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The formula for a sustainable supercar business: Create a hugely powerful, aspirational coupe with a hint of history and tradition, produce it in limited numbers, and if interest is sufficient, introduce a convertible version to satisfy demand.
That is precisely the route McLaren has followed with its highly potent 765LT coupe, released only last year, culminating in the 765LT Spider – the most powerful convertible supercar ever from Woking, and the latest and most engaging addition to the brand’s Longtail lineage. Only 765 of the recently unveiled Spider will be built to customer order – the same total as the sold-out coupe.
The Spider inherits the immense performance and dynamic prowess of the 765LT coupe, yet according to McLaren it is enhanced by three factors: the stability of its MonoCage II-S structure, the design of its one-piece Retractable Hard Top roof, and the ongoing pursuit of the company’s philosophy of super-lightweight engineering.
The Spider version of the carbon fibre MonoCage II – designated MonoCage II-S – was developed alongside the coupe monocoque and shares most of its structural elements, including the windscreen surround. Carrying over the dynamic and aerodynamic DNA of the coupe means the 765LT Spider weighs only 49 kg more – primarily from the retractable hard top and accompanying operating mechanism.
At 1,388kg the 765LT Spider is 80kg lighter than a 720S Spider and about 100kg lighter than its closest comparable competitor, yet the structure is so strong and stiff that no additional bracing was required over the coupe – a further weight-optimising factor – and at the rear of the car the carbon fibre structural supports are fully bonded into the chassis to provide rollover protection.
Ultra-lightweight
Other weight-saving measures include a thinner windscreen and side windows, a new lithium-ion battery (3 kg lighter), the titanium exhaust system (at 10.9kg it weighs 40% less than a stainless steel system), Formula 1-spec 20NiCh nickel chrome for the pinion and crown wheel inside the transmission final drive, and ‘helper’ springs for the lightweight spring system.
The bespoke front splitter, new front bumper, lower door blades and side skirts, wraparound rear bumper and active rear wing are all made of carbon fibre, while the light aluminium bonnet, front fenders, outer door panels and rear fenders are also available in body-colour carbon fibre as MSO Defined options – reducing weight by another 6.1 kg.
The LT’s lightweight 10-spoke alloy wheels (fitted with Pirelli P Zero Trofeo R tyres) slashes another 22kg, while inside the cockpit the race seats are together 18kg lighter than the 720S sports seats. The central tunnel is made of 0.9mm thick carbon fibre and another 14 kg is saved by deleting the floor carpets, air-con and audio system – although the latter two can be ordered as no-cost options. For owners who want to go even further, super-lightweight carbon fibre race seats (each seat shell weighing only 3.35 kg) can be fitted.
The electric, one-piece carbon fibre Retractable Hard Top (RHT) opens in just 11 seconds and operates at speeds of up to 50km/h. The roof design plays an integral role in the structure, as the frame within the hard top creates a full carbon fibre shell when closed. The panel is also significantly longer than its 675LT predecessor, allowing the tops of the A-pillars to be moved forward by 80 mm, increasing the size of the door opening for ease of access.
Ferocious performance
Even with the roof in position, the electrically-operated rear window in the RHT allows the dramatic, searing “LT soundtrack” from the quad-pipe titanium exhaust system into the cabin – taking open-air driving pleasure and driver engagement to another level.
As expected, performance is ferocious, and the M840T 4.0-litre twin-turbo V8 engine, producing 563 kW at 7 500 r/min and 800 Nm of torque at 5 500 r/min, gives the 765LT Spider a best-in-class power-to-weight ratio of 440 kW-per-tonne at lightest dry weight.
With revised ratios in the seven-speed SSG transmission (with Comfort, Sport and Track modes), in-gear acceleration is 15% quicker than a 720S Spider, making the new LT Spider the fastest ever McLaren convertible model – sprinting from 0-100 km/h in 2.8 seconds, from 0-200 km/h in 7.2 seconds, covering 400 m in 10 seconds and reaching a maximum speed of 330km/h.
The 765LT Spider has the same aerodynamic package as the coupe (with class-leading downforce 25% greater than that of a 720S Spider) but the active rear wing calibration has been revised for aero differences when the roof is up or down. Its doors (with no upper carbon fibre frame) are smaller and lighter than the coupe’s and extend further (by 120 mm each side) – the only difference in dimensions between the two models.
The Spider shares the enhanced chassis dynamics of the coupe, with bespoke LT springs and dampers, increased front track width, lower front ride height and unique software programming for linked-hydraulic Proactive Chassis Control II suspension. However, the dampers are recalibrated to account for the minor increase in weight.
Inside, differences between coupe and Spider are minimal, with the latter’s cabin having an extra element of carbon fibre upper trim. The coupe’s engine window also makes way for the Spider’s folding roof mechanism, and there are two MSO Defined packs available for the LT Spider – the Clubsport Pack and the LT Black Pack that reduces overall weight and increases circuit performance.
Last word
Like its predecessors, the new 765LT Spider stays true to the Longtail principles, placing the driver at the centre of the sensory, dynamic and aural experience, with the added dimension of theatre and drama offered by the convertible roof making it an even more immersive and compelling car to drive…
With pricing starting from R6,380,000 (at current exchange rates) the LT Spider can now be ordered from McLaren retailers but with only 765 available for customer orders worldwide and this year’s production already sold out, you will need to move quickly if you want one…
Report by Ferdi de Vos| Images © McLaren Automotive
