105: 5600 Double 50/39 V 5603 50/39/30

daniel_b
daniel_b Posts: 11,746
edited December 2008 in Workshop
Gentlemen, after your help I have pretty much decided on an HTII 105 crankset.

My reason for changing is that I want a lower gearset than my current 53/42, and ideally I would have liked a 53/39/30 type setup, as I like the big gear at the front, but these seem to be thin on the ground.

Which led me to the 2 options in the poll.

My sensible head is thinking why would I pay an extra tenner for less kit, and in reality if I want to save the weight, can I not just remove the inner ring??
And is the 5603 not a marginally newer version than the 5600 double?

Or am I missing the plot entirely...........

Dan
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18

Comments

  • whyamihere
    whyamihere Posts: 7,708
    While you can remove the extra ring, the crankset will be set further out from the frame, giving a higher Q factor. On Hollowtech 2 cranks, you can't just buy a shorter BB if you take a ring off, you're stuck with the length it is.

    Shimano's numbering is like this:
    First number is model family (5 is 105, 6 is Ultegra etc)
    Second number is the revision number (56xx is the 6th edition of 105)
    The last 2 numbers are minor model variations. 5600 is just the designation for a standard double, 5603 is a triple, I have a feeling 5650 might be the compact, but I could well be wrong there. 5600 and 5603 are the same age.
  • Daniel B wrote:
    I would have liked a 53/39/30 type setupDan


    I'd go for one of those as well, nice bit of range for the winter beast 8)
    What cassette do you have with it?
  • daniel_b
    daniel_b Posts: 11,746
    Thankyou for your replies,
    whyamihere wrote:
    While you can remove the extra ring, the crankset will be set further out from the frame, giving a higher Q factor. On Hollowtech 2 cranks, you can't just buy a shorter BB if you take a ring off, you're stuck with the length it is.

    Whyamihere, what's the Q factor, I assume the distance the cranks are outside the BB?
    Is it to do with the amount of flex you are likely to get?

    Stefanos, the rear cassette it will be using is a 105 12-25.

    Though I see you can get 11-25 rears so long term that could potentially get rid of the top gear issue - no issues with an 11 tooth rear cog is there?

    Dan
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • whyamihere
    whyamihere Posts: 7,708
    The Q-factor is essentially the distance between your pedals. No relation to flex. The greater the Q factor, the further apart your feet will be. Large Q factors are obviously less aerodynamic, and can be quite uncomfortable. You're unlikely to notice it much to be honest, but I'd still go for a proper double rather than removing the granny ring from a triple if you decide it's a double you want.
  • Myk-ee
    Myk-ee Posts: 276
    Why not try a 50/34 compact crankset? It comes in the 105 guise. You'll need to shorten your chain by 1 or 2 links and lower your front derailleur, its a fairly straight forward process.
    It's the vibe of the thing.
  • aracer
    aracer Posts: 1,649
    It really depends whether you need that little 30 ring or not. If you do, then the double will be rubbish.

    If you want a slightly bigger ring, and don't mind the slightly bigger middle ring, there is always http://www.chainreactioncycles.com/Mode ... elID=11796 though, which whilst a bit older is nominally better quality than what you're looking at, and will work out a tenner cheaper including the BB in the size you want. Also has the advantage that you can remove the inner ring and use a double BB instead of a triple for the same Q-factor and a miniscule weight penalty over the double (the arms are the same apart from the inner ring tabs). I reckon it looks nicer too, hence why I've just bought one for my winter bike, given I've never had any problems with Octalink BBs on road so don't reckon there's any advantage to HT2. Oh, and I'm pretty sure it will work with 10-speed.