Shimano Tiagra Chainset

AlahDamIt
AlahDamIt Posts: 44
edited August 2012 in Workshop
Does anyone know if a Shimano Tiagra Chainset FC4603 will replace a FC4600 without any other changes, my shifter and front mech are all tripple, im looking for the smaller ring. I cant find a smaller ring for the FC4600.
Bianchi infinito 2012
Specialized Secteur

Comments

  • Twostage
    Twostage Posts: 987
    Depends on your rear derailleur. For a 52/39/30 you'd really need the GS (long) version.
  • Erudin
    Erudin Posts: 136
    Looks like it will work as long as the rear mech (check its capacity) is sorted. I use a 45T capacity rear mech on my audax bike with a Tiagra triple and 11-32 cassete.

    http://techdocs.shimano.com/media/techdocs/content/cycle/SI/TIAGRA/SI_1MG0A/SI-1MG0A-001-00-Eng_v1_m56577569830746319.pdf

    http://sheldonbrown.com/harris/derailers-rear.html

    "For front derailers, when the derailer is mounted high enough to clear the largest chainwheel, there is a certain minimum size that you need for the smallest ring so that the chain won't be dragging over the bottom of the front cage. Different front derailers have different capacities depending on how tall their cages are. It is expressed in a number of teeth, which is the difference between the largest and smallest chainwheel. For instance, a 52/42/30 crank set would call for a front derailer with a minimum 22 tooth (52-30) capacity.

    For rear derailers, the capacity relates to the amount of chain slack the derailer can take up, and is equal to the front range (22 in the example above) plus the rear range. Thus, if you have a 52/42/30 crank set, and a 12-28 (16 tooth difference) cluster, the total capacity required would theoretically be 38 teeth (22 front difference + 16 rear difference). "
  • Twostage
    Twostage Posts: 987
    He says his front mech is already triple. So, like I said, it comes down to whether the rear mech is short (SS) or long (GS). Short is specified for a 16 tooth difference on the front chainrings, Long is 22 (52-30).

    http://techdocs.shimano.com/media/techd ... 746860.pdf

    Must admit I went triple on my tiagra 4400 setup without checking.
  • Thanks for the responses, I'm not sure wether to go ahead with this now, been struggling with the hills 1600ft climb over 3miles. Did the run on Monday this week and had to stop 3 times, did the same run tonight 2 days later without stopping. Time will tell. The hill is between Mortenhamstead and the Teighn Vally.
    Bianchi infinito 2012
    Specialized Secteur
  • Twostage
    Twostage Posts: 987
    I used to spend quite a bit of time down in Exeter, I like it down there. I remember thinking it was funny that you had a Teignmouth and we had Tynemouth.

    The hills do get easier.