I find it weird that your rear tires were more worn than your fronts. Typically front tires wear faster in a vehicle that has more weight in the front, unless you're burning out and I don't think you're doing that in your tracker
.
I haven't had my tracker on one set of tires long enough to need rotating but on other cars I would always swap the rears with the front. This would put the less worn tires on the front which is what you want. Being able to steer is more important than being able to go.ÂÂ