They are not truly pulling as the rig is motor assist. It’s what I call DogMotoSports so all dogs at almost any age can participate and all peeps can do it as well even some with physical disabilities. The trail is mostly level and the wheels roll easily also so they can power it some if they want….here’s the breakdown to your question: the bike is approximately 65 pounds and with dog apparatus I’ve designed about another 25 pounds accessories and what not another 15 pounds so I would say 100 pounds or so. Add my weight and we are approaching 275ish… 4 dogs are capable of comfortably hauling about 3 times their weight so each dog is about 50 pounds so 150x4 is 600 pounds so the whole setup figuring high is 300 pounds or so. About 1/2 of what they can comfortably pull. Hope that all makes sense: