A service manager at a West Des Moines dealership called us in February because his techs were losing time on wheel bearing jobs — hub presses, brake work, anything that needs the wheels hanging free and the tech standing upright underneath. He had four bays and only one machine that could do it comfortably. That call turned into a site survey, and the survey turned into two new automotive two post lifts replacing a pair of tired drive-on units. We are based in Ames and we do this survey work across central Iowa constantly, so here is what we actually measure, why each number matters, and how wheel-off service specifically shapes the equipment decision.
Rotary and Challenger for commercial service bays, BendPak and Atlas for lighter-duty shops. Tell us your bay dimensions and slab thickness and we will tell you exactly which models fit before you spend a dollar.
Why Wheel Bearing Work Demands a Two-Post
Wheel bearing service is the job that separates a two-post from everything else in the shop. A hub assembly replacement on a modern front-drive car means the wheel comes off, the caliper and rotor come off, the axle nut breaks loose, and often a press or a slide hammer comes into play. All of that wants the suspension hanging free and the hub at a comfortable working height — roughly chest level for the tech, which puts the frame contact points somewhere between 48 and 60 inches off the floor.
A drive-on rack with a rolling jack can do the job, but the tech is reaching around the runway and the wheel well is partly boxed in. On a two-post, the entire wheel area is open air. That West Des Moines shop timed it: a front hub on a common midsize sedan ran about forty minutes on the drive-on with the rolling jack and about twenty-five on a two-post. Multiply that across a winter’s worth of Iowa road-salt bearing failures and the equipment pays for itself in labor recovery. This is why automotive two post lifts remain the default bay machine in almost every dealership service department we walk into, even shops that also run alignment racks and mobile columns.
Measuring the Bay Before Anything Else
Our site survey starts with a tape measure and a notebook, not a catalog. We record five dimensions in every bay: clear width wall to wall, clear length from overhead door to back wall, clear ceiling height at the lowest obstruction, distance from the intended column locations to the nearest control joint or slab edge, and the location of the electrical panel.
For a standard 10,000 lb two-post, the columns sit roughly 11 to 12 feet apart on centers, and we want at least 12 feet of usable bay width so a tech can walk past an open door. Fourteen feet is comfortable. Bay length should be 24 feet minimum for cars and light trucks, and we want the driver’s door of a full-size pickup to clear the column when the truck is centered. Ceiling height is the hard limit: overhead-style units generally need 12 feet of true clear height, and “true clear” means below the light fixtures, below the door track, and below any sprinkler head. In West Des Moines the dealership had 13 feet 6 inches in three bays and 11 feet 9 inches in the fourth where a mezzanine cut in. Three bays got overhead machines and the short one got a baseplate model. That is a normal outcome — most multi-bay shops end up with a mix.
Slab Thickness, PSI, and What We Do When It Falls Short
Concrete is where install prep succeeds or fails. Manufacturer minimums for most 10,000 lb two-post models are four inches of 3,000 PSI concrete, and we want six inches for 12,000 lb and above. We core-test rather than take anyone’s word for it, because we have been told “five inches” and found three and a half more times than we can count.
Anchor placement matters as much as thickness. We keep every anchor at least six to eight inches from any control joint, expansion joint, or slab edge — concrete near a joint has no lateral confinement and an anchor there can spall the edge out under load. If the survey finds a column position landing on a joint, we shift the layout a few inches or, if that compromises the drive-through, we cut and pour new footings. A typical footing pad we pour for automotive two post lifts is about five feet square and twelve inches deep with rebar tied into the surrounding slab, and it gets a full 28-day cure before anchors go in. That dealership needed one pad because a bay expansion in the nineties had left a cold joint right where a column wanted to sit. Our guide to concrete requirements for lift installation goes deeper on cure times and anchor torque values if you want the full detail.
Arm Configuration and Low-Profile Reach
Arm geometry is the spec most buyers ignore and then regret. A symmetric two-post has four arms of equal length and centers the vehicle between the columns — great for trucks and vans, and it puts the doors right at the column. An asymmetric design uses shorter front arms and rotated columns so the vehicle sits back, giving door clearance for cars. Most dealership bays we equip go asymmetric or versymmetric because the mix skews toward passenger vehicles.
