2021 Mercedes-Benz GLB

From far away it looks big. Bucking the 2020s trend of hatchback-like small SUVs with sloping roofs, the Mercedes-Benz GLB is tall and square. But while the proportions are roughly the same as the automaker’s full-size GLS-Class SUV, the GLB is a small machine. At 182.4 inches long, it’s smaller than the Acura RDX, Audi Q5 or Mercedes-Benz’s own GLC-Class. Open the doors, however, and the design intent becomes clear. That boxy look creates a huge interior.

Inside, the GLB boasts more overall cargo volume and rear-seat legroom than all three of those competitors and most of its class. The GLB even offers an optional third row, one of only two compact premium crossovers to do so.

This space comes from the company’s clever re-engineering and stretching of the smaller GLA-Class. Introduced for 2020, the GLB rides the same platform as the GLA and uses most of the same mechanical pieces. The extra weight of the larger GLB means more sedate performance, but as a hauler, it excels where the tight quarters of the GLA can mean leaving things at home. 

Now in its sophomore year, the 2021 Mercedes-Benz GLB gets only minor changes, but a sportier version, the Mercedes-AMG GLB 35 joins the lineup. That brings the total number of versions to three. The front-wheel drive, base-model GLB 250 starts at $39,100 and adding 4Matic all-wheel drive (AWD) adds $2,000. The new AMG GLB 35 starts at $50,550. All prices include a $1,050 destination fee.

Like the GLA, the GLB 250 models are powered by a turbocharged 2.0-liter four-cylinder engine making 221 horsepower and 258 pound-feet of torque. Both front- and all-wheel drive models use an eight-speed dual-clutch automatic transmission, and there are driving modes that alter the behavior of both the transmission and the optional four-wheel drive system.

There’s more than enough power for most drivers, but there’s noticeable turbo lag and the engine gets loud when pushed for power and winded on long, steep grades. There’s lots of wind and road noise on the highway, too, distinctly unlike the serene quiet of the larger GLC. 

Though there’s plenty of noise, the GLB is light on gas, with both 250 models returning 26 mpg combined, which is better than most competitors save for the Lexus NX hybrid. Our tester returned closer to 25 mpg, but nailed its city mpg target at 23 mpg.

The GLB handles well for a big and tall SUV, thanks to its car-like underpinnings (which are also shared with the A-Class and CLA sedans). It’s not an athlete like the BMW X3, but it’s predictable and neutral. The 4Matic AWD system is highly capable on snow, ice or gravel trails, and features different drive modes. It puts power to the wheels where it will be used best with a minimum of wheelspin or fuss, but the GLB isn’t really meant for serious off-roading. 

The AMG GLB 35 uses a more powerful version of the same 2.0-liter engine but returns 302 horsepower and 295 pound-feet of torque, but uses the same eight-speed gearbox. An inch lower and wearing aggressive styling with low-down spoilers, skirts and wheels from 19 to 21-inches, the GLB 35 brings lively but strictly on-road performance.

The most important option for most GLB shoppers will be the $850 optional third-row. Only one other premium compact crossover offers a similar option, the Land Rover Discovery Sport, and the third rows of both vehicles are tiny.

Mercedes-Benz actually puts a warning label on the door jamb indicating that the third row is strictly for persons under 66.5 inches tall, and even little kids will find it hard to access. Even with munchkins back there the second row has to move forward, so it’s a real compromise in comfort. 

Without the third row, however, the interior feels vast. There’s plenty of room for front passengers and the seats are comfy and supportive. There’s more rear-seat head and legroom than most rivals, though Lincoln’s Corsair bests the GLB in a couple of dimensions, and a six-foot-five adult can sit comfortably in back on a long trip. It’s also a kid-friendly space, easily configurable with huge side doors and lots of room for baggage if you don’t opt for the third row.

Sans third row, the GLB offers 27 cubic-feet of cargo space behind the rear seat, a 40/20/40 sliding unit, and 62 cubic-feet with it folded. That’s far above average and falls just shy of the larger BMW X3 (62.7) and Volvo XC60 (63.6). The third row eats up 3 to 4 cubic-feet of space, and with it in place, there’s just 5.1 cubic-feet of cargo room behind it.

While spacious, the GLB doesn’t feel quite as rich as the GLC or some other luxury rivals. The cabin materials are nice, but the standard equipment list is stingy. Every GLB comes with power front seats, a power tilt/telescope steering wheel, a 115-volt household outlet, blind spot assist and forward automatic emergency braking, but beyond that many items cost extra.

The base models make do with a 7-inch infotainment screen and driver’s display, though they’re hidden under the same broad expanse of glass as the optional 10.25-inch units, part of the $1,750 premium package. The GLB uses Mercedes-Benz’s newest MBUX infotainment system with Apple CarPlay and Android Auto standard. It’s easy to use and very visual, but it looks best on those optional displays.

Heated seats or, separately, heated and ventilated seats are optional, as are wireless charging, navigation, and most of the GLB’s active safety features. 

In this department, the GLB offers lots of goodies like adaptive cruise control, active lane keeping assist, evasive steering, cross-traffic alerts and braking, active lane change assist and a bevy of other features, but they’re part of a $1,700 driver assistance package. That isn’t too high a price to pay, but some competitors offer these features standard. In terms of crash tests, the GLB hasn’t been evaluated by the IIHS yet, but NHTSA gave it a four-star overall rating.