What is the primary purpose of dual rear tires?

Answer 1

The main purpose for Dual rear tires is for 2 basic reasons. 1. When towing a heavy load, it lessens the chance of over stressing the rear tires (In extreme cases, the blowout of the rear tires) 2. It provides more traction in all situations (by having more rubber on the road, the torque put out by the engine is displaced in more surface area than single rear tires) I'm sure a true expert can put it into better words, but there's a basic answer.