towing with suv???

My opinion of the 80% rule. I have towed heavy with a Dodge 150 pickup. Did it tow the weight? Yes, but it took it toll on the truck. Before 100K miles I had replaced the ring and pinion, transmission and several front end componates. The ride of the truck was harsh and the drive was not pleasant. While the 80% rule might not be writtren in stone I think it is a good guideline. This is nothing more then my opinion from experience.