Jeremiah 29:11

Platform sharing: Your cars' tangled family tree
When someone says one car is 'based' on another, that could mean a lot or almost nothing.

By Peter Valdes-Dapena, CNNMoney.com staff writer

NEW YORK (CNNMoney.com) -- You will often hear people, especially car writers, say that one car is "based on" another or that two vehicles "share a platform." For example, they might say that the Ford Fusion is based on the Mazda6 or that the Toyota Highlander is based on the Toyota Camry.

What isn't clear is just what that statement means. By itself, it tells you a little, but very little, about what a car is probably like.

Most people assume that one car is simply a "badge engineered" version of the other. That means that the differences between the two vehicles are almost entirely cosmetic.

In some cases, that's absolutely correct.

For example, the Mercury Milan is a "badge engineered" version of the Ford Fusion. Park the two cars side by side and you'll see right away that they are, for all practical purposes, the same car with different paint jobs, grilles and lights. The Milan is a Fusion dressed in slick European-looking duds and with a few added features.

But the Ford Fusion, itself, is based on the "platform" of another vehicle, the Mazda6 sedan. (Ford owns a controlling interest in Mazda.) If you park a Fusion and a Mazda6 next to each other, though, there would be nothing to indicate that these cars are related. They aren't even the same size. The Ford is slightly larger than the Mazda.

If you were to drive the two, they don't seem terribly similar, either. The Ford has a smoother ride and feels nice, but it's a little less responsive than the quick-feeling Mazda6.

So you might wonder how these two vehicles are related. What they share is all stuff you can't see. Some of it's important - like a V-6 engine - but most of the shared parts you probably couldn't care less about. (Even though some of it - like electronics and wiring - is actually very important.)

The core
Because vehicles are spoken of as being built "on" a certain platform, there's a tendency to think of the platform as, literally, the vehicle's floorpan, the bottom of its body structure.

But, really, that's getting things a bit turned around. There are other things that must be decided first. The rest of the vehicle is engineered around those basic decisions.

When product planners and engineers talk about a "platform" or "architecture," they're generally talking about a basic type of vehicle that can be made from a few combinations of suspension, engine and transmission choices.

For starters a company might have an "architecture" for small front-wheel drive cars, another for larger front-wheel-drive cars, another for rear-wheel-drive cars and another for trucks and truck-based SUVs.

While all this might all sound terribly confining, limiting the number of basic "platforms" and sharing parts, combined with more versatile modern factories, actually allows auto manufacturers to offer more different models today than ever.

In years past, a car model was considered successful only if it sold in the hundreds of thousands. Today, cars can be profitable when fewer than a hundred thousand are sold.

That's because modern car factories are flexible enough to make several different models at the same time, assuming there are enough similarities in their basic construction. They don't have to be identical.

"The consumer is getting a little more discerning and wants a more customized solution," said Michael Robinet, vice president for global vehicle forecasting at CSM Automotive.

The key is creating platforms with enough "bandwidth," said Jon Lauckner, General Motors' vice president for global program management. Each fundamental platform has to be engineered, from the very beginning, to be flexible enough to build different, distinct veh