Shimano Right-Hand Ultegra ST-6700 Shifter Ratchet Slipping

burgesstribe
burgesstribe Posts: 2
edited November 2015 in Workshop
Hi, my Shimano Right-Hand Ultegra ST-6700 Shifter is intermittently slipping gears when trying to shift to the lower gears (i.e. larger cogs, cable under tension, using large lever). I've changed the cables as the prior one was fraying (in the shifter guide, so I thought this could be the cause) using top-spec Dura-Ace 9000 (polymer coated) but the problem is still there. Looking at the mechanism during shifts, it is clear that the part that is meant to catch on the ratchet wheel (pawl?) is occasionally slipping over the teeth, due to teeth wear / excessive freeplay (if I apply downward pressure to help maintain contact, it doesn't slip).

Clearly I could spend money to buy a new shifter (from £80 in UK) but does anyone have advice on how to fix e.g. putting a 'shim' in place to prevent the pawl from moving away from the ratchet wheel? Or advice about buying 2nd hand (I'm a bit reluctant given my current issue)?

Note: the bike is 2nd hand - I've probably done about 300miles only & I don't know its history - but it does seem surprising to me that Ultegra shifters should wear out in this way... perhaps I should write to Shimano to see if they'll replace at a discount?

Comments

  • corvusxiii
    corvusxiii Posts: 26
    If you remove the lever, 5mm Allen bolt I think, you will get access to to a smaller Allen bolt that acts as an axel for the rotating barrel. If it's loose it might be a quick fix. Doubt it though.
  • Rightarmbad
    Rightarmbad Posts: 216
    If you have had a cable fray in there, check for some small bits of old cable getting in mechanism.

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