The whole theory behind the design and manufacturing of an asymmetric lift is NOT just having long arms for the rear of the vehicle and short arms for the front of the vehicle.
The term asymmetric, as it applies to above ground lifts, is used to describe the way the car is lifted. A car or truck that is lifted symmetrically will have an equal amount of the vehicle in front of the column and behind the column. Most long wheel-based vehicles need to be lifted symmetrically. A car or truck that is lifted asymmetrically will have about 30% of the vehicle forward of the column and 70% of the vehicle behind the column. The popular concept behind lifting a vehicle "asymmetrically" is linked to the notion that the asymmetric configuration allows the operator easier access through the driver's door.
No base plate lift can be a TRUE ASYMMETRIC LIFT! A base plate lift can have short front arms and long rear arms; but this does not make the base plate lift an asymmetric lift.
To properly "load" any vehicle onto an asymmetric lift; all the arms (lift pads) need to be pointing toward the rear of the vehicle. The vehicle is moved forward between the columns and the vehicle's front wheels are positioned so that they are "just past" the front side of the columns.
The two shorter front lift arms are then moved to about a 90 degree position to the column, and the lift pads are placed under the appropriate front lifting points of the vehicle. The two longer rear arms are then moved to allow the lift pads to extend to the rear of vehicle, and the lift pads are positioned under the correct rear lifting points of the vehicle.
This initial positioning of the arms (all lift pads pointing to the rear of the vehicle) CAN ONLY be accomplished on an overhead style above ground two post lift. The front arm pads could not be moved to face the rear of the vehicle if there was a raised metal plate on the floor between the two columns. The shorter front arms could only be positioned in an asymmetric lift configuration if the arm carriages were raised high enough to allow the two front arms to "clear" the base plate when moved to face the rear of the vehicle. If the arms were raised higher in the air, then the lift pads would be too high to clear the underside of many "low slung" or average height vehicles.
Atlas® base plate lifts have specially modified carriages that allow the carriage to go all the way to the floor and position the arms at the lowest possible height. The carriages on Certain Competitors base plate "asymmetric" lifts do not go all the way to the floor. The carriage is restricted (cannot go all the way to the ground) by the height of the base plate. The lifting pads on Certain Competitor's base plate lifts are then positioned too high for many of the normal and "low-slung" vehicles.
As discussed in the comparison between overhead and base plate lifts; the overhead two post lift offers more stability than the base plate two post lift because of the overhead beam between the columns. This is very important reason why OVERHEAD two post lifts should be used for HEAVY vehicles (pickup trucks with more weight in the front) in an asymmetric configuration.
The weight of a vehicle must be evenly distributed on a two post lift. The operator must remember that whether the vehicle is lifted either in a symmetric or asymmetric configuration, the weight of the vehicle must be evenly distributed on each of the four arms.
The old myth that two post lifts, with symmetric arm configurations, will "not let the operator get out the car" is unfounded. If you want to learn how to position a vehicle between the columns of a two post lift with symmetric arms and still be able to open the driver's door; then call the lift professionals at Greg Smith Equipment Sales for all the answers.