The Germans completely dominate the compact luxury coupe market, and now there’s a new big-grilled choice on the market: the 2021 BMW 4 Series. BMW has chosen to reveal the car in base 430i form and hotter M440i xDrive trim. Because no stone is ever left unturned by the German competition, this car already has competitors that are creepily similar to it from nearly every aspect.
Homogeneous is the best way to describe the three cars we’re pitting against each other. Some things are noticeably different, like the design, but finding a clear winner from the numbers is no easy task. Even as the 2021 BMW 4 Series is totally new, both the Mercedes-Benz C-Class Coupe and Audi A5 Coupe are recent designs. That means everybody is on a relatively even footing going into this.
And just to be clear, we’ve kept this comparison to the standard versions of the 4 Series and its competition, because the M4 hasn’t been revealed yet. When it does, we’ll have plenty to talk about between the Mercedes-AMG C 63 Coupe and the Audi RS 5 Coupe. Without further ado, here’s the comparison chart. Some figures are highlighted so as to point out a win for that model over the others.
Every single car in its base form uses a 2.0-liter turbocharged four-cylinder engine. BMW ties with Mercedes in horsepower at 255 horses, but Bavaria takes a convincing lead with its stout 294 pound-feet of torque. The 21 pound-foot advantage over both the C 300 Coupe and A5 Coupe is likely enough to be noticeable in acceleration, and the 0-60 mph times show exactly that.
BMW is faster than everybody to 60 mph, according to the manufacturer estimates, coming in at 5.5 seconds with rear-wheel drive or 5.3 seconds with all-wheel drive. The advantage over Mercedes is rather large, but the Audi is right behind BMW. They use different transmissions to get there. BMW uses one of our favorites, the ZF 8-speed automatic; Mercedes uses its own nine-speed automatic transmission, and Audi uses a dual-clutch seven-speed transmission, which is also an inside job. All of them behave a bit differently in practice, but the BMW and Mercedes should be inherently smoother than Audi's sportier dual-clutch transmission.
We don’t yet have fuel economy for either BMW engine, but Audi is firmly ahead of Mercedes in this category. We’ve been impressed with the real-world fuel economy out of the 3 Series so far, and we imagine the 4 Series will offer similarly impressive results.
BMW manages to differentiate itself with its M440i xDrive. While the Mercedes and Audi competitors use V6 engines, BMW has put its excellent 3.0-liter turbocharged inline-six under the hood. We’ve driven multiple cars with this engine (including the 2021 Supra), and it’s splendid in sound, power delivery and sheer thrust. The 48-volt mild-hybrid electrical system is a neat bonus, too.
Despite all of that, the Mercedes-AMG C 43 still wins from a numbers perspective, as the twin-turbo V6 produces a hair more horsepower and 20 pound-feet more torque. It also has Mercedes’ multi-clutch automatic transmission, whereas the other two make do with traditional eight-speed automatics. That doesn’t seem to help in the 0-60 mph department, though, as BMW still estimates its M440i is quicker than both the Mercedes and Audi S5. As these cars are only a tenth or two different from each other, though, the difference is negligible.
All three of these cars are mighty similar, but if we’re going to assign a performance winner on paper, it’s going to be the BMW. Both versions of the 4 Series are quicker to 60 mph than the others, and the sweet inline-six engine is enough to have us leaning its way. The gap is close, though, and driving all of them back-to-back could easily sway us in a different direction.
BMW: top; Audi: bottom left; Mercedes-Benz: bottom right
Here’s where BMW has thrown a curveball in this small coupe battle. The 4 Series is about three inches larger than both the C-Class Coupe and A5 Coupe. It’s also wider than the others, and falls in the middle when it comes to overall height.
That extra length leaves the 4 Series as the clear winner in the all-important rear seat legroom category. It’s a full 2.5 inches larger than the Mercedes and 1.8 inches larger than the Audi. It’s still relatively small at 34.5 inches, but backseat passengers will definitely be more comfortable in the BMW than the others. Unless they’re especially tall, because BMW comes in last place for rear headroom. Audi leads the way here with 36.1 inches. Coupes are inherently limiting in head space for rear seat passengers, so it’s no surprise to see a bunch of low numbers in this category.
When it comes to trunk space, the numbers say BMW has a clear advantage. However, as we found in our BMW 3 Series luggage test, the numbers aren’t telling the whole story. BMW’s way of measuring the space appears to be different in some way compared to others. Until we can physically start shoving luggage into this coupe, we’re going to refrain from declaring it the ultimate utility coupe.
BMW has priced both the 430i and M440i to almost perfectly line up to Mercedes. At $46,595, the 430i is just $350 cheaper than the C 300. The A5 Coupe is the cheapest of the bunch at $43,895.
The S5 is also the cheapest performance variant, coming in about $6,500 cheaper than the M440i and C 43.
For the budget-conscious, the S5 Coupe is a great way to get into a hot German car for less. However, maybe you’re a fan of the grille. If so, the new M440i could be your kind of vehicle. It certainly stands out more than the others and makes a grander (for better or for worse) entrance than any of its peers. We'll also note the existence of the Lexus RC and Infiniti Q60 alternatives, both of which offer solid performance variants but don't completely matchup to the Germans. If there were a Japanese wildcard in this fight, it's the RC F and its impressive 5.0-liter naturally aspirated V8 engine.
Now, check them all out in photos.
2021 BMW 4 Series Coupe
Mercedes-Benz C-Class Coupe
Audi A5 Coupe