A45s roll down the same line and at the same time as ordinary As, although they get wider wings and tracks and some body stiffening brackets – two welded near the front wheel arch, the others bolted around mostly under the body.
But AMG, Mercedes’ alternative to BMW’s M Division, is, above all else, an engine builder. Its un-woke ‘one man, one engine’ build principle sees that each 1991cc four-cylinder fitted to 45s is hand-assembled by one technician at AMG’s Affalterbach base before being crated to the A-Class production line.
It’s a complex unit in itself, and things get fairly complicated behind it too. The engine drives through an eight-speed dual-clutch automatic gearbox to all four wheels, with the rears via a propshaft which is always turning at the geared speed. Two clutches either side of the rear differential, recent Ford Focus RS-style, distribute power left or right as they see fit – which means under acceleration and cornering, really. In constant-speed cruising they’re pretty idle.
They can distribute as much torque as the rear axle receives to whichever side they choose – up to 100% of it per side. The system can’t deliberately push more than half of the engine torque to the rear wheels, but in theory the back wheels could be receiving more than 50% of available torque if, say, the body was heavily loaded on the way out of a slippery corner and the fronts were scrabbling. It rarely works like that, though, and, if it does, for no more than a moment.
How does the AMG A45 let the driver access its power?
As you might expect, Mercedes has opted for a lot of drive modes to accommodate all of this. Probably too many, within a cabin that already has rather a lot going on. It’s designed pleasingly, though, with lovely turbine-style air vents that I’m very fond of and a high-resolution instrument pack and central screen.
But oh my, there’s some tech overload. On the instrument binnacle, pick one of the several options for showing a speedometer on the left, and you’ve still got seven other choices for how the rev counter looks to the right of it. There’s another display in the middle of those two, too. The steering wheel has 17 buttons or levers attached to it, and two of those are multi-function track pads. And yet turning off the lane keep assist is buried in the main centre screen menu.
I’ll go on. There are five drive modes, or six counting the customisable ‘Individual’ one, which encompasses four ‘AMG dynamic’ modes (how the stability, transmission and four-wheel-drive systems operate), three damper settings, two exhaust modes (although these also vary by drive mode) and two steering weights which you can’t select yourself – some settings are barely heavier than the others. ESC can be on, in Sport, or all off. And there’s a ‘drift mode’ (it doesn’t disconnect the front wheels but puts even more emphasis on an outer rear wheel) and launch control.
Apparently some markets really like all this. I just wanted to trust what the engineers thought was best and have the relative simplicity of a Alpine A110 or a BMW M2. But no question, it’s effective. The A45 is a bit brittle at low speeds but settles as you get faster, combining good straight-line stability with terrific mid-corner agility and response given that, at 1625kg, it’s relatively heavy for a 4.4m car. The electronics can tweak an inside rear brake on the way into a corner to help turn-in, and as soon as you get on the power it pushes power to the outside rear for a really positive rotation – no need for anything like active rear steer here or, as might be needed in some cars, to give it a bung and lift off. It feels very positive but quite natural.