ROCKENHAUSEN, Germany – With an eye on the bottom line, the auto industry is eager to commonize as many vehicle parts as possible – across platforms, brands and even from auto maker to auto maker.

But some components, including the seemingly basic, do not lend themselves to standardization.

Consider the seat recliner. Every new car in the world has one, and a growing number are powered. A simple metal stamping acts as a geared hinge, allowing the seat back to pivot forward for easier access to back seats.

Surely, one design should fit all, but that is not the case.

Keiper GmbH & Co. KG produces at its plant here one of the most popular seat recliners in the world, the Taumel 2000, at a rate of 215,000 units a day on five assembly lines. Production began in 1996, and within four years total output reached 100 million units.

The plant produces 350 different versions of seat recliners for 60 customers.

Standardization is difficult because every seat has unique dimensions, says Juergen Swarofsky, manager of international coordination for Keiper’s corporate sibling, Recaro GmbH & Co. KG, maker of racing and high-performance automotive seats.

“Every recliner must have a different shape and different attachment points,” Swarofsky says, adding that engineering one recliner to fit all seats likely would cost too much. Modifying the Taumel 2000 recliner for a new seat program, on the other hand, requires minimal engineering.

“Once you are over 200,000 units in production, there would be no difference in the price,” Swarofsky says.

When the Taumel 2000 was launched in 1996, Keiper expected the Rockenhausen plant to handle all output with five assembly lines, at a rate of 60,000 recliners a day.

“But it (Taumel 2000) was so successful, we needed eight more assembly lines and more room,” says Wolfgang Folz, manager-single part production here.

The eight additional lines were installed about an hour away at another plant in Kaiserslautern, where Keiper also operates a technical center. Some company insiders suggest the Taumel 2000 saved Keiper during difficult times in the 1990s.

The Taumel 2000 may not reflect it, but Keiper is attempting to meet the industry’s demand for commonized parts whenever practical.

The supplier has a contract to produce 2 million seat structures annually for DaimlerChrysler AG. The massive volume is met with three common structures that are used in up to 200 different seats for vehicles such as the Dodge Durango and Magnum, Mercedes E-Class and Chrysler 300.

Keiper ships the structures from its plants in Germany and in London, Ont., Canada. Production for the seat structures began in 2004.

Here at the Rockenhausen plant, 64% of the output is seat structures, compared with 19% for recliners. The top customer, DaimlerChrysler, receives 37% of production, followed by General Motors Corp., with 26%. Overall sales from the plant in 2005 were €302 million ($385 million).

The structures consist of a series of metal stampings welded together to form the seat and backrest. Some 400 employees on seven assembly lines produce 22,000 structures per day, Folz says. Another 355 workers assemble Taumel 2000 recliners.

And even though Keiper is attempting to commonize seat components as much as possible, the Rockenhausen plant still produces 240 different versions of seat structures for 39 customers.

Keiper and Recaro merged in 1983 and together attempted to enter the European market for complete seats in the 1990s. Keiper Car Seating GmbH and Co. had two plants in Europe, one producing seats for Porsche AG, the other for BMW AG. Each delivered seats “just-in-time” to the vehicle assembly plants.

The strategy failed, however, as Keiper struggled to sell its seat structures to other auto makers and ultimately because low-volume Recaro was not a good fit with high-volume Keiper.

In 1997, the companies were restructured as separate divisions under the Keiper Recaro Group. That same year, Lear Corp. purchased the two JIT seat plants in Europe for $235 million.

The Rockenhausen plant is a significant employer in this small town 100 miles (160 km) northwest of Stuttgart.

Yet the facility – with a relatively low-tech product portfolio of stamped components – must compete with the growing capabilities of lower-wage regions, particularly Eastern Europe.

Folz says the plant produces about 40% of the components used in seat structures and recliners and purchases the remaining 60% from outside sources, some of them in Eastern Europe.

“We produce only the gears or the added-value parts here,” Folz says.

The plant’s 900 workers belong to the IG Metall trade union. Starting pay is €14 ($18) per hour, or €21 ($27) per hour with benefits, Folz says.

For five years, the plant has operated three shifts six days a week. As of September, the plant added three shifts on Sundays, as well, to meet demand for the Taumel 2000.