Freight Tricycle

Overview

The freight tricycle is a heavy pedal vehicle built to move bulky loads short distances at low speed. It uses one steered wheel at the front and two driven wheels at the rear, set behind and below a large steel cargo bed. A rider sits over the front of the frame, pedals a crank, and drives the rear axle through a chain. With 200-300 kg in the bed the trike cruises at 8-15 km/h, which suits market delivery, waste collection, vending, and last-mile freight in dense towns where a van cannot fit or park.

Unlike a child's tricycle, every load path on a freight trike is sized for cargo. The frame is mild steel tube rather than thin alloy, the wheels carry 40 spokes rather than 32, and the rear axle uses a differential so the machine can turn under load without scrubbing a tyre. The result is a kerb weight of 55-75 kg, several times that of a road bicycle.

Frame and chassis

The backbone is a welded steel tube ladder of 38 mm outside diameter, 2.5 mm wall, gusseted where the bottom bracket shell meets the down tube. At the front a Head Tube holds the headset bearings at a 72 degree angle and a 45 mm rake, geometry chosen for stable steering at walking pace rather than quick handling. A rigid front fork of brazed steel blades carries the single front wheel.

Behind the rider the frame opens into a box-section rear subframe. Two load rails of 50 by 30 by 3 mm steel run fore and aft, tied by an axle cross member that carries the pillow bearings. Four bed mounts with rubber pads locate the cargo box and isolate it from road shock. A Fastener Set of grade 8.8 bolts joins the removable parts.

Pedal drivetrain

Power starts at the crankset, a 170 mm steel pair turning a stamped 46 tooth chainring on a sealed square-taper cartridge bottom bracket. A 1/2 by 1/8 in primary chain runs back to a Jackshaft, an intermediate shaft on two pillow blocks and sealed bearings. The jackshaft carries a pair of sprockets that multiply the gearing by about 1.8, which lowers the ratio enough to climb a grade with a full bed. A second chain then drives the rear axle. A screw-on freewheel lets the trike coast downhill without back-driving the pedals.

Rear axle and differential

The two rear wheels sit on a live axle assembly. Rather than locking both wheels to one shaft, which would fight every corner, the trike uses a compact bevel Bevel Differential in a cast iron carrier. The carrier turns on bearings sealed by seals, and a bolt-on 36 tooth sprocket takes the chain drive. Two splined half shafts run inside a steel axle tube out to the wheels, supported by four pillow bearings. Each rear wheel carries a reinforced 6 ply cargo tyre rated 150 kg.

Steering and braking

Steering is direct. A swept Swept Handlebar on a quill Quill Stem turns the steerer in the threaded headset, moving only the front wheel. Because only the light front end steers, the bar is wide for leverage at low speed.

Stopping a loaded trike needs more than a bicycle caliper. Each rear hub carries a 90 mm internal-expanding drum brake with bonded shoes and return springs, which resist fade far better than rim brakes when the bed is full. The front wheel keeps a lighter rim caliper. Three Bowden cables run from the hand levers, and a ratcheting parking lock holds a rear drum applied so the trike stays put on grades up to 8 percent during loading.

Cargo bed and materials

The cargo bed is the point of the machine. A welded angle-iron frame of 40 by 40 by 4 mm steel carries an 18 mm marine plywood floor and four hinged drop sides on hinges and latches, so all sides fold flat for loading pallets or sacks. Front and floor steel panels close the box. Flatbed and insulated-box variants share the same subframe.

Materials are chosen for repair in the field: mild steel tube, plain plywood, and standard chain. A rider can patch a tyre, replace a chain, or reline a drum with simple tools. That serviceability, plus the low running cost of muscle power, keeps the freight tricycle in daily use across Asia, Africa, and European cargo schemes.