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DA 42 Tooth Chainring(5 posts)

DA 42 Tooth ChainringCitius
Sep 15, 2002 3:56 PM
Are the Shaimano DA inner chainrings interchangeable? I currently have the DA crankset that came with a 39t for the inner, but I would like to swap it for the 42t.

Thanks to the wise
re: DA 42 Tooth ChainringJuanmoretime
Sep 15, 2002 4:15 PM
You can put a 39 on but you may have to replace the big ring too. They come in 53 tooth A + B, one is design to work with the 42 tooth ring and the other with the 39. I beleive they differ in location of the shift pins and lift teeth. For all I know it might just be Shimano propaganda.
Sep 16, 2002 4:40 AM
On the Shimano groups, A refers to triple and B to double (or maybe its vice versa, I forget). The double ring has no ramps. If you have a double (which it sounds like you do), just make sure you buy a double ring. You do not have to buy a new large ring. The large B ring works with either the 39 or the 42 (you can even get a 38 from Sugino).

When installing it, there is a little triangle on the ring that should be under the crank arm. Same with the big ring.

It is very easy to install, don't be afraid to do it yourself. A 42 is much nicer than a 39 when on flat or slightly rolling terrain.
re: DA 42 Tooth Chainringmerckx56
Sep 16, 2002 6:58 AM
if you look at your big ring, it'll probably have a "B" on it. the "A" and "B" only references which setup the cranks initially came with. a 53/42 will have an "A" while a 53/39 will have a "B". the chainrings are interchangeable, regardless of which letter is on them. shimano says that the letters must correspond but it's pure hoo-hah! i just put a 42 on my "B" dura-ace crank and it shifts perfectly! you have to move your front derailleur too!
interchangeable, despite what Shimano saysDougSloan
Sep 16, 2002 7:11 AM
I change these things back and forth with no consideration of what goes with what. I even use after-market rings with no shift pins or ramps at all. I currently have 54 large ring made to work with a 44, but with a 39 small. I even run a 39/56 sometimes. It might not be absolutely perfect, but everything works fine. Give it a go.