Originally Posted by ProStreetCamaro
You got it. If the deck is absolutely perfectly level flat it will create the most vacuum and cut the cleanest.
As a par time cutter over most of the last decade+ I've had more time to play with these things than a lot of guys get a chance to do when they're running a full schedule. I've played around a ton with this stuff during that time and a little forwards pitch provides a better looking cut and much better looking stripes. Sometimes as little as 1/8" of change in pitch can make a HUGE difference in striping abilityy, so a little experimenting around with your own machine by starting at what the manu suggests, then going up or down from there, and you'll find the sweet spot. Like I said above, the manu's give a suggested
pitch, but you have to find what works best for your lawns and machine/blade combo.
As far as having the deck flat giving the best vacuum- I disagree. If you take a shop vac and place the nozzle flat/tight over something, the vac motor starts really screaming to try to suck in any air. If you crack just one side up off that suurface, you get way more suction, and the motor works less to provide it.