For wheel bearing and brake work specifically, the pad reach and the minimum pad height matter more than capacity. Low-profile arms drop to roughly three to three and a half inches at the pad, which is what you need for a lowered car or a modern sedan with aggressive rocker cladding. Reach matters at the other end: a long-arm option that extends past 70 inches lets you get behind the front wheels of a crew-cab pickup without contorting the arm angle. We had a customer in Huntington Beach ask specifically for low-profile arms on a 10,000 lb unit for exactly this reason, and it is a request we hear weekly. When you spec automotive two post lifts, ask for the minimum pad height and the maximum arm reach in inches, not just the capacity sticker. Those two numbers determine what actually rolls into your bay.
Capacity: Do Not Buy for the Car You Have Today
The number one sizing mistake is buying capacity for the current fleet. A shop tells us their heaviest vehicle is 6,000 pounds and they want the cheapest thing that lifts it. Then a three-quarter-ton diesel shows up on a Tuesday and the tech has to turn it away.
Our default recommendation for a general service bay is 10,000 lb. That handles essentially every passenger car, crossover, half-ton pickup, and most three-quarter-tons with room to spare. Step to 12,000 or 15,000 lb when you regularly see one-ton duallies, cutaway vans, box trucks, or dually service trucks. Above that you are into 18,000 lb and up, which is a different bay conversation involving column height, arm design, and usually a taller ceiling. Capacity also interacts with slab spec — the 12,000 lb and up machines want six inches of concrete, so the decision cascades. The West Des Moines dealership went 12,000 lb on both new units because their truck department was growing and the incremental cost over 10,000 lb was modest compared to redoing the install in five years. If you are weighing capacity against budget, our breakdown of how to choose two-post lift capacity lays out the tiers plainly.
Utilities, Air, and the Order of Operations
Once dimensions and concrete are settled, we sequence the utilities. Electrical comes first: a dedicated circuit for the power unit, typically 30 amps two-pole for a 3 HP single-phase motor, with 10 AWG copper up to about 75 feet and heavier beyond. A lockable disconnect goes within sight of the machine, usually on the column or the adjacent wall around 54 inches. Air comes second — most two-post models need shop air only for the automatic lock release, and a quarter-inch line at 90 to 120 PSI is plenty.
The order matters because conduit stub-ups have to miss the anchor pattern. We have walked into more than one job where an electrician ran a floor stub exactly where a column base plate needed to sit, and the fix was breaking concrete on a Saturday. So: survey, confirm layout with chalk lines on the actual floor, mark anchor positions, then let the electrician rough in. Only after that do we set columns, plumb them, torque anchors to spec, and run the hydraulic and cable connections. On automotive two post lifts the plumb check is critical — a column out of plumb by even a small margin will bind the carriage and chew a slider block within a year. We shim to spec, verify with a level on two faces, and re-torque anchors after the first loaded cycle. Then we load-test with a real vehicle before we hand over the keys.
What a Good Install Day Looks Like
A well-prepped install of two automotive two post lifts in a working dealership is a one-day job per bay, sometimes two bays in a day if the concrete is good and the electrical is already roughed in. We arrive with the columns, arms, power units, hydraulic lines, and the correct anchors — not whatever came in the box, since we spec anchors to the actual slab we cored. Columns go up, get plumbed and anchored, carriages get cabled and equalized, the power unit gets mounted and wired, and then we bleed the system and cycle the machine empty a dozen times before a car touches it.
Then we train. Every tech who will use the equipment gets a walkthrough on lock engagement, pad placement for unibody versus frame vehicles, and what to do when a lock does not seat. That last item is where most shop injuries come from. We finish with a signed load test and a maintenance schedule — cable tension check and lock function at 90 days, fluid level and anchor torque annually. If your West Des Moines or central Iowa shop is planning a bay build, a bay conversion, or just replacing a machine that has gotten sloppy, call us at 800-674-9302 and we will come measure. The survey is the cheapest part of the whole project and it prevents nearly every expensive surprise we have ever seen.
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