A four-post lift is great for driving on and driving off, but the moment you want to lift a wheel free of the runway you need somewhere for a jack to sit. That is what a lift jack tray is: the bolt-on shelf or rolling bridge that spans between the runways of a four-post lift and holds an air, air-hydraulic, or bottle jack. This guide covers the two main styles — bolt-on trays and bridge jack rails — how they compare, and what fits BendPak, Rotary, Challenger, and Forward four-post lifts.
What a lift jack tray does
A four-post lift raises a vehicle on its tires; nothing is lifting the suspension. To swap brakes, rotate tires, or drop a diff you need to raise one axle or one wheel off the runway. A lift jack tray gives you a stable, load-rated platform between the two runways to sit a jack on. Trays either bolt permanently across the runways at fixed points, or ride on rails so a bridge jack can roll to any position along the length of the lift. Both approaches turn a storage-and-inspection lift into a real service lift, and both have honest tradeoffs.
Bolt-on jack trays: the simple option
A bolt-on lift jack tray is a steel platform that clamps or bolts to the inner edge of both runways at a chosen position. It stays where you put it, it does not need rails, and it is the least expensive way to add jacking to a four-post lift you already own. Trade-off: the tray covers one fixed section of the runway, so if the vehicle’s jacking point doesn’t line up with the tray you have to reposition the tray or reposition the vehicle. Most trays are rated for a bottle jack or a low-profile floor jack; add-on air-over-hydraulic units are common. Bolt-on trays are the right choice for home garages and light-duty shops that jack one section of vehicles consistently.
Bridge jack rails: the shop-grade option
Bridge jack rails run the full length of the runways and let a purpose-built rolling jack — a bridge jack — slide anywhere between the columns. The jack itself is a low-profile air-hydraulic unit with two extending saddles that reach out under a frame or subframe. Rails let you jack any point on any wheelbase from a subcompact to a service truck, and a proper shop-grade bridge jack lifts several thousand pounds, easily enough for a full front or rear axle. Rail installation usually involves bolting rail sections to the inner face of each runway; on some lifts the rails ship as an option and on others they are a factory-installed part of the runway assembly.
BendPak 4-post jack trays and jacks
BendPak sells rolling bridge jacks (RBJ series) sized to their HD-series four-post lifts, and they offer bolt-on tray options for HDS lifts and home-storage HD-9 units. The rolling jacks require the correct rail spacing, so a jack sized for an HD-9 will not fit an HDS-27 without spacers. If you are adding a jack to a BendPak lift, match to the exact model number; our team can confirm before you order. See our other lift parts hub for BendPak-compatible accessories, or run the model through parts lookup.
Rotary 4-post jack trays and rolling jacks
Rotary four-post lifts (SM14, SM18, SM122, SM144, ARO14, ARO18) support rolling jacks — Rotary sells them as RJ or J-series bridge jacks — and bolt-on tray options for storage models. Rotary rolling jacks are air-hydraulic, capacity-matched to the runway rating, and use Rotary-specific rail geometry. If your Rotary four-post did not ship with jack rails, retrofitting them is possible on some models and not on others; call before ordering. Rotary-branded and cross-compatible parts are in our Rotary aftermarket parts hub.
Challenger and Forward 4-post options
Challenger four-post lifts (4015, 4018, 4030, 44000, 40000, 44030) offer factory-matched rolling jacks and bolt-on jack trays. Challenger rolling jacks share design DNA with Rotary and Forward jacks — they come from a common industry supplier — but the mounting hardware and rail interface is Challenger-specific. Forward four-post lifts have the same story: matched rolling jacks and optional trays with Forward-branded fitment. The honest fact across all four brands is that a rolling jack is a factory or dealer accessory, and while an aftermarket “universal” jack may look right, verify rail width, saddle extension, and capacity before you buy.
Retrofit installation and jack capacity
Retrofitting a tray or a set of bridge jack rails onto an existing four-post lift is a doable afternoon for a shop with a forklift. A bolt-on lift jack tray is easiest — position, drill or use existing bolt holes on the runway inner flanges, torque to spec. Rail retrofits are more involved: you may need to remove crossmembers or ramp brackets, line up the rail sections, and shim for level so the jack rolls smoothly its full length. Our car lift parts buyers guide covers general accessory installation practice. The rolling jack’s rating must match or exceed the lift’s rated capacity divided by two. Common ratings are 4,500, 6,000, and 7,000 lb bridge jacks for 9,000 to 14,000 lb lifts, and heavier air-hydraulic units for 18,000 lb and up. Every jack ships with stackable pads; buy extra, they wear and they walk off.
When a tray is not the answer
If most of your work needs suspension off the ground and free of the tires, a two-post lift is a better fit than a four-post with a bridge jack. Bridge jacks add flexibility to a four-post, but a two-post gives you unobstructed access to all four wheels without any accessory. Our two-post parts and options guide covers that side of the world. A hybrid setup — four-post with a proper lift jack tray for storage and long alignment plates, two-post for quick wheels-off service — is what many multi-bay shops end up with.
Ready to add a lift jack tray or a bridge jack to your four-post, or need to confirm fitment against your existing runways? Call Auto Lift Services at 800-674-9302. Give us the lift brand, model, serial number, and rated capacity and we will confirm the right tray or rolling jack, capacity-matched and rail-correct, before anything ships.
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