Rediscovering the Handcart

"Many people have asked us why we didn’t build a four-wheeled cart that wouldn’t need to be balanced. However, four wheels would double the rolling resistance and thus the effort required to push the cart. Furthermore, a four-wheeled cart is less maneuverable and more difficult to drive on uneven terrain. You also need to get two extra wheels, and you need to build a steering mechanism. "

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'll see your handcart and raise you one yatai.

https://youtu.be/FEgTg_IyHwQ

The lowtech magazine raised you already with a link to their previous article on the one-wheeled Chinese wheelbarrow - https://solar.lowtechmagazine.com/2011/12/how-to-downsize-a-... . ;)

HN comments at https://news.ycombinator.com/item?id=17792329 and https://news.ycombinator.com/item?id=4285086 .

> four wheels would double the rolling resistance and thus the effort required to push the cart

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."

Given that it appears to be made (at least all the mechanical bits) out of bike parts, I kind of wonder why they didn't just make a cargo bike.

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.