Ok the first set of pics is a 05 driven sheave (left) and the 06 (right)..
Note the tapered part of the sheave are the same size, but the 06 has a flat part down by the helix that the 05 sheave does not.. This is your extended portion, now in theory this should allow the belt to travel further down the secondary before it starts to clean the helix, thus allowing the belt to travel further up the primary.
[attachment=98039:attachment] [attachment=98038:attachment]
Note the tapered part of the sheave are the same size, but the 06 has a flat part down by the helix that the 05 sheave does not.. This is your extended portion, now in theory this should allow the belt to travel further down the secondary before it starts to clean the helix, thus allowing the belt to travel further up the primary.
[attachment=98039:attachment] [attachment=98038:attachment]