question re "tandem" crank arms (sugino xd's)
ok. now. i was browsing QBP's catalog, looking for something cool as far as sugino XD's go. i saw they listed crankarms for tandems, xd600's. these are pretty much what i want, being that i want to throw my own rings on 'em, but i'm terribly frightened that the fact that the things are made for tandems, they might not work on my regular, solo-bike application.
is there really a difference?
i also saw some xd500's, as a compact double, for a half-sweet price, and i was pleased to note that they've got alloy rings and the gearing is almost what i want, but i a worry that they're 8spd. i know, i know; many folks run 8spd cranks with 9spd cassettes, but if it didnt work, i'd feel silly. anyone know if the xd500's are 8spd? the quality catalog doesn't say, and surprise, surprise, the bike shop doesnt know.
so, to recap: what's the difference between tandem sugino xd crank-arms and regular xd crank arms? are the xd500's with the 50/36 rings 9 spd-compatible?