# Type A & B chainrings



## Jeff G (Jul 22, 2005)

What does the "A" and "B" type signify? Is one for a double crankset and the other for a triple?


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## Dave Hickey (Jan 27, 2002)

I don't know is it's still true, but they used to be certain chainring pairings. A was 53 x 39 and B was 52 x 42 or visa versa


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## hclignett (Dec 18, 2006)

According to the shimano tech doc's;
A=42T small ring
B=39T small ring
E=44T small ring

They don't mention type for the triple, I only just checked the Dura-Ace models though.

hc


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## toyota (Sep 4, 2006)

A and B corresponds to matching chainring set. There is an A 53 and A 42, then there is an B 53 that should be used with a B 39. In other words the different big rings are ramped to shift better with the specific smaller rings.


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## MWT (Nov 12, 2002)

toyota said:


> A and B corresponds to matching chainring set. There is an A 53 and A 42, then there is an B 53 that should be used with a B 39. In other words the different big rings are ramped to shift better with the specific smaller rings.


I wonder if the difference in shifting performance is discernable.


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## Jeff G (Jul 22, 2005)

*Thanks for the help*

Yep the A & B are to be used together. A large (or outside) "A" with a middle "A"ring and the same with the "B" type. According to Sheldon Brown the rings can be mixed without much problem. The shift pins would be little out of sync if you mixed an "A" ring with a "B" ring but there really shoudln't be any noticeable difference in shifting from the middle to the outer ring. I just ordered them to match, guess I'm more anal then others.


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## omniviper (Sep 18, 2004)

ahhhh thanks for the clearup!

before i thoguht a rings were DA rings while B ones were ultegra. Then i bought DA cranks and saw it had B rings instead. It shot my theory down


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## uzziefly (Jul 15, 2006)

I didn't know there was a type A and B


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## Mark McM (Jun 18, 2005)

*Type A and Type B chainrings*



uzziefly said:


> I didn't know there was a type A and B


Type A chainrings are more competitive and assertive, the "alpha" chainring in the bicycle world. Type B chainrings are more layed back and don't take things as seriously.


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## uzziefly (Jul 15, 2006)

Mark McM said:


> Type A chainrings are more competitive and assertive, the "alpha" chainring in the bicycle world. Type B chainrings are more layed back and don't take things as seriously.



And this means? :idea:


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## Mark McM (Jun 18, 2005)

uzziefly said:


> And this means? :idea:


Type A and Type B


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