Torvy
Super Member
I filled my tires with beet juice. I highly recommend it. The weight is low and off the axle.
Filled tires are great for helping with traction, but the ballast behind takes weight off of the front axle which is good for FEL counter balance. Your rear axle works like a fulcrum and the further back the weight goes, the greater the effect. Weight on your tires doesn't help that problem.
Personally, I use my flail as my counter. Heavy and sits back about 5 feet.