The Run a Slide Gate Needs
Pace It Before Anything Else
The first question about a sliding gate is not which type or what it costs. It is whether the space exists. Stand at the gate post, walk along the fence line in the direction the gate will open, and count the distance. If it runs out before the required length, the conversation is over and the entrance needs a different mechanism.
The Numbers to Expect
A track gate needs a clear run at least as long as the opening, plus a little for the end stop. A cantilever needs meaningfully more, because the counterbalance tail extends behind the support posts even when the gate is closed. The rule of thumb is around one and a half times the opening width in total, and the extra is exactly the part people forget to measure.
Obstructions Above and Below
The run has to be clear at the height of the leaf, not just at ground level. A tree with low branches, a utility box, an air conditioning unit, a mailbox, a stack of stored material that has been there so long it reads as permanent. Any of these occupies the space the gate needs. Below ground matters too on a cantilever, because the support posts need deep footings and cannot land on a buried service.
Level Along the Run
The ground the gate retracts over does not carry any weight on a cantilever, but on a track design the rail must be straight and at a consistent level for the whole travel. A run that falls away, or that crosses a path at a different height, means either regrading or accepting a rail that is not level, and a wheel running downhill into a gate that then has to be pushed back up is not a small annoyance.
The Neighbour Question
The retraction run frequently sits along a boundary, and a cantilever tail can overhang. Where the fence line is shared, it is worth confirming the position of the boundary properly rather than assuming the fence marks it. Establishing that before the posts go in is far easier than establishing it afterwards.
If the Run Is Not There
The usual alternatives are a bi parting swing pair, which halves the arc each leaf sweeps, or a bi parting slide where two shorter leaves retract in opposite directions and each needs only half the run. The second doubles the hardware and is genuinely useful on a wide opening with limited space either side. Neither is a compromise on quality, and both are better outcomes than forcing a single slide into a space that cannot take it.