I guess the answer here is something like a ski lift powered by the handcarts going downhill.
If you need to push it, you can push a cargo bike probably easier than this.
If you're really worried about rolling resistance give it suspension.
I would have asked them why they didn't make a 3 wheeled version. Keep the two big wheels on the side, add a smaller freely rotating one in the front, like a lot of strollers have. They could make it just a tiny bit too low, so it's easy to roll it with both 2 or 3 wheels.
I guess tl;dr: I dunno what these guys are going on about and wonder if they've ever actually tried a 4 wheel cart.
HN comments at https://news.ycombinator.com/item?id=17792329 and https://news.ycombinator.com/item?id=4285086 .
Rolling resistance = Crr * N where N = the normal force a.k.a. the weight bearing down on the wheel for a slow moving cart. If you use the same tires but double the axles you reduce the weight on each wheel by half leading to about the same rolling resistance for the vehicle as a whole.
> its narrow wheels minimize rolling resistance
This is a myth that has gripped the bicycle industry for decades but has been slowly dying over the last two. Fat tires have slightly lower rolling resistance at the same pressure and a smoother ride at the same rolling resistance. It takes more energy to lift a hard wheel over a small bump than for a softer wheel to deform and lift less so the difference becomes greater as soon as the road isn't perfectly smooth.
The main reason road racing tires only got a little fatter and aren't as fat as say e-bike tires is aerodynamics which is hardly applicable to hand carts.
> Unlike a van or a car, my handcart doesn’t need gasoline, electricity, or batteries, making it entirely independent from energy infrastructures.
TANSTAAFL - you're going to need more calories to compensate for the additional effort you're expending to move your handcart. Human food is far from the cheapest fuel and few people are able to obtain it "entirely independently from energy infrastructure."
There is a guy ( Nicolò Guarrera ) who completed a world tour by walk and his tool of choice to transport stuffs was a trekking stroller.
