Ventrac HQ680 Owner's/Operator's Manual page 14

OPERATION
Use of Duals for Mowing
On level to modest inclines, single tires will suffice. Single tires should be inflated to 7
psi and outside dual tires to 3-4 psi. Lower inflation pressure reduces grass and soil
compaction.
On significant inclines, even if only a small portion of the total mowing to be done, the
tractor should be equipped with dual tires for increased stability. If you are uncertain
about the need for duals, you should favor using them for your own SAFETY.
When using the mower deck, both traction boosters should be engaged to increase
stability and provide safer operation.
Note: Factory recommends heavy axle kit to be used with all dual installations.
C-5