27.2 clamp for braze on front dereulleur ?

Kupepe
Kupepe Posts: 76
edited December 2013 in Workshop
Hello,

I got hold of a Colnago Super frame from the 70s. I am looking for a 27.2 clamp in order to use a braze on derailleur I own. I guess the downtube diameter is 27.2 since that was the tubing size from that era. If anyone has a different opinion please share. Anyhow, it seems I cannot find any clamps of that size from the major online stores. Anyone has any idea where to get one ?

Kind Regards

Nick

Comments

  • BillyMansell
    BillyMansell Posts: 817
    Best to measure the external diameter. 27.2 could suggest the internal dimnesion as that's a standard seatpost size of the time although I may be wrong as even I'm not that old.
  • nicklouse
    nicklouse Posts: 50,675
    you will be needing a 28.6mm clamp
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  • maddog 2
    maddog 2 Posts: 8,114
    +1 what Nick said
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  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    28.6 seems more likely to me too
    left the forum March 2023
  • smidsy
    smidsy Posts: 5,273
    As you say 27.2 is often the seat post size but that is measured inside the frame tube.

    You need the outside dimension as the clamp fits around the outside of the tube, not inside it.

    As others state above it is likely to be 28.6 (based on the anticipated tube wall thickness) but best to check.
    Yellow is the new Black.
  • Monty Dog
    Monty Dog Posts: 20,614
    There are only 3 standard clamp-on sizes - 28.6mm and guess it has to be Super Record?
    Make mine an Italian, with Campagnolo on the side..

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