM, joined with quick link. Any reason why I shouldn't add another complete link comprising another (KMC) quick link, (outer plates) and the inner from the spare part of the (almost new) original chain?

 

[alicat]

If you're going to add the inner from the original chain why not add the outer as well?

 

[Carbon]

Hi, You'll probably find the un-rounded calculation for the chain length is only 0.5 of a link difference between 28 and 30T but the calc rounds up so gives you a full link. I would suggest stick with your existing 54 link length, it will be fine. Just stick your chain on the 30T and largest ring up front (not even a combination you should run) and so long as you still get a slight S shape with the chain through the jockey wheels you'll be fine. (Maybe a slight adjustment of the B screw on the rear derailleur to accommodate the larger cassette). Sorry if I'm teaching you to suck eggs !!!!

 

[youngoldbloke]

If you're going to add the inner from the original chain why not add the outer as well?

I wanted to avoid riveting the chain. I know many do, but it is not recommended for thinner chains (9 and esp.10 speed).
I think I'll try Carbon's approach first anyway, as the unrounded figures are 53.685 for 28T, and 54.15 for 30T.
Thanks both.

 

[andrew_s]

About to install a new cassette with 30T bottom, existing 28T. Machinehead Chain length calculator recommends 55 links, current chain 54, SRAM, joined with quick link. Any reason why I shouldn't add another complete link comprising another (KMC) quick link, (outer plates) and the inner from the spare part of the (almost new) original chain?

There's no reason why you shouldn't use several quick links in one chain, but I'd check whether you can change into the 30T sprocket when on the big chainring first. If you can, there's no reason to extend the chain.

 

[simmi]

I would try it without the extra link first, I did something similar and presumed I would need a longer chain but found that the chain was too long on the smallest cog (11T) I have also always been told you should change you chain if you change you cassette, good practice and all that.

 

[youngoldbloke]

I would try it without the extra link first, I did something similar and presumed I would need a longer chain but found that the chain was too long on the smallest cog (11T) I have also always been told you should change you chain if you change you cassette, good practice and all that.

As Carbon suspected, having looked at the unrounded figures there is probably no need anyway. I'm a great believer in 'try it and see'. I don't see any need to change the chain - the existing cassette has only done a few hundred miles, and the chain is even newer. Will report back.

 

[youngoldbloke]

So far so good ..... Just fitted the 11-30 cassette. Seems fine, even on 50x30 (and this with a short cage* Tiagra mech).
[* 55mm jockey wheel centres]

 

[HLaB]

After ripping off a rear deraileur personally I would lengthen the chain. I recently upped my cassette from a 11-26 to a 11-28 and Sheldons method (big ring/ big cassette, no deraileur and one link overlap suggested 55 for me and a few sites also said 55 but the unrounded was 44.2 so I probably would have got away with 44links.