Front shifts are a weakness with tandems. I would highly encourage you putting a chain catcher on the bike to save from a dropped chain. Our bike is temperamental on the front shifts we have to give a very slight pause before adding pressure along with not shifting into the small ring with the chain too far down the rear cog. We've found that it doesn't take too much pressure on the peddles to create an issue on our front shift. We are using 9 speed Race Face cranks with a XTR front derailleur.