Port & airport tyres

Reach stackers and loaded container handlers put more load through a single tyre than almost any other wheeled machine. The load is high, the speed is low, the turning is tight and often done stationary, and the machine is asked to lift at reach, which transfers weight onto the front pair far beyond the static axle figure.

Specify a port pattern rather than a loader pattern. The casing is built for heat and for the sidewall loading that comes from articulating under load, and the tread is a deep, dense block designed to resist cutting on concrete rather than to find traction in loose material. A quarry L-5 looks similar and does not behave the same on a container terminal.

Front and rear are different fitments on most of these machines. The front pair does the lifting and the rear pair steers, so the wear pattern, the pressure and often the ply rating differ between the two. Order for the position, not for the machine.

A straddle carrier runs eight or more wheels, spends its whole life on concrete, and travels further in a shift than a reach stacker does in a week. Continuous running at moderate speed with a container overhead makes heat the governing factor, and the tyres are usually the pacing item on the machine’s maintenance schedule.

Because the load is spread across many wheels, the individual tyre load is lower than on a handler, but the duty is far more sustained. That shifts the specification towards the work rating — the load and speed the tyre can sustain over a shift — rather than the peak load.

Position matters on a straddle. Wheels on the inside of the standard turning direction do most of the scrubbing, so a rotation policy pays for itself. Review rotation intervals against wear patterns and the equipment manufacturer’s guidance.

Terminal tractors — shunters, tugs, yard horses — do continuous short runs at or near full trailer weight, with constant tight turning and a fifth wheel that loads the rear axle heavily. Highway truck tyres fitted to a shunter fail from heat and shoulder wear, not from mileage, because they were designed for a duty cycle that includes cooling.

The 18-19.5 industrial fitment is the traditional answer and remains the right one for most yard tractors: a heavy bias casing, a deep block tread and a sidewall built for kerbing. Where a tractor also runs on the public road between terminals, a 385/65R22.5 or a 12.00-20 becomes the practical compromise, with the road legality and speed rating that requires.

These tyres die from sidewall damage as often as from tread wear. Kerbs, trailer legs and quayside furniture do the damage, so a kerbing rib and a reinforced sidewall are worth more than an extra millimetre of tread.

Rubber-tyred gantries carry enormous static loads on many wheels and move slowly and intermittently along a stack. The tyre spends much of its life stationary under load, which produces flat-spotting and casing set, then is asked to travel and steer at right angles during a gantry move.

The load per wheel is the number that governs the fitment, and it is not evenly distributed — corner loads differ across the machine and change as the trolley traverses. Specify against the crane manufacturer’s wheel load figures rather than dividing the machine weight by the number of wheels.

Because these tyres do low mileage in a long life, ageing and ozone damage matter as much as wear. A yard crane tyre with plenty of tread and eight years of sidewall cracking is finished.

Ground support equipment covers a wide spread of machines — belt loaders, catering and cargo high loaders, water and lavatory trucks, tugs and steps — most of which do very low mileage in short, heavily loaded bursts, close to aircraft.

Two things separate airside from every other yard. The first is that the equipment stands still for long periods and then works hard, which is exactly the pattern that produces flat spots and under-inflation failures. The second is foreign object damage discipline: anything a tyre picks up or sheds is a hazard to aircraft, so tread condition is inspected for what it might throw as much as for what it has left.

Solid and foam-filled options are common on GSE for the simple reason that a puncture on a stand is an operational incident rather than an inconvenience. The trade-off is ride quality and shock loading through the machine, which matters on equipment that docks against an aircraft.

Dollies and baggage carts are towed in trains, take heavy point loads, and are routinely dragged sideways in tight ramp manoeuvres. Include pressure and condition checks in their routine maintenance schedule.

The metric industrial sizes — 250-15, 300-15 — are the mainstream fitments and are available as pneumatic, solid resilient and foam-filled. On a large ramp fleet the maintenance argument for solids is strong: no pressure checks, no punctures, no dollies parked out of service waiting for a wheel.

Where pneumatics stay, run a fixed inspection interval rather than relying on a driver noticing. An under-inflated dolly tyre destroys its own sidewall in a few days of ramp work.

Pushback and towbarless tractors are heavy, low-geared machines that apply very high tractive effort at almost no speed, often on a wet or contaminated stand. Traction and casing strength govern the fitment, and the machine’s own ballast means the static load is high before anything is attached to it.

These tyres wear their shoulders through scrub during turns and lose tread quickly under high torque, but the failure that matters is a cut or a burst on the stand. Casing strength, ply rating and inspection frequency are the things to specify for, not tread life.

Airside operators generally set a fixed replacement interval and a defined damage threshold for these machines, and take the tyre out at that point regardless of remaining depth. Follow the operator’s documented inspection and replacement policy.

Terminal trailers, roll trailers and quayside running gear take high static loads, spend their lives being pushed and dragged around tight corners, and need regular condition checks. Tyre failure here usually starts as sidewall damage from a dock leveller, a kerb or a trailer leg.

Specify for scrub and impact rather than for mileage: a reinforced sidewall, a kerbing rib and a bead area that will survive repeated docking. Choose tread depth for the specified trailer duty.

Where trailers sit loaded for weeks, check pressures before they move. Flat-spotted, under-inflated trailer tyres that are then dragged across a yard fail at the bead, and a trailer stranded in a lane costs more than the tyre several times over.