What is a platform?

Retired product planner Burton Bouwkamp wrote: “We (Chrysler engineers) defined a platform by the horizontal and vertical dimensions from the centerline of the front wheels to the cowl (base of windshield) and to the H point (the hip joint). Said another way, the cowl position and driver position relative to the front wheels defined a platform. The K and E bodies were the same platform.”

Bob Sheaves wrote that this method continued until the introduction of CATIA, which was phased in around 1990, starting with the T3000/BR (1994 Dodge Ram) program; different projects continued to use the proprietary Chrysler CAD/CAM system, which used the older set of dimensions to define a platform, while new projects started with a definition of the platform as the suspension, driveline, and (the single most expensive component) the pan stamping, which was the floorpan and firewall. The transition period was presumably awkward, as different departments moved to CATIA at different times, or could use CAD/CAM and its platform definitions for some vehicles and CATIA with its platform definitions for others.

At the same time, the platform’s starting point was moved to one meter forward of the front wheel, avoiding the use of negative numbers on one side of the vehicle when the right/left dimensions were measured from the center.

After noting that a platform was defined in this manner, Bob Shaves wrote, “By the logic some people express, such as the Prowler using the LH platform, one could also say the Viper was built from the Dakota platform, or the minivan shares the Neon platform. [This is obviously not true.] Some people toss around specific engineering terms with no knowledge of the true meaning, and others pick up the use and think that it's the correct usage of the term.” But, Bob continued, a platform is defined by a set of dimensions, not the powertrain, architecture, or appearance. Thus, the Plymouth Reliant was not on the same platform as the Plymouth Acclaim, though they have numerous similarities in other ways, and the Acclaim is based on the Reliant.

The importance of this distinction is that platform sharing is not necessarily a bad thing. A Dodge Avenger, Fiat, and Jeep Liberty can be brothers under the skin, and yet have two entirely different personalities. Parts sharing does not mean platform sharing, and platform sharing does not mean parts sharing. The Reliant, 600ES, Limousine, and Caravan, despite having major differences in appearance, handling, length, height, etc., were on the same platform (as defined at the time), and would be even if they did not also have very similar suspensions and engines. Very different vehicles can be on the same platform and very similar ones can be on different platforms — the first generation Neon and Stratus being an example of the latter.

As time went on and technology changed, new definitions were adopted. A platform is now defined as a collection of fixed hard points, so that different vehicles with the same points can be built on a single assembly line, with similar crash characteristics. This greatly cuts development costs and increases factory flexibility, so that the product mix can be altered very rapidly without additional cost as customer tastes change.