Ease of swapping cages on rear 105 5800 derailleurs ?

andylav
andylav Posts: 308
edited October 2017 in Workshop
Can anyone offer any advice on how easy it is to swap the cages over on two 105 5800 rear mechs.

Wanting to swap short and medium cages across mechs and, without removing chains and mechs for a closer look, would like to know if it's something a reasonably competent home mechanic could attempt without special tools.

Thanks in anticipation for any advice and / or helpful hints or tips

Comments

  • boblo
    boblo Posts: 360
    Very. It's a 5 min job. There's a little grub screw on the knuckle, loosen that off and slide the cage off the spigot. On the replacement cage undo one side of the lower jockey to get the chain in the cage then slide the cage onto the spigot, replace the grub screw. Pop the chain in and do up the jockey retainer and you're done. Takes longer to type than to do.
  • andylav
    andylav Posts: 308
    Boblo - thank you, very much what I wanted to hear !
  • svetty
    svetty Posts: 1,904
    Bear in mind that cage length isn't the only difference between the the GS and SS models of the mech. The geometry of the parallelogram and hence the way the mech 'tracks' the cassette is different as well to accommodate the larger jumps between sprocket diameters. It shouldn't make a large difference in practice mind you....
    FFS! Harden up and grow a pair :D
  • andylav
    andylav Posts: 308
    Thanks Svetty - something to pay attention to when trying the first few shifts after swap over.

    If it proves to be an issue, will swap back and keep the status quo.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    andylav wrote:
    Thanks Svetty - something to pay attention to when trying the first few shifts after swap over.

    If it proves to be an issue, will swap back and keep the status quo.

    Or just change the mechs over - it's only a ten minute job including indexing.

    Or am I missing something?
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • boblo
    boblo Posts: 360
    Svetty wrote:
    Bear in mind that cage length isn't the only difference between the the GS and SS models of the mech. The geometry of the parallelogram and hence the way the mech 'tracks' the cassette is different as well to accommodate the larger jumps between sprocket diameters. It shouldn't make a large difference in practice mind you....

    I'm not certain that's the case. I've both mechs and the top parts look identical.
  • andylav
    andylav Posts: 308
    Thanks for the replies gents - much appreciated.

    The main reason that I want to switch the cages instead of just swapping mechs over is for aesthetics - there's more to it than just that but I didn't want to bore anyone with the back story (one is silver, one is black, one is damaged, one is not, one is currently on my rarely used TT bike, etc.)

    With the advice that it should be a reasonably easy job, I'm happy to have a tinker and swap bits about rather than just buy a completely new part.

    Kind regards

    Andy
  • lettingthedaysgoby
    lettingthedaysgoby Posts: 1,732
    As a sort of add on to this thread - I have a friend who wants to replace the 11-28 tiagra cassette on her bike to an 11-34 to make the hills a bit easier. However, her rear mech is a short cage so will need changing to a long cage one.

    Is it possible to buy just the "long" bit (and if so, where from?), or will she need to buy an entire new derailleur?
  • boblo
    boblo Posts: 360
    Yes. SJS do the spares. However, a cage will be nearly as much as a new long cage derailleur so she might be better off shopping around for a good deal on a cheap mech.
  • lesfirth
    lesfirth Posts: 1,382
    lettingthedaysgoby wrote:
    As a sort of add on to this thread - I have a friend who wants to replace the 11-28 tiagra cassette on her bike to an 11-34 to make the hills a bit easier. However, her rear mech is a short cage so will need changing to a long cage one.

    Is it possible to buy just the "long" bit (and if so, where from?), or will she need to buy an entire new derailleur?

    The difference between a "short cage" and "long/medium/GS" rear mechs is not just the cage length. The bottom bit of the parallelogram is much different. Changing the cage length will only alter the chain wrap . It will make no difference to the biggest sprocket you can use.
    I am all for messing about with bike bits and saving a few pounds when I can but a new 105 GS rear mech. does not cost much over £30.
  • lettingthedaysgoby
    lettingthedaysgoby Posts: 1,732
    The difference between a "short cage" and "long/medium/GS" rear mechs is not just the cage length. The bottom bit of the parallelogram is much different. Changing the cage length will only alter the chain wrap . It will make no difference to the biggest sprocket you can use.
    I am all for messing about with bike bits and saving a few pounds when I can but a new 105 GS rear mech. does not cost much over £30.
    Ah, good to know, cheers :)

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