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What size band-on? Front Derailleur

luke5495luke5495 Posts: 16
edited April 2016 in Workshop
Hi there,

I have measured my seat tube and it comes in at 105mm, which divided by 3.14 as people said comes in at: 33.44mm.
I am looking at getting a Shimano Ultegra Band-on, these come in sizes of: 28.6/31.8mm & 34.9mm. Do I go for the smaller first one? Or the larger second one?

Many Thanks,

Luke

Posts

  • arlowoodarlowood Posts: 2,379
    luke5495 wrote:
    Hi there,

    I have measured my seat tube and it comes in at 105mm, which divided by 3.14 as people said comes in at: 33.44mm.
    I am looking at getting a Shimano Ultegra Band-on, these come in sizes of: 28.6/31.8mm & 34.9mm. Do I go for the smaller first one? Or the larger second one?

    Many Thanks,

    Luke


    The second larger on. The smaller one comes designed to fit seat tubs of 31.8mm external diameter with a couple of rubber inserts to reduce the size for narrower (usually steel) seat tubes.

    Don't worry about the fractions of mm difference in your calculation - need the larger 34.9mm version.
  • luke5495luke5495 Posts: 16
    Thank you Arlowood :). I can finally get rid of my Sora, good ridance!
  • ugo.santaluciaugo.santalucia Posts: 24,243
    luke5495 wrote:
    Thank you Arlowood :). I can finally get rid of my Sora, good ridance!

    You will find that the Ultegra is no better. Front derailleurs are simple creatures... you can pay very little or very much and they do exactly the same thing in the same way. I have a Tiagra one, which is brilliant
  • keef66keef66 Posts: 13,286
    luke5495 wrote:
    Thank you Arlowood :). I can finally get rid of my Sora, good ridance!

    You will find that the Ultegra is no better. Front derailleurs are simple creatures... you can pay very little or very much and they do exactly the same thing in the same way. I have a Tiagra one, which is brilliant

    The latest generation Shimano ones with the longer arm are noticeably better than their predecessors (Tiagra 4700, 105 5800, Ultegra 6800). But then you need the corresponding shifters, so it's not a cheap fix.

    Prior to that I'd agree; apart from minor weight savings and possibly a more durable finish, you'd get nothing in terms of a performance improvement by buying a dearer model front mech.
  • keef66 wrote:
    luke5495 wrote:
    Thank you Arlowood :). I can finally get rid of my Sora, good ridance!

    You will find that the Ultegra is no better. Front derailleurs are simple creatures... you can pay very little or very much and they do exactly the same thing in the same way. I have a Tiagra one, which is brilliant

    The latest generation Shimano ones with the longer arm are noticeably better than their predecessors (Tiagra 4700, 105 5800, Ultegra 6800). But then you need the corresponding shifters, so it's not a cheap fix.

    Prior to that I'd agree; apart from minor weight savings and possibly a more durable finish, you'd get nothing in terms of a performance improvement by buying a dearer model front mech.

    +1 - much better, I'm running Sora 9 spd, 105 10 spd and Ultegra 11 spd, the Ultegra is effortless and very short throw of the lever.
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