Hey - I have a Trek 11i computer too! I think it's great, with the nice big screen.
Anyway, I had lots of extra wire with mine. I have a 15" hybrid, so maybe my frame is much smaller than yours. Do you have a huge frame? You're setting it up with the speed sensor (long wire) on the chainstay (at the back wheel), and the cadence sensor (short wire) going to the crank, right?