What Is a Cantilever Gate? How It Works, Sizes and When to Specify One
- A cantilever gate is a slide gate that hangs from rollers on posts beside the opening, so nothing touches the ground inside the opening.
- A counterbalance tail, roughly half the width of the opening, keeps the gate level as it rolls across.
- Compared with a V track gate, it has no ground track to fill with debris, snow or ice, but it needs more run back space and stronger posts.
- ASTM F1184 covers cantilever slide gates, ASTM F2200 and UL 325 apply when the gate is automated, and ASTM F2656 applies when the gate must stop a vehicle.
A cantilever gate is a slide gate that spans an opening with no support inside it. The gate hangs from rollers mounted on posts beside the opening and rolls parallel to the fence, with a counterbalance tail behind the posts holding it level. This guide explains how a cantilever gate works, how it compares with V track and swing gates, which ASTM standards apply and how to specify one for a secure site.
What Is a Cantilever Gate?
A cantilever gate is a horizontal slide gate that crosses the opening without touching the ground. ASTM F1184, the standard specification for industrial and commercial horizontal slide gates, classifies it as a Type II gate: a cantilever slide gate spanning an opening with no top or bottom support within that opening.
Because there is no wheel or track in the opening, vehicles cross a clear driveway, and the gate keeps working when the ground is uneven, muddy, snowy or covered in debris. That is why cantilever gates are common at commercial, industrial and high security entrances.
How Does a Cantilever Gate Work?
A cantilever gate rolls on sets of rollers fixed to two or more posts beside the opening. Steel gates usually run between rollers at the top and bottom of the frame, while aluminum gates often ride on trucks inside a track built into the frame.
The gate is longer than the opening it closes. The extra length, called the counterbalance or tail, sits behind the support posts and balances the part of the gate that reaches across the opening. The tail is typically about half the width of the opening. When the gate opens, the whole panel slides back along the fence line, so the site needs clear run back space for the gate and its tail.
What Is the Difference Between a Cantilever Gate, a V Track Gate and a Swing Gate?
The main difference is where the gate is supported. A cantilever gate hangs from posts, a V track gate rolls on wheels along a track set in the ground, and a swing gate pivots on hinges.
| Cantilever gate | V track gate | Swing gate | |
|---|---|---|---|
| Support | Rollers on posts beside the opening | Wheels on a ground track across the opening | Hinges on a gate post |
| Ground contact in the opening | None | Track across the full opening | None, but needs a clear swing arc |
| Debris, snow and ice | Not affected | Track must be kept clear | Swing path must be kept clear |
| Space needed | Run back space for the gate plus its tail | Run back space for the gate only | Swing arc in front of or behind the opening |
| Uneven or sloped ground | Handles it well | Track needs level ground | Limited by the slope in the swing path |
| Automation | One operator, straight travel | One operator, straight travel | Often two operators for a double gate |
For more on gate types, see our comparison of sliding gates and bi folding gates and our overview of security gates for business. For gates that fold instead of sliding, see our guide to bi folding gates.
What Are the Disadvantages of a Cantilever Gate?
The main disadvantages of a cantilever gate are the space it needs and the structure it takes to carry its weight. Plan for them early, because they set the site layout.
- Run back space: the gate and its tail slide alongside the fence, so the fence line beside the opening must stay clear for roughly one and a half times the opening width.
- Heavier posts and foundations: the posts carry the whole gate as a lever, so large or tall gates need stronger posts and deeper foundations, designed by the project engineer.
- More material: the tail adds length and weight that a V track gate does not need.
- Careful fabrication: the frame needs bracing so a long gate does not sag over time.
How Wide Can a Cantilever Gate Be?
A single cantilever gate commonly closes openings up to about 30 ft, and a pair of cantilever gates meeting in the middle can close about 60 ft. Heavier frame designs go further, but every extra foot adds tail length, weight and post load.
For very wide entrances, a pair of gates is often easier to fit than one long gate, because each gate needs only half the run back space.
What Standards Apply to Cantilever Gates?
