Rear derailleur capacity & chain length

itboffin
itboffin Posts: 20,064
edited March 2009 in The workshop
I currently have a Shimano 105 SS rear dérailleur on my CX bike running with a 11-30T cassette and compact 50/34T up front, indexing is good, shifting seems fine BUT I am unable to shift above 20-23T when running on the big ring which I think is a chain length issue as the dérailleur freezes.

Questions;

1. Is it safe to mix two 10 speed chains, different brands KMC & Shimano
2. The capacity of the 105 rear dérailleur
# Max rear sprocket 27T
# Max capacity 29T

By my calcs i'm currently 35T Max, I know manufacturers run conservative on their estimates but am I pushing it too far?

I could avoid 50T / 30T combo of course :D
Rule #5 // Harden The Feck Up.
Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.
Rule #12 // The correct number of bikes to own is n+1.
Rule #42 // A bike race shall never be preceded with a swim and/or followed by a run.

Comments

  • ride_whenever
    ride_whenever Posts: 13,279
    did you fit the chain to the correct length when you fitted your outsize :shock: cassette?
    Neeermad
    Carbon 456
    456 lefty
    Pompino
    White Inbred
  • itboffin
    itboffin Posts: 20,064
    ride_whenever wrote:
    did you fit the chain to the correct length when you fitted your outsize :shock: cassette?

    I have now :wink:

    The Shimano 105 chain that came with my Trek has been extended by 1.5 KMC links damn KMC chains are easy to break/fix I can now shift 26/50t easy and 30/50t with a little effort, I might give that one a miss :?

    So apart from bar tape and a rear brake cable my CX project is finished, it rides beautifully the 9 speed champy shifters running perfectly with the shimano drive 10 / 8 speed drive mix and a good range of gears.

    for now it's staying on road until I get used to the campy shifters and canti brakes :shock: not quite the same stopping power and calipers but pretty good nevertheless.

    We shall see what happens when I start attacking the hills and bouncing off road. :D
    Rule #5 // Harden The Feck Up.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.
    Rule #12 // The correct number of bikes to own is n+1.
    Rule #42 // A bike race shall never be preceded with a swim and/or followed by a run.

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