Treble to Double chainset

monster-mash
monster-mash Posts: 586
edited May 2011 in Workshop
Just fitted a double for a treble chainset. Went to set up the front mech and found I was struggling anyway next thing the STi starts to play up and now the return lever only returns halfway and the main doesn't increment.
Not compatable I assume oh and its all Ultegra bar the front mech which is 105
Any Idea's / suggestions

Comments

  • desweller
    desweller Posts: 5,175
    It should work, I use my triple mech + shifter with a compact no problems.
    - - - - - - - - - -
    On Strava.{/url}
  • tim_wand
    tim_wand Posts: 2,552
    I ve got full 105 triple levers working on a double chainset. The only thing I ve had to do is reign in the High and Low adjusters on the front mech. If anything the extra travel on the front mech STI helps me to trim the mech.

    This being the case the only thing I can think of is the axle length in your bottom bracket do you know what it is anything over 111 mm might give you problems as longer axle lengths are designed to give you the right Q distance for each chainset and bottom bracket.

    Take it we are talking about a standard 53/39 double chainset here so other than axle length there really should be no issue.
  • monster-mash
    monster-mash Posts: 586
    Compact 34 / 50 suppose the lenght

    May need a nother look at the STi may have strained it and locked it up - not sure whta to do with it.
  • tim_wand
    tim_wand Posts: 2,552
    Doubt you will have buggered the STI. Detatch the cable from the front mech and hold it between your finger and thumb under tension. Shift the shifter and see how many times and how much cable it takes up. If its a triple shifter I doubt it wont take up at least two shifts of cable length which is all you need. (if it take three then this can still be trimmed out with the high and low adjusters on the front mech)

    Still think the problem is the axle length of the bottom bracket. if it was originally put on to handle a triple (about 127mm) then putting a double chainset either standard or compact on it will have moved the chainrings out from the bottom bracket and upset indexing.
  • ride_whenever
    ride_whenever Posts: 13,279
    Although if an external BB then it's more likely a dead shifter,
    Neeermad
    Carbon 456
    456 lefty
    Pompino
    White Inbred
  • monster-mash
    monster-mash Posts: 586
    Just back from a ride so will now take a look. Biggest problem is the STi I am hoping that its no shafted tried holding the cables creating tension (Tim Wind) this did nothing so may need closer inspection.
    Let you know may just be jammed, its the wifes bike (winter thankfully) I don't need to tell you about the earole bending I am getting (lol) :D
  • ride_whenever
    ride_whenever Posts: 13,279
    Try to take the cable out, if it isn't coming out then you'll need to be really careful as they aren't very easy to reassemble once they're in pieces.
    Neeermad
    Carbon 456
    456 lefty
    Pompino
    White Inbred
  • monster-mash
    monster-mash Posts: 586
    Thanks for your help all but as I suspected with a little more investigation there was a piece of metal had broke away that looked as it retained a small spring why this happened I have no idea can only put it down to wear & tear perhaps although its 3 years old approx 2000 miles.
    Was going to go looking on ebay for a broken one perhaps to mess about with although it looks like the inside of a medioca Swiss watch in there then found that Merlin had the left side 6600 in clearence for £35

    May go down the line of looking for broken one if nothing more than education, sounds like you had fun Ride-Whenever then again its not as if I have nothing to do all day

Categories