Car lift terms explained

Configurations

Two-post lift

A two-post lift raises a vehicle by its frame or pinch welds on swing arms between two columns, leaving all four wheels hanging free.

The configuration for brake, suspension and exhaust work. Needs anchoring into the slab and the most ceiling height.

Four-post lift

A four-post lift is a drive-on runway supported at four corners, with the vehicle's wheels remaining loaded on the platforms.

Free-standing in most configurations, so no anchors. The usual answer for storage and for stacking two cars.

Scissor lift

A scissor lift raises a vehicle on a folding frame beneath it, with no columns at either side.

Small footprint, no door obstruction, least overhead room needed. Central underbody access is limited.

Clear-floor lift

A clear-floor two-post lift runs its equalisation cables through an overhead assembly, leaving the floor between the columns unobstructed.

Nothing to drive over or trip on, at the cost of needing more ceiling height than a floor-plate design.

Floor-plate lift

A floor-plate two-post lift runs its equalisation cables through a channel across the floor rather than overhead.

Buys back roughly a foot of ceiling height. You drive over the plate and it is a trip hazard.

Asymmetric lift

An asymmetric two-post lift has rotated columns and shorter front arms, positioning the vehicle further back so its doors clear the posts.

The configuration to choose if people get in and out of the car while it is on the lift.

Symmetric lift

A symmetric two-post lift centres the vehicle between the columns on equal-length arms.

Loads the columns evenly, which suits trucks and vans. Door clearance is worse than asymmetric.

Components

Power unit

The power unit is the motor and hydraulic pump assembly that drives the lift's cylinders.

Its voltage decides your electrical work. 208-230V single phase is a dedicated circuit, not a garage outlet.

Equalisation cable

Equalisation cables synchronise the two carriages of a two-post lift so they rise and fall together.

They do not hold the vehicle up. They stretch over time and need adjusting when the carriages drift out of level.

Lock ladder

The lock ladder is the toothed rail inside each column into which the mechanical safety locks engage at fixed heights.

Raise until the locks engage audibly, then lower onto them before going underneath. Every time.

Lock release

The lock release is the lever or handle that disengages the safety locks so the lift can be lowered.

On a two-post it must release both columns together. A single-point release is the common arrangement.

Bridge jack

A bridge jack is a hydraulic or air jack that spans a four-post lift's runways to raise the wheels clear of the platforms.

Without one, a four-post cannot do wheels-off work. Budget for it at the same time as the lift.

Pinch weld puck

A pinch weld puck is a rubber pad shaped to sit on a unibody vehicle's reinforced seam without crushing it.

Using the wrong pad on a unibody car bends the sill. Most lifts ship with a basic set.

Drive-thru clearance

Drive-thru clearance is the width between a two-post lift's columns at their narrowest point.

This is the number that decides whether a wide vehicle can get in between the posts at all.

Requirements

Overall height

Overall height is the height of the lift structure itself, measured from the floor to its highest point.

It is not the ceiling height you need. You need clearance above it, and above the raised vehicle.

Anchor embedment

Anchor embedment is the depth an anchor bolt must be set into concrete to reach its rated holding capacity.

Stated in the installation manual. An anchor that spins rather than tightening has not set, and torquing harder makes it worse.

Compressive strength

Compressive strength, quoted in psi, is the load concrete can carry before it fails, and it is stated as a minimum for every anchored lift.

Thickness alone is not enough. A thick, weak slab can still fail under anchor loads.

Single phase

Single phase is a domestic and light-commercial electrical supply, as opposed to the three-phase supply found in industrial buildings.

Most home-garage lifts are single phase. Whether it is 110V or 230V decides whether you need an electrician.

Standards and paperwork

ALI certification

ALI certification is third-party testing of a specific lift model against the ANSI/ALI ALCTV standard, with ongoing audit of production.

It attaches to a model at a capacity, not to a manufacturer. Check the ALI directory for the exact model.

ANSI/ALI ALOIM

ANSI/ALI ALOIM is the American standard covering the operation, inspection and maintenance of automotive lifts.

It is the basis for the annual inspection your insurer is likely to ask about in a commercial setting.

Freight class

Freight class is the NMFC category that determines what an LTL carrier charges to move a shipment.

A lift's crated weight and dimensions set its class, and its class sets a large part of your delivery cost.

Liftgate delivery

Liftgate delivery is an LTL service where the truck carries a powered platform to lower a pallet to ground level.

Without a dock or forklift you need one, and at a residential address that is almost always the case.