Fast, agile mixed-road performance demands maximum stability at high speed and when braking, reduced wheel-up during acceleration and minimised electronic control of the suspension set-up: that’s why Ducati Corse specialists have, together with the Ducati Style Centre, developed biplane wings for the Streetfighter V4.

The aerodynamics were developed using CFD (Computational Fluid Dynamics) simulation. The calculation method involved stationary simulation of flow and pressure to achieve increased downforce, especially on the front wheel.

To reduce lateral protrusion as much as possible, the aerodynamics team decided to adopt a ‘biplane’ configuration of limited ‘wingspan’ with upper and lower wings working independently.

Each appendage can be described as a square-plan mono-wing with a winglet on its outer tip. Moreover, the wings have been positioned as close as possible to the front wheel (near the radiator side panels) to maximise the anti wheel-up effect.

These aerodynamic appendages generate 28 kg of downforce at 270 kph (20 kg on the front wheel, 8 kg on the rear). The wings also help draw heat off the engine by increasing water and oil radiator throughflow speeds by 2% and 10% respectively.

Wing-generated downforce attenuates front wheel ‘floating’ at high speed and the tendency to wheel-up. It also improves stability during braking at the turn-in point and through the corner.

The aerodynamics thus instil confidence and limit intervention by electronic controls. This helps the rider keep the throttle open longer and brake later going into the bends, providing significant performance benefits.

With the arrival of 2021, all the bikes in the Ducati Streetfighter V4 range become compliant with the Euro 5 anti-pollution regulations, keeping the maximum power and torque values unchanged, but repositioned at different speeds.

The Streetfighter V4 Euro 5 delivers 208 HP (153 kW) at 13,000 rpm (250 rpm higher than the EURO 4 version) and a torque of 12.5 Kgm (123 Nm) at 9,500 rpm (2,000 rpm lower than the EURO 4 version). These values, obtained thanks to a new calibration and the new exhaust, make the bike even more enjoyable on the roads all curves

The silencer, unchanged from an aesthetic point of view, uses oversized catalysts (+10 mm in length) and a new technology of insertion of noble metals, essential to maximize the ability to convert polluting gases.

Compared with the Euro 4 models, the rear bank manifolds have been shortened by 100 mm and reduced in diameter from Ø 42 mm to Ø 38 mm. The new component has allowed the introduction of a more compact rear heat shield integrated in the body of the motorcycle.

Also in favor of reducing emissions, the introduction of 4 lambda sensors, one for each cylinder, which allow a more refined control of the quantity of fuel injected.

The Desmosedici Stradale was designed around the heart of the MotoGP V4 engine – its cylinder heads.

The fluid dynamics concept of the Desmosedici Stradale is based on the dimensions and geometry used in the Desmosedici GP bike, as is the engine layout: 90° V4 banked rearward 42°. This solution makes the engine extremely compact, allowing the centring of the masses and better integration into the bike.

The 81 mm bore is the same as that used on the Desmosedici GP, the maximum size allowed by MotoGP regulations, and is the largest in the Supersport 4-cylinder segment. The 53.5 mm stroke is longer than the GP engine, to provide increased torque when used on the road, and reduce maximum engine rotation speed. The use of the same bore as the Desmosedici GP engine means that all the fluid dynamics, which in fact make up the heart of the engine, are also very similar in the two drive units.

The V4 90° layout makes the engine extremely compact, allowing the centring of the masses and better integration into the bike. In fact, the Desmosedici Stradale has been inserted into the vehicle with the front bank of the cylinders rotated back by 42° with respect to the horizontal plane, as on the Ducati engines competing in MotoGP.

This optimises the distribution of weight, allows for the use of more extensive radiators and makes it possible to shift the swinging arm pivot forwards. Its architecture also generates a natural balancing of first-order forces, without the gain in weight and loss of power of a balance shaft.

Valve play adjustment (Desmo Service) is required every 24,000 km; services are performed every 12,000 km/12 months.

Air intake is entrusted to four oval throttle bodies (52 mm diameter equivalent) connected to fixed 70 mm long intake horns. Each throttle body has two injectors: a sub-butterfly one for low-load use and another above it that comes into play when maximum engine performance is required. The throttle bodies of each cylinder bank are moved by a dedicated electric motor.

