The little tab, that should normally line up behind the crank arm, apparently designed to stop the chain from getting stuck behind the crank arm on an overshift (which theoretically shouldn't ever happen anyway, since the FD limit screw will be set correctly haha), cannot line up behind the cranks I have, probably because they're not designed to go together. It's all 135BCD, but the new chainring is obviously for a newer (at least, different) crankset.

My question: is this any serious technical problem, or more-or-less a cosmetic issue? Would it bother you? Discuss

(btw, the tab on the outer chainring is directly above the chainring mounting bolt at 11 o'clock, between "10 SPEED" and "CAMPAGNOLO".)

a <C> hidden 5th arm behind the crank chain ring you have there Is my guess ..

do what pleases you..

If only... but alas, no hidden arm.

I've just checked the old chainring (pulled it out of the recycling bin), and the tab is oriented differently, it's between the mounting bolts, so it goes behind the crank arm when mounted. Interestingly, the old chainring's tab can be removed (small torx screw) and there's an alternate mounting hole for it inline with a mounting bolt, so that chainring could have the tab moved to accommodate either style crank.

Maybe this post can help someone in the future: if you get new 135 BCD campy chainrings, and go from 52 to 53 teeth, the little tab that goes behind the crank arm may not be in the same place on the chainring, and you may not be able to move the tab.

I suppose I could drill a hole in the new chainring and use the old chainring's tab... I'll save the old chainring in case I feel frisky this weekend.

That would be the easiest and best solution IMHO.

The "anti-jam pin" unscrews, or at least it does in the TA chainrings I use (pin held in place with a small recessed nut on the inner face of the ring). I switched from a standard 5 arm Campag crank ('98 Chorus) to a "hidden arm" crank ('05 Chorus). I drilled a new appropriately-positioned hole in the chainring, used a Dremel to hollow out a small recess for the nut and transferred the pin. That was two years ago. However, I've never dropped the chain off the outside of the chainring, so it may not have been necessary