Most people researching an automatic swing gate are picturing the finished result the elegant hinged opening, the classic kerb appeal. Fair enough. But the decision that actually determines whether your gate works reliably for the next fifteen years isn’t the leaf design or the finish. It’s the motor mechanism hidden underneath, and there are three genuinely different types that aren’t interchangeable. Pick the wrong one for your pillars, your gate weight, or your budget, and you end up with a gate that strains, sticks, or needs replacing far sooner than it should. We’re East London Metal Engineering, and this is the conversation we have with almost every swing gate client before a single piece of steel gets cut.

Ram Motors: The Default for Good Reason

A ram (or linear) motor is a long, thin arm that extends to push the gate open and retracts to pull it closed, usually powered by either a hydraulic piston or a threaded screw mechanism. It mounts to the gate post at one end and the gate itself at the other.

This is the motor type most people end up with, and there’s a reason for that: it’s the most cost-effective option, it’s straightforward to install, and it’s the go-to choice when you’re automating a gate that’s already there rather than building new. The tradeoff is that it needs a reasonable amount of depth on the pillar to mount properly, and most ram setups only open inward which is fine for the vast majority of driveways, but worth knowing before you commit to a design that assumes otherwise.

Articulated Arm Motors: The Answer to Awkward Pillars

An articulated arm motor works differently instead of one straight arm, it uses a hinged, two-part arm that folds and unfolds like an elbow. This gives it the ability to reach around obstacles a straight ram simply can’t clear.

This is the motor we reach for when a property has wide or oddly-positioned brick pillars, or when the gate hinges sit further forward on the post than a ram’s geometry allows. It’s also generally a touch faster in operation than a ram. The tradeoff is more moving parts, which means slightly more to think about at annual service time, and the arm itself is a bit more visible than a well-fitted ram.

Underground Motors: Invisible, but Only If You Plan for It Early

An underground motor sits inside a sealed housing buried in the ground near the hinge point, with the gate pivoting on a pin that protrudes from the box. From outside, all you see is the gate moving no visible arm, no motor casing.

This is the motor of choice when appearance matters more than anything else, which is common on period properties and conservation-area frontages where a visible mechanism would clash with the setting. The catch is that it needs real groundwork: a foundation box, proper drainage so it doesn’t flood, and enough excavation depth to house it. This is also why underground motors are a poor fit for retrofitting onto an existing gate and pillar setup they’re much better suited to a new gate designed around the motor from the start, rather than squeezed in afterward.

The Clearance Problem Nobody Budgets For

Here’s something that trips up more projects than motor choice itself: swing gates need somewhere to actually swing to. The full length of the gate leaf has to sweep through open air, and on a lot of properties that arc runs straight into a parked car, a wheelie bin store, a garden wall, or if the gate opens outward the pavement itself.

Before settling on a swing gate at all, it’s worth physically measuring the clear arc your leaf will need, not just eyeballing it. If a single leaf can’t clear that arc without hitting something, the fix is usually one of two things: split it into a double-leaf gate with two shorter arms swinging through a smaller radius each, or reconsider whether a sliding gate suits the site better. Either way, this is exactly the kind of thing a proper site survey catches before fabrication starts, rather than on installation day.

Single Leaf vs Double Leaf: Why It Changes the Motor Question Too

A single-leaf gate spanning a wide entrance means one long, heavy leaf for the motor to move which pushes you toward a stronger ram or an articulated arm rather than a lighter-duty setup. Split the same opening into a double-leaf gate and each leaf is roughly half the length and weight, which is easier on almost any motor type and often the more practical choice on wider driveways for exactly that reason. It’s also worth knowing this before falling in love with a single sweeping gate design that a smaller motor simply won’t be rated to move reliably over time.

Two Real Scenarios That Show the Difference

A fairly typical call: a Victorian terrace with a narrow entrance flanked by wide, decorative brick pillars. A standard ram needed more depth on the pillar face than was available without cutting into the brickwork, so an articulated arm motor which folds rather than needing that straight-line depth was the better fit without touching the existing masonry.

Compare that to a converted warehouse unit with a reinforced concrete apron and a brief that specifically called for no visible mechanism at all, for a cleaner architectural look. That’s a textbook underground motor scenario but because it was factored in from the design stage rather than added afterward, the groundwork and drainage could be planned properly instead of retrofitted around an existing gate.

What We’d Default to If You Asked Us Cold

For a fairly standard UK residential driveway with solid pillars and enough depth to work with, a ram motor remains the sensible starting point it’s reliable, cost-effective, and the easiest to service down the line. We’d move to an articulated arm if the pillar geometry doesn’t suit a ram, and we’d only recommend underground if invisibility is a genuine priority and you’re building the gate fresh rather than automating an existing one. None of these is objectively “best” they solve different problems, and the right one depends entirely on what your pillars and budget will actually allow.

Quick Answers

Can a ram motor be fitted to a gate that opens outward?

It’s possible on some setups, but the geometry is more awkward and most ram installations are optimised for inward opening worth flagging early if outward opening is a hard requirement for your site.

What if my pillars are too narrow for an articulated arm?

Narrow pillars can also rule out an articulated arm’s swing radius, in which case a ram which needs depth rather than width often becomes the more workable option, or the pillars themselves may need minor rebuilding.

Can I switch motor types later without rebuilding the gate?

Sometimes, but not always underground motors in particular are difficult to add after the fact, so it’s far better to settle on the mechanism before the gate is fabricated rather than after.

If you’re weighing up a swing gate and aren’t sure which mechanism actually suits your pillars and driveway, that’s exactly what a site survey is for. East London Metal Engineering designs and fabricates the gate around the motor that fits your property, not the other way round. Get a quote or call 079 5167 3924.