Ducati Streetfighter V4 S

From a press release issued by Ducati:

For 2021 Ducati presents the Streetfighter V4 S in a new Dark Stealth colour scheme, which joins the sporty Ducati Red. Furthermore, all models in the Ducati Streetfighter V4 range become compliant with the Euro 5 anti-pollution legislation (Only for Markets where EU 5 is applied).

The Streetfighter is the result of the “Fight Formula”: the Panigale V4 stripped of the fairings, with a high and wide handlebar, 178 kg on the scale, powered by 1100 cc Desmosedici Stradale delivering 208 hp kept in hand by biplane wings and a complete electronic package.

There are a multitude of engineering and technological aspects conceived for this champion road bike. A balance of distinctive lines, brutal output, state-of-the-art technology and components have been combined in this “Fight Formula” of the Streetfighter V4.

Euro 5 engine

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.

All Streetfighter V4 models in the 2021 range are fitted with new front brake and clutch pumps, both self-bleeding and derived from those used for the first time on the Superleggera V4. The body of the new pumps has been designed with a configuration that allows a ‘natural’ bleeding, thus eliminating the need to intervene on the system in the event of air present in the circuit.

MotoGP-derived engine

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.

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°.

Integration of engine and chassis

The optimal integration of engine and chassis is a fundamental concept behind every Ducati project. That is why the Desmosedici Stradale was developed to be mounted rotated backwards by 42°, like the Ducati MotoGP engines, to optimise weight distribution, use more extensive radiators and to shift the swinging arm pivot forwards as much as possible.

The Desmosedici Stradale was also designed to be a structural element of the frame. Connections to the main frame were added to the front of the upper casing and in the head of the rear bank. The engine block also acts as a connection for the rear suspension and swinging arm.

Compactness

Compared to a classic in-line four-cylinder, the lateral compactness of the V-engine allows greater centralisation of the masses and makes it possible to limit the weight on the front end of the bike. Furthermore, the shorter crankshaft generates a smaller gyroscopic effect.

All these aspects have a positive impact on the bike's dynamics, helping to make it light and fast when changing directions. The large space available between the V of the cylinders made it possible to position the water pump and have a large volume airbox (12.8 litres) to allow the Desmosedici Stradale to breathe better.

Chasis and Ergonomics

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.

Front Frame

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.

Sophisticated suspension

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).

Wheels and tires

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

The rims mount Pirelli Diablo Rosso Corsa II tires. 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 tires in the FIM Superbike World Championship.

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

Braking system with Brembo Stylema calipers

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

Brembo double calipers 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 EVO 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.

Racing tank

As on racing bikes, the 16-litre aluminium tank has a section that extends under the seat. Compared to the Panigale V4, the lower section of the tank has been modified to allow installation of a seat with thicker padding to boost rider comfort.

Up front, the space not occupied by fuel has been used to house all the electronics, battery included.

MotoGP-derived electronics

The latest-generation electronics package on the Streetfighter V4 is based on a 6-axis Inertial Measurement Unit (6D IMU) which instantly detects the bike's roll, yaw and pitch angles.

The electronics package has controls for every part of the ride: some oversee start, acceleration and braking, others govern traction and others again lend a helping hand on corners and out-of-the-corner stretches.

ABS Cornering EVO
Ducati Traction Control (DTC) EVO 2
Ducati Slide Control (DSC)
Ducati Wheelie Control (DWC) EVO
Ducati Power Launch (DPL)
Ducati Quick Shift up/down (DQS) EVO 2
Engine Brake Control (EBC) EVO
Ducati Electronic Suspension (DES) EVO

Operational parameters for each of these controls are associated by default with the three Streetfighter V4 Riding Modes. Riders can personalise parameters to suit their riding style or restore Ducati factory settings. DTC, DWC, DSC or EBC control levels can be adjusted quickly via the left switchgear.

Second-generation TFT instrumentation

The Streetfighter V4 features the same 5" full-TFT high resolution colour screen (186.59 PPI - 800xRGBx480) as the Panigale V4. The dashboard is dominated by the round virtual rev counter on the right. Desmosedici Stradale revs are displayed on a needle gauge.

Movement of the latter is accompanied by a white trail that acts as a 'shift light', changing colour from white to orange and then red as the rev limit approaches.

The rider can call up two different lay-outs: 'Track' highlights the lap times and the rev counter scale makes the revs typical of track use more clearly visible; 'Road', instead, replaces lap times with info on the Ducati Multimedia System (DMS), where present, and the rev scale is more appropriate for road use.

Complete titanium exhaust assembly

Made exclusively by Akrapovič with the Ducati experience. It is the most advanced racing assembly available on the market.

Each section of the system is manufactured in a special titanium alloy that is both lightweight and resistant to high temperatures, allowing for an overall reduction in the bike's weight. Once installed on the bike, the exhaust dramatically increases the already excellent weight-topower ratio of the Panigale, for breathtaking accelerations and stretches.

Thanks to its experience in the races has developed the qualities of the motorcycle and exhaust to their maximum levels to create a perfect synergy, specifically for this exhaust, recalibrating the many and fundamental electronic aids: DTC, DWC, DPL and Slide on demand.

Dry clutch kit

Just like in MotoGP, where the only thing that matters is utmost performance, the dry clutch is made available for the new Streetfighter V4.

This is an STM EVO-SBK clutch made from billet aluminium with housing and 48-tooth plate pack. The plates are 9 driven and 9 lined with a diameter of 138 mm.When racing on the track there are important benefits in ease of handling.

Specifically, the dry clutch ensures a more effective slipper function, even during the most aggressive downshifts, and greater fluidity during all "off-throttle" stages. In addition, the "mechanical" engine brake level can be customised by choosing a different secondary spring from those available from the catalogue.Other important advantages are the absence of resistance from the engine oil and cleaner oil since the plate wear dust is not conveyed into the lubrication circuit.

The racing character of the dry clutch is an exciting added benefit for the most passionate Ducatistas.

Dry clutch cover

Designed to offer optimum ventilation of the dry clutch during track use, enhancing its characteristic sound. The lightness and strength of the carbon fibre combine with the race-ready look in an accessory that has a uniquely sporty DNA.

Magnesium rims

The unmatched lightweight performance of forged magnesium meets style – a signature 9-spoke design that combines class, high performance and weight saving. This set of rims is approved for single-seat use only.

Adjustable rider footpegs in aluminum

Developed thanks to the experience of Rizoma. Made of high quality anodised aluminum alloy that maintains its original appearance over time.

Adjustable in six positions, they allow the rider to find the position that best suits their build and riding style. Equipped with fold-away brake and gearchange pedals to minimise the risk of breakage in the event of a slip.

They use the standard DQS, which can be configured both as a traditional shift and as a reversed/racing shift. An essential accessory for the most demanding riders.

Racing pair of handgrips

Inspired by the racing world, these handgrips ensure an excellent grip in every riding situation. Built to avoid accidental slipping of the hand and to reduce the vibrations felt.

Carbon tank cover

A splendid detail that embellishes the front of the Streetfighter V4 tank in a way that only carbon fiber can. The finishing and lines of this accessory are perfectly integrated into the racing look of the latest bike made at Borgo Panigale.