I have a lot of slopes on my property and at times have difficulty maintaining good traction with both wheels.
Here is an old thread that addressed something similar:
To start I changed my rear tires to Carlisle HD Field Trax. I tried bar treads on my previous Z and they were ok until the ground was dry and then they were worse than the turf's.
They are an improvement over the stock turf tires however you have to be a bit more careful turning. Dieselshadow's School of Z Driving taught me how to make smooth 3 point turn and this helps.
In many places I am on a slope making the turn or steering around an obstacle and sometimes I don't have enough traction to pull off a good turn and a wheel spins.
I have found that the left wheel has better traction than the right due to the location of the fuel tank. I wish the tank had dual cells over both tires.
Today I filled the rear tires with windshield washer fluid. Five and a half gallons per tire. I think I can get another half gallon in each tire but I only purchased eleven gallons. If this works, I'll get another gallon and top off each tire. I have intended to do this since last year but never got around to it. My last time mowing I lost traction on a turn and slid into the propane tank. That prompted me to get off my lazy butt and fill the tires.
I also have several pieces of 3" x 1/4" bar stock that I cut to length for a rear weight bumper. Yes that has been cut and on the work bench since last year as well... I have several pieces of steel from other projects and just can't see spending the on the factory rear weight so I am going to make my own. The advantage is I can add or subtract pieces till I get it right. As Gizmo posted in the other thread, some weight will have to be added up front to prevent wheelies.
My next step is to get it drilled and mounted. It will take a trip to Fastenal or a similar supply house to get some metric all thread an the appropriate nuts.
In the meantime I may do a test mow to see how the fluid filled tires perform. I am also curious if this improves the ride as well.