Mercedes-Benz SLR McLaren: identity crisis

By Greg MacLeman

| 25 Aug 2022

Classic & Sports Car - Mercedes-Benz SLR McLaren: identity crisis

What do Fernando Alonso, Kanye West and Paris Hilton have in common, aside from being filthy rich?

Not very much, with the probable exception that all three, at some point, counted a Mercedes-Benz SLR McLaren as their everyday driver; a car with the power to captivate Formula One champions, rap stars and reality television socialites, but one that over the years accumulated – at best – mixed reviews.

Not least from its designer, whose sense of pride in the project stemmed mostly from the car’s safety credentials.

Hardly a ringing endorsement for one of the most technically sophisticated supercars of the period.

The big Mercedes corners remarkably well for a car of its size

So how did a car with such promise fail to set the world alight?

It all began with the Vision SLR concept, which first broke cover at the 1999 Detroit motor show… ‘Tomorrow’s Silver Arrow’ served three main purposes for Mercedes.

The first was to embody a new design language that could lead the firm into the new millennium, giving direction to the forthcoming R129 SL replacement, the R230, that arrived in 2001.

The second was as a testbed for new technologies, and the third was to form the basis of a new Benz supercar, the SLR.

The red leather adds a splash of colour, but the SLR doesn’t feel quite as special as some other supercars from the inside

In creating the Vision SLR, Mercedes stylists unashamedly looked to the past, mating design cues from the original 300SLR – campaigned so successfully throughout the ’50s by the likes of Fangio, Moss and Kling – with some cutting-edge technology developed from the firm’s F1 engine programme.

Externally, the Vision SLR concept’s lineage was clear to see, with its long bonnet and front overhang, straked side vents and curved rear end bringing to mind the original roadgoing 300SLR Coupé, not to mention its electrically operated 75º butterfly doors.

The low front spoiler with its twin ribs, meanwhile, echoed the McLaren-Mercedes Grand Prix cars that had just delivered Mika Häkkinen the 1998 F1 World Drivers’ Championship, and would do the same the following year.

The McLaren name added lustre, but the Mercedes-Benz SLR was far from the Woking firm’s F1 reborn

The concept’s 5.4-litre V8 engine was relatively conventional, borrowed as it was from the S-Class, but beneath the sloop-like bodywork lay a number of innovations that would go on to appear in both the R230 SL and the SLR.

The first to make the transition from concept to road car was the Vision’s trick electro-hydraulic braking, dubbed ‘Sensotronic Brake Control’ by the time it made full production in 2001.

Using a series of microcontrollers, the system precisely calculated the correct braking pressure for any given situation and offered exceptional stopping power thanks to fibre-reinforced ceramic discs capable of withstanding extreme heat.

The concept’s party piece, however, was without a doubt its chassis, which was constructed using fibre composites and aluminium, giving the car not only exceptional torsional rigidity, but also reduced weight – by as much as 40% compared to a conventional steel monocoque.

Gordon Murray at McLaren Cars was charged with taking the Vision SLR concept from motor show to showroom, but while the car was undeniably a technological tour de force, he quickly realised that it made much more sense as a design study than it did a prototype.

Murray’s original pitch to Mercedes had been for a rear-engined V8 supercar, and instead he found himself tasked with building a world-beater within the constraints of the original Vision design; it might have looked incredible, but was obviously more grand tourer than supercar.

The Mercedes-Benz SLR McLaren boasts a dizzying top speed in excess of 200mph

A team of just 36 created the McLaren F1 but, with the resources and backing of such a major manufacturer, 450 people were thrown at the SLR project.

They wasted no time in addressing the concept’s most obvious flaws, shifting the front-mounted V8 back in the chassis as far as was possible – 39.4in behind the front bumper and 19.7in aft of the axle line – and lowering the position of the fuel tank.

Murray had no control over the styling, but had always been a fan of active aerodynamics: the concept’s rounded tail was altered to be higher and flatter, increasing downforce, while an electronically activated spoiler was added that rose by 10º at 59mph, increasing downforce, and by 65º under heavy braking, reminiscent of the air brakes used on the original SLRs.

The underside of the car was also tweaked to give a flat underbody, with a purposeful, race-inspired rear diffuser.

The changes contributed to a weight distribution of 49:51 front to back but, though well balanced, the SLR tipped the scales at 1768kg – a far cry from the lightweight 1138kg McLaren F1.

The Vision’s chassis was carried over to the production model. At its core was a terrifically strong carbon-composite cell that surrounded its occupants, with carbon crumple zones both fore and aft – the first time this had ever been done in a series-production model.

