Would you bother resizing chain from 27 to 28?

galego
galego Posts: 15
in Road buying advice
Hi
Looking for a bit of advise.
I am going to fit a 12-27 cassette and new chain. I will size the chain big ring to biggest sprocket (27).

Two questions now:

1- If i was then to fit a 11-28, would i need to size the chain?

2- If i was to fit a 11-30 for a few days, would it be ok to leave the exisiting chain cut to 11-27?

Thanks in advance for the advice on the above two points.

Comments

  • bondurant
    bondurant Posts: 858
    I think the former would be fine. For the second scenario, the obvious way to check would be to try it. Big-big would potentially be the issue, but if you made an effort not to use e.g. your 2-3 biggest sprockets you'd probably be OK.
  • galego
    galego Posts: 15
    bondurant said:

    I think the former would be fine. For the second scenario, the obvious way to check would be to try it. Big-big would potentially be the issue, but if you made an effort not to use e.g. your 2-3 biggest sprockets you'd probably be OK.

    If using the former chain with the 30 sprocket, would it be alright in the small ring and when in the big ring avoid usimh the 2-3 biggest sprockets?
  • pblakeney
    pblakeney Posts: 27,159
    bondurant said:

    I think the former would be fine. For the second scenario, the obvious way to check would be to try it. Big-big would potentially be the issue, but if you made an effort not to use e.g. your 2-3 biggest sprockets you'd probably be OK.

    I tried that when I went from an 11-25 to a 12-29.
    I forgot. It didn’t end well. :s
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • bondurant
    bondurant Posts: 858
    galego said:

    bondurant said:

    I think the former would be fine. For the second scenario, the obvious way to check would be to try it. Big-big would potentially be the issue, but if you made an effort not to use e.g. your 2-3 biggest sprockets you'd probably be OK.

    If using the former chain with the 30 sprocket, would it be alright in the small ring and when in the big ring avoid usimh the 2-3 biggest sprockets?
    The small ring would be fine because the chain would be shorter than ideal. It's where the chain's capacity is used at its fullest you will have the issue i.e. in big big. The derailleur may be extended beyond where it is meant to and this means the chain will run roughly and you may tear off the mech entirely.

    Note how straight the chain is and how close the mech is to the largest sprocket:


  • lakesluddite
    lakesluddite Posts: 1,337
    If you're just using the 30 tooth for a few days, why not just get another chain with powerlinks - use it for those few days, then swap back and save the new chain for when you need to replace your old one. I'm presuming as well that your current rear mech can take a 30 tooth cassette - ie it's not a short cage RD?
  • galego
    galego Posts: 15
    It is a short cage but was thinking it could take 30 tooth.

    I might just fit a 11-28 cassette and leave it that way.
  • thecycleclinic
    thecycleclinic Posts: 395
    edited February 2020
    The chain wrap changes by 1/4" moving from a 27t to 28t final sprocket therefore the chain cant be resized to accommodate this.

    Each tooth added add 1/4" of chain length required.
    www.thecycleclinic.co.uk

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