Originally Posted by vpiuva
Tim, are you talking about the "hidden fifth" feature? If so, I've taken non-h5 rings and used them on my older 135mm record cranks - for the large ring I just take a pair of pliers (or maybe it was a drill) to that CPSC pin [that prevents your chain from wedging in the crank arm] and remove it.
Or is one spider arm actually not equidistant?
Nope, not hidden fifth (which is also used in Ritchey cranks, and some from Sugino). That feature doesn't necessarily put the bolt-hole at a different spot.
What Campy does with their "110mm" compact double is slightly shift one of the holes on the spider slightly off, which means
a) you can't rotate the chainrings on the spider (fine, and it's just a "more enforced" version of having rotational indicators that most other chainrings do)
b) you can't use anyone else's chainrings unless you either machine them, or machine the spider.