Front shifting

DeVlaeminck
DeVlaeminck Posts: 9,104
edited August 2018 in Workshop
11 speed Ultegra mech and shifters, not sure what series but the front mech does not have a screw to adjust cable tension.

Cable is routed to the left (as you look from behind) of a little pin on the mech and the right of the securing bolt.

Rings are Praxis 50:34 and cranks 3D Rotor sold as compatible with 11 spd Ultegra with a power2max power meter.

Problem is a reluctance to shift up to the big ring. It's as if the cable has to be so tight and move the mech so far it is then impossible to eliminate cable rub in several sprockets.

It's annoying me, I can ride the bike but the shifting is worse than on my Tiagra knockabout bike. I've tried moving the mech up and down, it's braze on but tried angling it.

Is there something I'm missing, is this typical of moving away from shimano rings, is there another series of Ultegra and this would work great with that one but not mine?
[Castle Donington Ladies FC - going up in '22]

Comments

  • i.bhamra
    i.bhamra Posts: 304
    Try routing the cable the other side of the pin (and/or possibly the other side of the pinch bolt). Depending on the rest of the cable routing around the BB on your specific make and and model of bike, the way you've described your cable attaching to the mech may not be optimal.

    Also when cable disconnected set your low limit so the chain only just clears the mech cage when in the small (front) and largest (back) ring/sprocket. For shifting, there should be just enough cable tension to take out any slack when in the little ring if the rest of the setup is good. If you don't have cable stops for a barrel adjuster you might want to fit an in-line one to help get the tension right.
  • DeVlaeminck
    DeVlaeminck Posts: 9,104
    Thanks both. I've tried again and reached a point of "good enough". I think perhaps on this set up chain rub in big big and big next big us the price for having it upshift cleanly. I'll test it out on a chain gang tonight, if I get stuck in the small ring it's going in the skip!
    [Castle Donington Ladies FC - going up in '22]
  • StillGoing
    StillGoing Posts: 5,211
    You should have an inline barrel adjuster on the front derailleur cable in order to get the correct cable tension. You can pull the cable as tight as you like without one, but it won't do the job properly.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • DeVlaeminck
    DeVlaeminck Posts: 9,104
    Yes I have been using that though I can pull the cable more than tight enough without it so that's not the issue.

    I think maybe I've been used to Chorus which allows for greater triming of the mech which helps eliminate chain rub - anyway having set the low limit screw a bit closer to the chain as advised and it is not too bad now.
    [Castle Donington Ladies FC - going up in '22]
  • jermas
    jermas Posts: 484
    When installing the cable on the FD ensure the shifter is set to its lowest trim setting ie an extra (small lever) press. If it's not set this way, the cable doesn't have enough range to shift up to the big ring.
  • StillGoing
    StillGoing Posts: 5,211
    Yes I have been using that though I can pull the cable more than tight enough without it so that's not the issue.

    http://si.shimano.com/pdfs/dm/DM-RAFD001-02-ENG.pdf
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Vino'sGhost
    Vino'sGhost Posts: 4,129
    Setting up the FD is one of those tasks that should be simple but frequently isn’t.

    I’d start from the beginning and you should end
    Up with a free moving mech with loads of trim. The Ultegra kit does seem sensitive to cables. I bought a da gear and brake cable kit that was expensive but has made a world of difference.
  • It's worth checking that the black plastic skid plate hasn't fallen off or worn through. I lost that on my CX bike and I suffered terrible problems with front shifting ... having to increase tension to be able to get the big ring and then trim position wouldn't work reliably and downshifting was problematic.

    Got a new skid plate and put it in, then followed the "install" instructions for the derailleur and it was back to shifting fine again. So worth a try.

    This is what I'm talking about:
    https://www.sjscycles.co.uk/gear-spares ... y5p116000/