105 front change

plowmar
plowmar Posts: 1,032
edited June 2011 in Road beginners
I'm posting on this Forum as I know that's what you all will call me. :oops:

I keep having problems changing to the bigger ring after taking hills with the small ring. In fact I have to get off and manually change the front ring.

From what I've just said you will gather that I am on the small ring and large cassette. As I cannot - or it won't let me - immediately change to the large ring on the down hill should I do a few change ups on the cassette before changing the front ring?

P S the change is fine - large front/ large rear - when on the bench without any stress on it.

(Sits back and waits for sarcasm, wit, disdain and hopefully some advice. ( to say what a plonker I am))

Comments

  • chiark
    chiark Posts: 335
    Yep, you've already hit the answer: simply shift on the cassette from the largest cog to near the middle, then shift front ring from small to large. You're asking the chain to do a huge amount of bending when in the large/large config, plus your rear derailleur might well be on the absolute limit of what it can provide in terms of length...

    Don't expect abuse in answers: it's a sensible question. There was a recent 'can someone explain gears' thread that's worth reading, too.

    I'm impressed you've managed 1800-odd miles and are having to get off to change: that would truly have done my nut in!
    Synapse Alloy 105 / Rock Lobster Tig Team Sl
  • plowmar
    plowmar Posts: 1,032
    Thanks Chiak.

    Have two bikes but usually only use the 50 large for the hilly rides and the 53/39 for flatter ones, its just it was doing my head in. But the hills are coming easier.

    re 'abuse' I just thought it was a stupid question by a silly contributor, so expected the worst. :wink:

    I'll try your idea and see what happens.
  • ollyridesfirst
    ollyridesfirst Posts: 486
    It could well be the same that happens to me. I have a compact 105 set, and when i go from 34 tooth to 50 tooth with the main brake level, i have to half click the paddle behind to bring thr front mech back a few mm. This stops chain rub in the 2 larger gears on the cassette....

    Thought about getting it looked at, but honestly it doesn't bother me that much
  • keef66
    keef66 Posts: 13,123
    Olly; that's the trim function. It's meant to work like that.

    Have a read of the instructions on Shimano Tech Docs
  • ollyridesfirst
    ollyridesfirst Posts: 486
    keef66 wrote:
    Olly; that's the trim function. It's meant to work like that.

    Have a read of the instructions on Shimano Tech Docs


    aaaaahhhhhhhh.....that does make a bit of sense i suppose :oops:

    nice one
  • keef66
    keef66 Posts: 13,123
    No need for the :oops:

    I'm guessing like me and 95% of new bike owners you didn't get any detailed instructions with the bike. I've downloaded lots of useful stuff from the Shimano site; setting up and using gears, exploded diagrams of front and rear hubs, installation instructions / parts diagrams for HT2 crankset / BB etc
  • ollyridesfirst
    ollyridesfirst Posts: 486
    I've got all the original boxes and instructions as i was properly fitted and went through every component with the bike shop that i bought my steed from, but as usual they just got thrown in a drawer in the garage!

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