01
Wheels, bearings and the mechanical advantage
The wheel does one thing: it replaces sliding friction with rolling friction, and the difference is enormous.
But a wheel is only as good as its bearing, and the bearing is where the losses and the wear actually are. Historical solutions were a hardwood or metal bush on a fixed axle, greased, and designed to be replaced when worn rather than to last forever. That replaceability is the design principle worth carrying over.
Wheel diameter matters more than it looks. A large wheel rolls over obstacles and soft ground far better than a small one, because the angle it has to climb is shallower. That's why farm carts had big wheels and why a barrow with a small hard wheel is miserable on rough ground.
Tyre width is the soft ground answer. Narrow wheels concentrate load and sink; wide ones float. Traditional vehicles for soft ground had broad tyres for exactly that reason, and it's still the right principle.
And keep the load low and over the axle. A high load makes a vehicle unstable, and a load badly placed relative to the axle either makes it hard to lift or hard to control.
02
Barrows, carts and what you can build
Simple wheeled vehicles are within reach of an ordinary workshop and they multiply what one person can do.
A wheelbarrow places the load between the wheel and the operator, so the wheel carries most of it. Where the load sits along that span decides how much you're lifting, and moving it forward towards the wheel makes a barrow dramatically easier. Most badly designed barrows have the load too far back.
A two-wheeled cart carries its load entirely on the axle and needs only guiding, which is why it's the workhorse of small-scale transport everywhere. It can be pulled by a person, an animal or a machine, and it can be built from timber with a bought or salvaged axle.
Four-wheeled wagons carry more and need a steering arrangement, traditionally a turning front axle. They're more capable and considerably more to build.
Sledges have no wheels at all and work well on snow, on wet grass and on soft ground where wheels sink. They're the simplest thing to make and they're frequently the right answer in conditions where a cart is not.
03
Animal draught
An animal converts feed you can grow into hauling power, which makes it the transport equivalent of a self-fuelling engine.
The harness is where the knowledge sits. A collar transfers load through the shoulders and is what allows heavy draught; a breastcollar sits across the chest, is lighter and simpler and suits lighter loads. Both must fit the individual animal, because a badly fitted collar causes sores that put an animal out of work for weeks and does its damage invisibly first.
Load is not just weight. Gradient, surface, rolling resistance and duration all change what's reasonable, and a load that's fine on firm level ground is not fine in mud or on a slope. Animals will try beyond what's good for them, so the judgement is entirely the handler's.
Oxen and horses differ in character as much as in power: oxen are slower, steadier, stronger for sustained pulling and cheaper to keep; horses are faster and more responsive. Which suits depends on the work and the ground.
Route matters more with animals than with machines. Gradients that a vehicle shrugs off cost an animal real effort, and traditional tracks are graded gently for that reason instead of taking the direct line.
04
Water transport
Where water is available it's the most efficient transport there has ever been, and it isn't close.
A given effort moves far more on water than on land, because the vessel is supported, not dragged and because there's no gradient. One person can move a load by boat that would need an animal and a cart overland, which is why every early trade network followed rivers and coasts.
Small craft are genuinely buildable. Flat-bottomed punts and dories, and skin or canvas over frame, are all within reach of ordinary woodwork, and they're the traditional working boats of shallow water everywhere.
Loading and stability are the practical skills. A boat is stable up to a point and then very suddenly is not, load has to be kept low and distributed, and freeboard, the height from waterline to gunwale, is the margin that keeps water out.
Water is unforgiving in a way roads aren't. Cold water incapacitates fast, and the sensible practice, buoyancy aids, telling someone the plan, not overloading, and respecting weather, is not optional.
05
Keeping vehicles running
Whatever the vehicle, the failure points are consistent and mostly preventable.
Bearings and axles wear and need lubrication and eventual replacement, and this is where most traditional vehicles were designed for easy renewal instead of for long life.
Wheels loosen. A traditional wooden wheel is held in compression by its iron tyre, and if that slackens, usually because the timber has dried and shrunk, the wheel comes apart. Keeping wooden wheels from drying out is a real maintenance task, which is why they were sometimes stood in water.
Loads cause most damage. Overloading breaks axles, cracks frames and destroys wheels, and it does it gradually so the failure appears unrelated to the cause.
And for anything motorised, the honest question is the fuel and the parts. A vehicle whose fuel can't be obtained is a shed. That's an argument for keeping something simpler in reserve and not for not having a vehicle.
06
Routes, and the surface you travel on
Transport is only as good as what it travels on, and a route is infrastructure that has to be maintained.
Gradient is the constraint that matters most for anything animal-drawn or human-powered, which is why old tracks wind, not climb directly. The extra distance costs less than the extra effort.
Surface decides whether a route works in the wet, and that comes back to drainage: shedding water sideways, ditches to carry it, and cross-drains before it gains enough speed to cut. A route that fails in wet weather is a route that fails when it's most needed.
Fords, crossings and gates are the pinch points, and they're where routes actually become impassable. They're worth more attention than the length between them.
Think about the network in place of the single route. One way in and out is a single point of failure, and knowing a second way, even a slow one on foot, is the difference between inconvenience and isolation.