Just like the ’50s 300SL, the Mercedes-Benz SLR McLaren Roadster (left) began production as the coupé’s slowed down

Usually hand-laid, the carbon process was modernised by McLaren with robots knitting, sewing, weaving and braiding the complex fibre structures at a purpose-built production facility in Woking.

Like the original SLR the new super-GT used an eight-cylinder powerplant, this time Mercedes’ familiar 5439cc all-alloy V8 mated to a five-speed automatic gearbox, though in the four years from concept to production power rose by some 69bhp.

Higher compression and a Lysholm-type twin-screw supercharger took the unit up to 626bhp – 1bhp shy of the McLaren F1, perhaps, but enough to comfortably exceed the performance expectations of the 1999 show car.

Despite its heft, the SLR could blast to 60mph in just 3.8 secs and carry on to a dizzying top speed in excess of 200mph.

The only way to truly understand the SLR’s performance is to test it away from public roads, so we arrive at the test track having driven ‘our’ black Roadster – the open version that arrived four years after the coupé original – cross-country from Historics Auctioneers.

Guy Tedder draws up in DD Classics’ silver tin-top, giving a chance to compare notes.

It quickly becomes clear that much more binds these two iterations than separates them; it’s like looking at a pair of twins who have outgrown their phase of dressing exactly alike.

The SLR’s supercharged V8 makes a thunderous 626bhp

Though they weren’t born at the same time, both were built at the same facility, with Roadster production beginning in 2007 as the coupé’s began to wind down.

Everything from the glass down is the same, from the frameless doors that hinge on the windscreen to the optional 19in turbine-style wheels.

The only visible difference is the soft-top, which unhooks manually before folding neatly into the rear shelf at the push of a button.

It’s a slick operator despite its inability to self-lock, with elbow grease apparently saving a precious 6kg.

Like its 300SL ancestor, both coupé and Roadster are impossible to enter while retaining your dignity. Paris Hilton managed it by virtue of being thinner than a spray-tanned toothpick, but for the rest of us climbing aboard remains a challenge.

In the end, you’ll probably settle on throwing yourself over the high sill arse-first and hoping the rest follows – something like a hermit crab retreating into his shell.

That achieved, the cabin is a pleasant place to be – if a little cramped for a car boasting such large external dimensions – and anyone who’s driven a contemporary SL will immediately feel at home.

With the same carbon tub as the coupé, the SLR Roadster offers a similar driving experience – albeit with an awful lot more wind in the hair

The carbonfibre buckets are fairly uncompromising, yet somehow manage to be comfortable at the same time, and the driving position is good, with a commanding view of the SLR’s intimidatingly long bonnet stretching out before you like the bow of a ship.

Inside, the two are almost indistinguishable, with the exception of the ‘Touchshift’ buttons for changing gear in the earlier car.

The roadster has conventional paddles, which prove much more intuitive when pressing on and easier to find if the wheel isn’t centred.

Hailing from a time when technology hadn’t quite kept step with designers’ ambitions, the SLR requires you to insert the ignition key before thumbing the starter, which is mounted on top of the gearlever beneath a flip-up cover.

It all seems a bit gimmicky until you try it for the first time: it’s near impossible not to imagine you’re firing the cannons of a fighter jet as the 90º V8 explodes into life with a menacing rumble.

The 5.4-litre mill doesn’t sound particularly tuneful, but there’s a definite appeal to its thuggish beat, even at idle. The twin side-exit exhausts sited just ahead of the doors – again bringing to mind the original SLR – contribute to the sense of theatre and give this aggressive GT the swagger of a cruiserweight boxer.

The SLR’s jewel-like LED tail-lights

Having both Roadster and coupé examples together is a rare treat, and perhaps the best way to witness the full-on aural assault of the SLR.

We stick to the Roadster and follow Tedder onto the circuit, easing past the coned pitlane before planting the throttle to give chase.

In an instant it’s clear that the SLR McLaren is going to be a handful, its cold tyres fishtailing on the damp road surface through the first bend.

It feels an order of magnitude faster than the 476bhp SL55 – more than could ever be exploited on public roads – so the track gives us a good chance to test its limits in relative safety (though the trees lining either side of the road offer a gentle reminder not to push your luck).

Kickdown is immense, provided you modulate the throttle slightly to keep the back end in check, and the SLR accelerates with unbelievable urgency.

It really is indecently quick, the sort of pace that raises the hairs on the back of your neck, but almost as intoxicating is the drama created by the thunderous exhausts and the insistent whine of the screaming 23,000rpm supercharger.

The SLR Roadster’s convertible roof works very well and seals to give an almost coupé-like feel

Devastatingly fast in a straight line, the SLR feels every bit an overpowered hot rod, yet it also behaves itself in corners, the conventional coil-sprung double wishbones working hard to keep the car’s bulk in check.

