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Shiman Ultegra chainring type A

PhideauxPhideaux Posts: 87
edited March 2009 in Workshop
Please, what is the difference between the standard Ultegra chainring and the type A chainring? I can't find an explaination on the Shimano exploded diagramme ... 621036.pdf

If I need to replace an old set of chainrings with new, which should I order (they appear to be the same price).

And looking at some of the suppliers they refer to Type A and Type B... :?: (I now believe that the Type B is only for the 6500 series rather than the 6600)

Whether you think you can, or whether you think you can't, you're probably right.


  • i have a dura ace 9 speed (7700) which is type b, if you look closely at your chainring where it says shimano you should see something like B 53, B being the type and 53 being the amount of teeth.
  • itboffinitboffin Posts: 19,964
    I asked the same question a few months ago but alas no one came to the rescue, having both type A & B i can now only assume that its because one is for compact and the other for double both of which having different BCD 110 vs 130 so not interchangeable as I found out to my cost.
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  • chuckcorkchuckcork Posts: 1,471
    Got this from here:, response to such a query by Sheldon Brown no less.

    > Hi all,

    > A question about Shimano Ultegra chainrings. I currently have a 53"B"
    > large ring and a 39 inner ring. I want to change the 39 to a 42. I'm
    > told that I must replace both the outer and inner rings because I have a
    > "B" 53 ring and it's incompatable with the 42 inner ring. As I
    > understand it, the 53"A" large ring must only be used with the 42 inner
    > ring, and the 53"B" ring must only be used with the 39 inner ring.

    > I have spoken to several bike shops about the importance of sticking to
    > this "A" = 42, "B" = 39 concept, and I get reactions from, giving me a
    > strange look and tell me it doesn't make any difference, or that they
    > never heard of such a thing. Other people, mostly knowledgable riders,
    > say that if I want to retain great shifting, I should follow these
    > guidelines.

    Until a few years ago, there was no such thing as matched chainrings,
    and it wasn't a problem. When Shimano introduced their "Superglide"
    chainrings, they were matched, and this does, indeed, provide slightly
    smoother shifting. It is, however, far from a necessity. My advice is,
    if you're bound and determined to go to a 42, just put on the 42 and try

    If you find the shifting satisfactory, you've saved the price of a
    chainring you didn't need.

    If you find the shifting less than satisfactory, you can always buy a
    new 53.

    If it were me, and I found the 39 x (whatever) too low for the terrain,
    I'd look into a tighter rear cluster (unless you've already got a
    corncob) instead.

    Sheldon "Is 42 Really The Answer?" Brown
    Newtonville, Massachusetts
    'Twas Mulga Bill, from Eaglehawk, that caught the cycling craze....
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