Gearing set up problems

ascurrell
ascurrell Posts: 1,739
edited April 2013 in Workshop
Hi Guys, wonder if I can pick your brains. Apologies if this has been asked before but any help would be appreciated.
I expect this is basic stuff that I should know.

After four years I decided to get my Airborne Lancer down from the loft, haven't ridden due to health problems.

Thought I would make a few changes to accommodate my lack of fitness and 100kgs.

Original set up was a standard 10 speed Ultegra 6600 with a 12-25 cassette.

I've got a newer [not new] 105 compact chainset and a 12-27 ratio cassette.

I've tried to set it up the front chain rings and mech change ok but doesn't seem smooth.

Worst of all is I can get the higher gears on the cassette but not the three lower ones.

Do I need a different rear mech,
is the chain compatible with the 105 chainset. Does the chain need to be longer?
I am thinking of changing the cables as well would that be advisable / necessary ?

As I said any help would be appreciated, I've adjusted all stops etc and no luck, also anything I missed please let me know,
Regards, alan

Comments

  • ascurrell
    ascurrell Posts: 1,739
    Any help appreciated, thanks
  • richiebones
    richiebones Posts: 379
    hi alan, check to see if your chain is the correct lenght for your new set up. put it in the large ring at the front and smallest at the back. the jocky wheels should line up vertically (at 90 degrees to the ground) if the arnt your chain is the wrong lenght

    changing from 25 to 27 at the back you will need to adjust the 'b screw' on the RD to allow the jocky wheel clear the cassette (youtube is your friend!)

    changing from a standard to compact you will need to drop the height of the FD to about 2mm above the longest tooth on the big ring to get smooth shifting

    if it were my bike id change the cable to the RD (and the loop of outer casing going into the mech)

    let us know how you get on
  • declan1
    declan1 Posts: 2,470
    hi alan, check to see if your chain is the correct lenght for your new set up. put it in the large ring at the front and smallest at the back. the jocky wheels should line up vertically (at 90 degrees to the ground) if the arnt your chain is the wrong lenght

    changing from 25 to 27 at the back you will need to adjust the 'b screw' on the RD to allow the jocky wheel clear the cassette (youtube is your friend!)

    changing from a standard to compact you will need to drop the height of the FD to about 2mm above the longest tooth on the big ring to get smooth shifting

    if it were my bike id change the cable to the RD (and the loop of outer casing going into the mech)

    let us know how you get on

    This ^

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • ascurrell
    ascurrell Posts: 1,739
    Hi Guys, thanks for the help and input, I don't think I will get to try those things for a few days but will definitely get back.
    There certainly is a few things there that I can try,

    Many thanks, alan