We've been looking for ways to combat planter pinch row compaction so last year we did a side-by-side field trial that compares planting with VF tires (which run at 40% less air pressure) to standard radial tires. Even though we had nearly perfect growing conditions all year, we still had some interesting finds with this field trial...

You can check it out here:
www.ntstiresupply.com/ptk-shared/does-it-pay-to-plant-with-vf-tires