Even if you do use the 32 cog, the Alivio will work - I have and it works just fine. In fact most rear derailleurs are conservartively spec'd i.e. the 27max 105 RD works just fine on 28s, 30s as long as the b screw is set properly.
Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
Originally Posted by freeranger
The Shimano Alivio rear der. is only spec'd for 30T. Why not use it with a 32T, since it won't (shouldn't) see the large-large combo anyway? (or is shouldn't the definitive word here?
The issue is the possibilty of the upper pulley rubbing the biggest cog. Up to a point you can adjust that out with the "B" screw on the back of the derailleur mount. Doesn't have anything to do with chain wrap or big/big combinations.