Mercedes-Benz currently sells 16 different model lines in the US, not counting body styles like coupes and convertibles, hot AMG offerings, or high-end Maybachs. What we're saying is: Mercedes has a lot of cars and it's easy to get them all confused, especially when some of these vehicles are practically in the same segment.
That's especially true of the GLA and GLB, two pint-sized crossovers that use the same platform, powertrains, share interior bits, and have similar dimensions. Their distinctive styling sets them apart, at least, but outside of looks, what is it exactly that makes these two vehicles differ from one another?
We lined up the Mercedes-AMG GLA 35 and GLB 35 side-by-side to pour over each and every detail in an effort to find out what makes these two very crossovers different (and what makes them the same). Not only that, but we also wanted to definitively come to a conclusion as to which of these two crossovers is our favorite, even though you really can't go wrong with either.
The most notable difference, as mentioned, is the way these two crossovers look. The GLB adopts a boxy profile that we haven't seen on a true crossover since the GLK – remember that? The headlights are “squircular,” the windshield is raked upright, and the roofline is tapered high and tight like a good haircut. The GLB is very interesting to look at, and in the AMG 35 trim tested here, it wears the Panamericana grille and other sporty exterior bits. Our car also gets AMG-specific 21-inch matte black wheels, which are a $2,050 option but only available with the Night Package, itself another $750 option.
The GLA is a much sleeker-looking vehicle. It wears new sheet metal for the 2021 model year, slimmer headlights, and unlike the GLB, has a svelte coupe-like profile with a dramatically sloping roofline. Even though this GLA is also an AMG 35 model, it wears the shiny, no-cost 19-inch wheels rather than the flashy 21 inchers on the GLB.
Looking at the two cars together it's obvious the GLB is the larger of the two; it has a 111.4-inch wheelbase and stretches out to 183.1 inches total. The GLA is slightly smaller with a 107.4-inch wheelbase and a total length of 174.6 inches. The GLB is also noticeably taller, standing at 65.4 inches tall versus the GLA's 62.5 inches. Here's how the two cars compare in every dimension:
|Wheelbase||Length||Height||Width||Ground Clearance||Curb Weight|
|Mercedes-AMG GLA 35||107.4 inches||174.6 inches||62.5 inches||79.5 inches||4.6 inches||3,704 Pounds|
|Mercedes-AMG GLB 35||111.4 inches||183.1 inches||65.4 inches||79.7 inches||4.8 inches||3,871 Pounds|
What's interesting, though, is that while the GLB is longer and taller than the GLA by a good bit, the interior dimensions are similar. The front headroom in the GLB is 40.7 inches compared to the GLA's 39.0, and there are 0.4-inches more legroom in the front compartment of the GLB. The GLB's seconds row offers 39.3 inches of headroom to the GLA's 38.0 inches of headspace, and the GLB has 38.1 inches of legroom to the GLA's 38.0. But the one thing that the GLB has the smaller GLA doesn't is an optional third row of seats – even though the 29.1 inches of legroom makes it essentially unusable for normal-sized humans.
As far as cargo goes – obviously the GLB has a bit more room. There are 27.0 cubic feet behind the second-row and 62.0 cubic feet with those seats folded flat. The GLA, meanwhile, has just 15.4 cubic feet behind the second row and 50.5 cubic feet what that row folded flat. Put cargo space in the win column for the GLB.
|Headroom||Shoulder Room||Legroom||EPA Passenger Volume||Cargo Volume|
|Mercedes-AMG GLA 35||39.0 / 38.0 inches||56.0 / 55.0 inches||41.0 / 38.0 inches||99.0 cubic feet||15.4 / 50.5 cubic feet|
|Mercedes-AMG GLB 35||40.7 / 38.7 / 34.8 inches||55.9 / 55.0 / 43.8 inches||41.4 / 36.9 / 29.1 inches||125.0 cubic feet||5.1 / 24.0 / 56.7 cubic feet|
And then there’s the price. These two vehicles aren’t that far apart before options, the GLA 35 starts at $47,550 and the GLB 35 costs $49,500 out of the box. If you want the base models, though, the standard GLA starts at a more reasonable $36,230, and the base GLB is just $38,050.
The most obvious similarity between these two cars is the interior. Both the GLA and the GLB have the same 10.3-inch central touchscreen and corresponding 10.3-inch digital instrument cluster, both running the MBUX infotainment system. Even the basic layout of the dash is the same, with three centralized air vents just below that massive screen and identical shift knobs and steering wheels.
These two cars share the same platform as well as the same turbocharged 2.0-liter four-cylinder. That engine is good for 302 horsepower and 295 pound-feet in both applications, allowing the GLA to hit 60 in 5.0 seconds and the slightly heavier GLB to get there in 5.1 seconds. The GLA 35 tips the scales at 3,704 pounds while the GLB 35 weighs 3,871 pounds (or 3,993 pounds in the seven-seat configuration).
Trying to pick between these two compact crossovers is like trying to decide between apples and oranges. Both of these vehicles are great and loaded with impressive tech, punchy engines, and their own distinctive style. But if we had to choose one, the GLB is more fun to look at and slightly more spacious, even if it is the pricier option of the two.
The unique styling of the GLB – especially this 35 model with all the performance-oriented bits – gives it more panache than the svelte but otherwise underwhelming to look at GLA 35. The performance of these two vehicles is nearly identical, as is the interior – which makes the GLA still worth considering. But if you want a crossover that stands out, the GLB might be the one for you… unless you want to go all out on the extra-hot GLA 45.
|2021 Mercedes-AMG GLA 35||2021 Mercedes-AMG GLB 35|
|Turbocharged 2.0-liter I4||Turbocharged 2.0-liter I4|
|302 Horsepower / 295 Pound-Feet||302 Horsepower / 295 Pound-Feet|
|Transmission:||Eight-Speed Dual-Clutch||Eight-Speed Dual-Clutch|
|Drive Type:||All-Wheel Drive||All-Wheel Drive|
|0-60 MPH:||5.0 Seconds||5.1 Seconds|
|Top Speed:||155 MPH (electronically limited)||155 MPH (electronically limited)|
|Efficiency:||23 City / 29 Highway / 25 Combined||21 City / 26 Highway / 23 Combined|
|Weight:||3,704 Pounds||3,871 Pounds|
|Cargo Volume:||15.4 / 50.5 Cubic Feet||5.1 / 24.0 / 56.7 Cubic Feet|