Three ASTM standards and one UL standard cover cantilever gates, depending on whether the gate is manual, automated or crash rated.
| Standard | What it covers | When it applies |
|---|---|---|
| ASTM F1184 | Industrial and commercial horizontal slide gates, including Type II cantilever slide gates | Every cantilever gate specification |
| ASTM F2200 | Construction of automated vehicular gates, including horizontal slide gates | When the gate will have an operator |
| UL 325 | Safety of gate operators | With ASTM F2200 on every automated gate |
| ASTM F2656/F2656M | Full scale crash testing of vehicle security barriers | When the gate must stop a vehicle |
ASTM F2200 requires automated vehicular gate systems to comply with UL 325 as well, so the two are specified together.
Can a Cantilever Gate Be Crash Rated?
A cantilever gate can be crash rated only if the complete gate, with its posts and foundations, has passed a full scale crash test. A standard cantilever gate built to ASTM F1184 controls access but carries no vehicle stopping rating.
Crash rated gates are tested under ASTM F2656/F2656M, which rates them by the test vehicle, the impact speed and the penetration. M50 P1, for example, means a 15,000 lb truck at 50 mph that traveled 1 m (3.3 ft) or less past the gate. The rating belongs to the tested configuration, so ask for the crash test certification that covers the gate being supplied. For the full rating system, see ASTM F2656 crash ratings explained.
A cantilever version and a tracked version of a slide gate are two different configurations. A rating earned by one does not carry over to the other, so check which version the certification covers.
BSP’s anti ram crash gates show the difference. The AVBD 250 slide gate is crash tested to the 2023 edition of ASTM F2656 at M50 P1 in a tracked configuration, with the gate running on a track across the opening, and its rating covers only that tracked version. For openings where a ground track is not wanted, BSP also builds the AVBD 230 cantilever slide gate.
How Do You Specify a Cantilever Gate?
Specify a cantilever gate by its opening, its standard and how it will be used. Six points cover most specifications:
- Opening and run back space: state the clear opening width and confirm the fence line beside it can take the gate and its tail.
- Gate type and class: name ASTM F1184 Type II, with the roller class the design uses.
- Automation: if the gate will have an operator, require ASTM F2200 construction and a UL 325 listed operator.
- Vehicle threat: if the gate must stop a vehicle, name the ASTM F2656 rating and require the crash test certification for the configuration supplied.
- Posts and foundations: have the project engineer design them for the gate size and site soil.
- Fence line tie in: match the gate to the fence system, such as SecureMesh welded mesh or SecurePale palisade, so the opening is not the weak point.
See BSP’s security fencing and active vehicle barriers for the systems a gate ties into.
Cantilever Gate FAQs
What is a cantilever gate?
A cantilever gate is a slide gate that hangs from rollers on posts beside the opening, with a counterbalance tail behind the posts. Nothing touches the ground inside the opening.
Does a cantilever gate need a track?
No. A cantilever gate rolls on rollers mounted to posts beside the opening, so there is no ground track or wheel in the driveway.
How much space does a cantilever gate need?
It needs clear run back space along the fence line for the gate plus its counterbalance tail. The tail is typically about half the opening width, so plan for roughly one and a half times the opening.
What is the difference between a cantilever gate and a V track gate?
A cantilever gate hangs from posts and never touches the ground in the opening. A V track gate rolls on wheels along a track across the opening, which must be kept level and clear of debris, snow and ice.
Can a cantilever gate be crash rated?
Yes, if the complete gate with its posts and foundations has passed a full scale crash test under ASTM F2656 in the cantilever configuration. A rating earned by a tracked version of the same gate does not carry over, so ask for the crash test certification for the configuration being supplied.
Need a Gate That Matches Your Fence Line?
Send us the opening width, the run back space and whether the gate must stop a vehicle, and we will recommend a gate and fence configuration and supply the submittal package.
The BSP Specifier Brief
Spec language, standards and new CAD, in your inbox
For the architects, engineers and federal facility teams who write perimeter security specs.