It performs admirably, with plenty of mechanical grip and – once you come to terms with the power delivery – a composed ride.

It’s only when you begin to get towards the limits that the SLR fails to inspire confidence.

The steering, which was understandably lifeless during our low-speed slog across west London, doesn’t improve quite enough at pace, feeling somewhat dull and disconnected from the road despite being heavy.

The brakes, which proved a squealing frustration at mundane speeds, come to life as they generate heat, but still leave you longing for slightly more reassuring pedal feel.

Conventional logic would have you assume that the open version of almost any car will be heavier, more flexible and less focused than its closed cousin, but only one of those statements holds true for the SLR. The soft-top is heavier, but only to the tune of 57kg.

The SLR Roadster (right) trumps the coupé, offering almost two cars in one

In every other regard there’s little compromise thanks to the use of the same carbon tub as the coupé, which makes it one of the stiffest road cars Mercedes has ever produced.

There’s practically nothing to choose between the pair in terms of performance, but the coupé is a more relaxed and refined place to be, the lack of buffeting encouraging greater speeds.

Raise the Roadster’s roof and the playing field levels once again; such is its quality that it’s almost as comfortable as the coupé.

As a result, the convertible wins the day: you essentially get two cars for the price of one.

The SLR might not have been exactly what Murray intended, and contemporary reviews weren’t as glowing as they could have been.

But time is the great healer, and with its passing what were once seen as flaws and compromises eventually turn into something much more valuable than impeccable handling or flawless aerodynamics: they become character.

And that is something the SLR has in spades.

Images: Will Williams

Thanks to: Historics Auctioneers and DD Classics

This was originally in our August 2019 magazine; all information was correct at the date of original publication

The Vision SLR concept was unveiled at the 1999 Detroit motor show

Gordon Murray on the ‘McMerc’

“We had a meeting with the board members, directors and senior people, and I said, ‘What is [the Vision SLR] supposed to be in competition with?’

“They replied, ‘Aston Martin, Ferrari, Lamborghini – all the top-end people.’

“And I said, ‘But it’s not a front-mid-engined car; it’s a front-engined car. It’s got no boot space, the fuel tank is high up above the back axle, it’s got these huge pneumatic suspension struts on each corner that weigh 9.5kg each, and I can see from here that the weight distribution is completely wrong. Forget it.’

“What I really wanted to say was, ‘I don’t want us to have our name on this car. It’s never going to handle, it’s never going to perform, and it certainly won’t be in competition with those guys you’ve just mentioned.’

“There was a lot of biting of tongues and gnashing of teeth, but they did come around and say, ‘OK, will you tell us what it has to be?’

“I went home and we did a little leaflet.”

The Mercedes-Benz Vision SLR makes little effort to disguise its 300SLR design cues

“It was a bit The cat sat on the mat! It said, ‘This is a sports car, this is a GT car and this is a saloon car. And a sports car must have this weight distribution.’ Stuff like that,” explains Murray.

“I said, ‘We’d love the job, but you’ll have to let us change the architecture completely and start again.’

“There was all sorts of really inventive stuff on the SLR. Engineering-wise, it was incredibly strong and rigid, and to this day I’m very proud of that structure.

“It was the safest car that Mercedes had ever made by a mile, and the stiffest car it had ever made by a mile, and probably still is to this day.

“It’s a significant motor car in my design career because it was for a big corporation where they let us do everything.

“I’m very proud of the engineering in it, but it’s not one I find endearing as a motor car.”

There are more of Murray’s reflections in his autobiography One Formula (ISBN 9781907085307).

Factfile

Mercedes-Benz SLR McLaren

Sold/number built 2003-2010/2282
Construction carbonfibre composite monocoque with carbon composite crash structures and aluminium subframes
Engine all-alloy, sohc-per-bank 5439cc V8, with screw-type supercharger and air/water intercooler
Max power 626bhp @ 6500rpm
Max torque 575lb ft @ 3250-5000rpm
Transmission five-speed automatic, RWD
Suspension independent, by double wishbones, coil springs, telescopic dampers; front anti-roll bar
Steering power-assisted rack and pinion
Brakes electro-hydraulic carbon-ceramic discs with anti-lock and brake assist; computer-controlled air brake
Length 15ft 3¼in (4656mm)
Width 6ft 3in (1905mm)
Height 4ft 1¾in (1261mm)
Wheelbase 8ft 10¼in (2700mm)
Weight 3890lb (1768kg)
0-60mph 3.8 secs
Top speed 207mph
Mpg 19.5
Price new Price new £300,000 (Roadster £350,000)
Price now Price now from £200,000*