Shimano Chain Rings A, B and D

spenb
spenb Posts: 14
edited May 2013 in Workshop
Please Help,
Last time I rode was about 20 years ago when equipment was easy.
I have a 2nd hand 105 double octalink chain set with type B rings.
The outer ring was worn and a 53T, in my wisdom I have brought a type D 50T off a 105 Triple.
I notice this does not have a recess for the bolt head to sit in.
Does this really matter and being a D type will it work?
Thanks,
Spen
I'm not BITTER - Just TWISTED

Comments

  • ricky1980
    ricky1980 Posts: 891
    the 53T has a 130mm BCD (Bolt Centre Distance) where the 50T has 110mm so the 50T won't fit on your ring.

    You need to get a ring that has 130mm BCD then it will fit perfetctly
    Road - Cannondale CAAD 8 - 7.8kg
    Road - Chinese Carbon Diablo - 6.4kg
  • mister p
    mister p Posts: 405
    Actually the 50T off a triple does have a 130mm BCD.

    That ring will work of a sort but it is not designed to work with the shift ramps on your existing smaller ring. I once fitted a 52T triple outer when I couldn't get a 52T double ring and the shifting was nowhere near as nice as it should have been.
  • spenb
    spenb Posts: 14
    Thanks,

    Its on a new/old/used miss mash build.

    Yes its a 130 pcd - so brought it to lower the gears slightly.
    I will be running Dura ace 10 speed bar end shifters and believe the left lever on these are friction so Will be feeling my way over to the big ring so I might be ok then?

    Thanks again
    I'm not BITTER - Just TWISTED
  • andy_wrx
    andy_wrx Posts: 3,396
    It'll be fine

    Read what Sheldon says about type A & B from 53/39 & 53/42 doubles
    http://sheldonbrown.com/dura-ace.html
    - type D is equivalent from a triple 50/39/30

    The teeth, ramps, pins, etc on a matched-up set are designed to give the optimum gearchanges, but if not matched then they'll still work fine - if you notice any difference at all...

    Someone else asking sort of same question earlier
    viewtopic.php?p=16142215

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