BMW likes to boast that it builds "the ultimate driving machine," and if any individual model has deserved that reputation, it's the 3 Series sedan.
While BMW produces a broad range of vehicles — traditional sedans, sports cars, wagons and a growing list of sport utility vehicles — no vehicle is more closely identified with the carmaker than its 3 Series.
The Bavarian automaker has sold about 4.5 million of the sedans since the 3 Series' introduction in 1975, making it the best-selling luxury nameplate in automotive history. But it has lost momentum in recent years, something BMW hopes to remedy with the launch next year of its next generation 3 Series — its seventh iteration.
The outgoing model, introduced in 2011, took a number of hits for losing its traditionally unique mix of performance, handling and luxury.
Initial reviews of the 2019 model have been overwhelmingly positive, with a headline in the influential Automobile magazine declaring the 2019 sedan "a Proper 3 Series Again."
Perhaps, but the seventh-generation sedan faces a level of uncertainty not seen since the original model, internally code-named the E21, debuted in 1975. That includes not only a wave of new competitors, but other offerings found right within the BMW showroom that reflect the dramatic market shift from sedans to sport utility vehicles.
"The 3 Series is truly the heart and soul of BMW," said Thomas Baumer, project head for the 2019 3 Series, adding that "it is truly critical" that the new 2019 model regain momentum lost by the sixth-generation sedan.
As recently as 2013, BMW set a U.S. sales record. American buyers drove off in 93,544 3 Series models. But volumes have steadily declined, dipping to just 53,470 in 2017. And the downward trend has continued this year — 3 Series sales for the first 11 months of 2018 were off by 23 percent.
There are a number of reasons why BMW may have lost momentum. The Automobile review noted that the traditionally crisp characteristics of the 3 Series became "muddled" with the outgoing model, adding, "More than a few pundits and purists have found the traditional joys of the 3 Series less present in recent years."
If that alone was the problem, the new model might be able to stage a rapid recovery. CNBC was also able to test the new 3 Series during a media drive in Portugal's Algarve region this month and found its handling precise, steering crisp and, with as much as 62 more horsepower, depending upon the model, capable of giving a motorist neck-snappingly quick acceleration.
But that's by no means the only challenge for the gen-7 sedan.
"The BMW 3 Series has been the icon in its class, and when you're the icon, everyone is gunning for you," said John McElroy, a veteran automotive analyst and host of the industry broadcast AutoLine.tv.
In years past, most competitors aimed to carve out their own niche. With its own compact sedan, the Audi A4 was focused on design, Mercedes-Benz aiming for Teutonic plushness with the C-Class. But the lines have been blurring, and those German rivals have sharply upped their own performance game, reviewers are quick to point out. So have Japanese rivals like Nissan's Infiniti and Toyota's high-line Lexus, the Japanese giant's CEO Akio Toyoda declaring the need to put more "passion" into its products.
An equally serious challenge is being posed by new entrants, such as Genesis, the luxury brand recently spun off by Korea's Hyundai. Its first entry into the compact sports sedan segment has generated intense buzz, the G70 winning the coveted Motor Trend magazine Car of the Year award.
By hiring away former BMW executives including Albert Biermann, now its R&D chief, as well as executives from Bentley, Bugatti, Mercedes and Lamborghini, Hyundai's luxury brand has been able to "build a legitimate 3 Series competitor," Motor Trend declared in awarding the G70 its trophy.
The reality is that Genesis G70 sales have been marginal so far, but there's an even bigger threat coming from California now that Tesla appears to have finally resolved the "production hell" problems at its battery and assembly plants. The all-electric Model 3 has also taken aim at BMW's "heart and soul" and is rapidly leaving the 3 Series in the dust, at least from a sales perspective. It delivered around 18,000 of the compact sport sedans last month, according to industry estimates, compared with 3,218 3 Series.
The BMW numbers may be a bit misleading, as demand typically dips ahead of the launch of a new model. Sales for the 3 Series fell 47.9 percent year over year in November. But even using year-earlier figures, the Model 3 would have outsold the 3 Series by nearly 3 to 1.
There's an even bigger challenge, said analyst McElroy. "People are drifting away from sedans to SUVs and CUVs, so the biggest competitor may be the product on the other side of the BMW showroom."
Indeed, in sharp contrast to the declining demand for the 3 Series, BMW's compact crossover utility vehicle, the X3, posted a 77 percent year-over-year sales jump last month, while year-to-date demand is up 45.1 percent.
And it's not just the 3 Series that has seen sales upended. BMW passenger car sales, on the hole, were down 2.5 percent in the U.S. through the end of November. The brand's crossover lineup — or sport activity vehicles, as it prefers to call them — rose 10.8 percent year over year.
BMW officials contend that their goal isn't to make the 3 Series the best-selling compact sport sedan in the industry, just the one that sets the benchmark for performance and handling. It may not be number one, but it's the model that continues to define the brand, whatever model you're talking about, sedan, coupe, wagon, sports car or sport utility vehicle.
And from the standpoint of the initial reviews, that's where the new 2019 BMW 3-Series is truly delivering.
Disclosure: Paul Eisenstein is a freelancer for CNBC. His travel and accommodations for this article were paid by an automaker.
