Hamilton built the Enhanced Maxi-Duty EMD2 to solve a specific problem at the top of the capacity range: how to carry up to 40,000 lb per caster without the deck climbing out of reach. The answer is dual-wheel construction — two wheels per caster spread the load across two contact patches, which keeps the wheel diameter (and therefore the overall height) low while the rating stays extreme.
A single-wheel caster rated for 40,000 lb needs an enormous wheel — 16 to 22 inches in diameter — to keep the contact-patch psi within range. That raises the deck two feet or more off the floor, which changes how the equipment is built, where it can travel, and what clears overhead. The EMD2's dual-wheel design splits the 40,000 lb load across two wheels and two bearing assemblies. Each wheel carries half the load, so each can be smaller, so the whole caster — and the deck above it — rides low.
Dual-wheel construction also buys stability the single-wheel design can't. Two parallel contact patches resist the twisting force generated when a heavy platform corners or takes a side load. A single wide wheel under the same force can bind the swivel; the EMD2's two wheels brace against each other through the spacing between them.
Hamilton's own description of the EMD2 line is blunt about the design priority: maximum capacity at minimum height. The EMD2 carries up to 40,000 lb per caster while keeping the overall height far below what an equivalent single-wheel caster would require. That matters for the applications it serves — aerospace fixtures that roll under overhead manipulators, machine tools that slide beneath low cranes, transfer platforms in facilities with fixed overhead clearance. The capacity is the headline; the low profile is the reason you'd choose EMD2 over a tall single-wheel build at the same rating.
Choose the EMD2 when you need extreme capacity and the height envelope is a real constraint — aerospace tooling, low-clearance machine transfer, fixed-overhead facilities. Choose Hamilton's single-wheel Ultra Maxi-Duty instead when you have the vertical clearance and want the simplicity of a single wheel. Step down to the Maxi-Duty MD series if your load per caster is at or below 23,000 lb — you'd be paying for EMD2 capacity you don't need.