Thanks to the full Ride by Wire system, this allows complex electronic control strategies and modulation of engine ‘feel’ according to selected riding mode.

To increase urban riding comfort the rear cylinder bank is deactivated at idle when water temperature exceeds 75°.

Compared to the Panigale V4, the riding position – with an above-ground height of 845 mm – has been redefined as per the specifications of a naked model. In keeping with streetfighter culture, the semi-handlebars have been replaced by a high, wide bar that, together with a seat with 60 mm of foam thikness and moderated footpeg position, ensures sports-style comfort during inner city rides and the control needed to tackle country roads or racetracks.

While maintaining many of the Panigale’s stylistic features, the tail is supported by a steel subframe and has been redesigned to enhance passenger comfort and give the rider more lengthways space.

The Streetfighter V4 features the Front-Frame – an offshoot of Ducati’s extensive experience in MotoGP – which uses the Desmosedici Stradale engine as a load-bearing member.

Compared to traditional perimeter frames the main lay-out difference is that the engine is used as a structural chassis element. Weighing just 4 kg, the compact Front-Frame is attached directly to the upper crankcase of the front cylinder bank and the cylinder head of the rear bank; the V4 crankcase also provides the rear suspension attachment point and the single-sided swingarm pivot mount.

The key advantage of the Ducati Front-Frame is that it uses the Desmosedici Stradale engine to achieve the desired stiffness: this has resulted in significantly lower main frame length and weight and a better stiffness/weight ratio. Moreover, the struts alongside the engine have been shortened, making bike design more compact, especially in the rider’s seat area.

Completing the chassis is the under-seat Trellis subframe, attached to the Front-Frame at the top and bolted to the head of the rear cylinder bank below.

The rear suspension linkage mechanism is attached to the Desmosedici Stradale engine via a forged aluminium bracket. The linkage reacts to movements imparted by a cast aluminium high-truss swingarm.

Steering geometry features a 24.5° rake and 100 mm trail.

The Streetfighter V4 mounts 43 mm Showa Big Piston Forks (BPF) to provide full adjustability in spring pre-load and compression and rebound damping.

The fork bodies house chrome sliders with Brembo radial caliper mountings. A Sachs steering damper completes the front-end package. At the rear there is a fully adjustable Sachs shock absorber, one side of which is attached to the Desmosedici Stradale engine via a forged aluminium bracket.

The Streetfighter V4 S, instead, is equipped with an Öhlins NIX-30 fork, an Öhlins TTX36 rear shock absorber and an Öhlins event-based steering damper. On this version suspension and steering damper are controlled by the second-generation Öhlins Smart EC 2.0 system which, among other things, features the new OBTi (Objective Based Tuning Interface).

While the Streetfighter V4 mounts cast aluminium 5-spoke wheels, the V4 S is equipped with 3-spoke Marchesini forged aluminium alloy wheels.

The rims mount Pirelli Diablo Rosso Corsa II tyres. Combining track performance with road versatility, they come in the 120/70 ZR17 (front) and 200/60 ZR 17 (rear) sizes, already used extensively for slick tyres in the FIM Superbike World Championship.

The rear tyre compound has been designed by Pirelli specifically for the Streetfighter V4. It ensures the same dynamic behaviour as the Supercorsa SP race replica tyres mounted on the Panigale V4, but has better low temperature performance to ensure the versatility one expects from a naked.

The StreetFighter V4 range incorporates the powerful Brembo Stylema® monobloc callipers that represent the evolution of the already high performance M50 callipers.

Brembo double callipers have four 30 mm diameter pistons each and work on 330 mm diameter discs for an unparalleled braking power. Whilst the rear system incorporates a single 245 mm disc with a 2-piston calliper. The braking system is supported by the ABS Cornering system, which uses the lightweight 9.1MP control unit.

With the MY2021, new front brake pumps and a self-purging clutch have also been introduced, both originating from those used for the first time on the Superleggera V4. The new pump unit has been designed with a unique configuration to allow “natural” purging, hence eliminating the need to intervene on the system if any air gets into the circuit.