Performance & drive
What it’s like to drive, and how quiet it is
Engine, 0-60mph and gearbox
From a range of four engine options, two are diesels and two are petrol. The entry level one is a 1.3-litre petrol, badged 200 and making a healthy 161bhp, but quite high in the rev range. That’s not a problem if you pootle around town by yourself, but add passengers and/or tall hills to the equation and you need to push the engine quite hard to get decent performance out of it. The other petrol engine is a 302bhp 2.0-litre petrol that’s fettled by AMG; cars with this engine are badged GLB 35 and will be available to order at a later date. With this engine, though, there isn’t another seven-seater SUV of this size that’s so eager to accelerate, thanks in part to its standard-fit launch control system.
Putting the AMG 35 aside and concentrating on sensible all-rounders, the two diesel engines have more low-down urgency than the 200 petrol and feel faster in most situations. You can choose between two versions, badged 200d (148bhp) and 220d (187bhp). The less powerful version doesn’t really feel ideally suited to handling a big seven seater SUV, but the more muscular 220d is an ideal match for the GLB’s character. It pulls hard from about 1,500rpm onwards and will be strong enough for towing, but it doesn’t have the enthusiasm for revs that the BMW X3 20d exhibits.
The seven-speed automatic gearbox that comes with the petrol 200 engine is not the best in this class; it has a tendency to hesitate when setting off. Happily, the eight-speed automatic fitted to the rest of the range is much better in that regard. Once you get going, though, both gearboxes shuffle gears seamlessly and are eager to kickdown.
Suspension and ride comfort
So far we’ve only driven GLBs fitted with adaptive suspension. This system allows you to stiffen or soften the ride depending on the driving mode selected. Things are at their stiffest in Sport mode; this controls body movements neatly over bumpy roads, making the GLB more stable than a Discovery Sport.
In softer Comfort mode, it feels pleasingly wafty and can stomp over sleeping policemen with minimal fuss, but sometimes become too bouncy – the Audi Q5 remains rather more controlled. Don’t forget that less expensive alternatives such as the Peugeot 5008 have a supple ride, too. We’ll update our review as soon as we’ve driven a GLB on standard, non-adaptive suspension.
If you’re searching for outright fun behind the wheel, you’ll be better served by the BMW X3. Even the lowered and stiffened AMG 35 can’t disguise its relatively high centre of gravity; it leans in corners and doesn’t feel as tied down as the best handling cars in this class. The steering of non-AMG versions of the GLB, meanwhile, is so light that it causes you to feel quite detached from the process of driving.
It does have plenty of positive qualities in this category, though; grip is strong and the car generally feels eager to change direction. The stability control system, however, as is the case with other Mercedes models, is a bit too keen to reign in on the fun, should you drive the GLB a bit more forcefully.
Noise and vibration
The 200 petrol engine is impressively hushed on the motorway, but work it too hard and it makes its presence known. It’s pretty free from vibrations to the controls, though, making it a peaceful cruising companion. The AMG 35 has a noticeably louder engine, but it’s not particularly entertaining to listen to, in part because what you hear from the inside is augmented via the speakers.
The diesels are impressively hushed at a steady speed, but vibrations through the steering wheel intensifies the harder you push them, as does the grumbling from under the bonnet. The Audi Q5’s diesels are just that bit smoother and quieter.
The boxy shape of the GLB whips up more wind noise at speed than most rivals, and, if you go for the large wheels, road noise on coarse surfaces is pronounced. It’s a close match to the Land Rover Discovery Sport in this regard.