Well they are stated in the manual and on the fuel cap, yet they both contradict each other

Unladen
37 front, give or take
34 rear, give or take

Laden
40 front
41 rear

Thats what I have found best, without sounding gay there is a small difference if the fronts are 38 at the front when unladen. It feels really responsive but I think you may wear the middle of the tyre out a bit too quick.