How BMW Built the New 3-Series for "Effortless" Speed

A new adaptive damper system and a stiffer body should help BMW get the 3-Series back to its title of "Ultimate Driving Machine."

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Máté Petrány

When we say the Genesis G70 is more of a 3-Series than the actual 3-Series, BMW has to come up with an answer. And they have: Please meet the all-new 2019 BMW 3-Series. Based on the specs, it promises to be a rather good base for an M3, that's for sure.

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But what's your take on the exterior? The new 3 is lighter, sleeker, wider, taller and longer, and you get more dramatic grille nostrils than ever. BMW's team at the Paris Motor Show was also confident enough to tell me that "what you see here is not a small 5-Series." The spectators I've talked to today seemed less enthusiastic about BMW's evolutionary design approach, but since the technology applied to the car is advertised as "all-new," I wanted to find out whether its what's under the metal that really counts. With that in mind, I've turned to two BMW employees: Peter Langen, Senior Vice President of Driving Dynamics, and Robert Rothmiller, Functional Design and Integration Driving Dynamics.

Peter Langen isn't new to this game, and says that if there's one thing that makes the 3-Series a benchmark, it's precision. And that comes from the understanding of the interaction between body and chassis components. The body structure and suspension mountings are up to 50 percent stiffer, depending on how you measure. There are new parts like the limited-slip differential, which works with the traction control and the steering. Compared to the one in the current 3-Series, the steering rack is faster, and the differences between driving modes have been dialed up as well, giving you a lot more feedback in Sport mode. Spring rates are increased by 16 percent in the lowered M Sport suspension, as well as in the optional adaptive M suspension.

BMW says the real magic is here, in this new damping system—a non-electronic setup that's different from the one used in the 8-Series. Rothmiller said this about BMW's "damper within a damper":

It's different from front to rear axle. On the front axle, we have a hydraulic rebound stopper, which is basically an additional ring on the piston rod, which dives into a slightly smaller inner cone on the top side of the damper. So for rebound, when the car is moving upwards, it prevents you from maxing out. On the rear axle—as we have a 3-Series with potentially 1100-1300 lbs. of extra load [from passengers, cargo, and potentially a trailer]—we do not need that much of a rebound. We need compression, so we have a compression stop which is basically underneath the normal valve. It’s an additional valve, which again dives into a smaller inner tube on the compression side, the lower part. If you’re driving on an undulating road, the front axle helps you throwing out, the rear axle helps you diving in, or pushing through. We call it the "skyhook." You’re hooked to the sky and never lose the horizontal position.
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The engineering team optimized front and rear axle kinematics years ago to end up with a front end that's more agile, with better mechanical feedback, and a rear end that produces less camber, hence less tendency to oversteer. This gives the car a neutral handling balance, which, coupled with the car's 50-50 weight distribution, helps build driver confidence.

One of their claims is that the 2019 3-Series isn't tuned for a single extremely fast lap (like an M3), but many effortlessly quick ones. Which should make more than 99 percent of future 3-Series buyers very happy indeed.

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