As we came away from the eight days of testing, we saw the Ferrari was not only quickest on outright lap times, but looking finely-balanced through the turns. The Mercedes was slower, and appeared more difficult to drive.

The superficial conclusion was that Ferrari had got the new rules right and Mercedes were on the wrong path. Ferrari championship success was predicted, while Mercedes seemed to have finally reached the end of their streak of success.

That obviously isn’t how things have worked out. Had Max Verstappen not tagged Valtteri Bottas in the Monaco pits, Mercedes would probably be on a six-race streak of one-twos right now.

Why are Mercedes so much stronger than was widely expected, and Ferrari so much weaker? Closer inspection of those testing results and retrospection on recent race history indicates things weren’t as simple as they seemed a few months ago.

How testing gave a false impression

The dawn of 2019 saw major changes to several aspects of the car’s performance. These included simplified aerodynamic rules to aid overtaking and revised Pirelli tyres to cope with increased cornering loads.

Pre-season testing included runs on the new tyres in the hot weather in Abu Dhabi just after the last race, albeit without the new aero fitted to the cars. This was followed by a mere eight days over two weeks in the cool temperatures of Barcelona on the eve of the new season.

Ferrari hit the ground running. The car ran without any serious issues apparent. It was balanced through the long turns and consistently set the fastest times. And since then the aero set-up on the SF90 has changed little.

Mercedes turned up at testing with an interim aero set-up on the car in week one. The W10 looked a handful and its lap times weren’t encouraging. The media chatter was all around the silver cars’ apparent maladies.

For the second week Mercedes brought a wholly revised aero package. Some unrealistically suggested this was a response to their first week troubles. So rapid a response, taking just a few days, would have been impossible.

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The team’s technical director James Alison shed light on how the change of aerodynamic specification reflected the developments in the team’s thinking about its car.

“When we first put these new regulations on [the car], rules that have much, much less geometrical freedom, it haemorrhaged downforce off the car,” he explained. “When I say ‘haemorrhaged’, I mean about 2.5 seconds, gone!

“It was a big deal, so we started to understand what’s broken and why. All of the interface between the front wing endplate and flap was irredeemably knackered and the flow structures we had been developing had just collapsed.

“So we started working on it and we started to understand it and why won’t the air go where we want it to any more. We started to work on the geometries and start to persuade it back into order.”

That led the team to roll out a ‘base’ W10 for the launch run at Silverstone and the first four days in Spain, while the revised version benefited from greater development.

“Our first version, our launch car, you see our front wing endplate doesn’t even point outboard. It’s inboard because at the time we froze that car, that was the best we could do. That was restoring some the control we previously had outboard, restoring some of the load we previously had outboard, but we couldn’t yet expand it sideways without it falling off the wing.

And it took a few more weeks and months to learn how to do that.

“But once we had learned to do that, by and large, we had managed to maintain a lot of the power that we had in the tip of the wing that we had enjoyed previously.”

Analysis of the sector times around Barcelona showed some interesting variances between the two teams. Ferrari were clearly quicker in the first two sectors, and down the long straight, but not in the tighter turns of the third sector.

When the season opened in Melbourne, the sector times also reflected the strengths and weaknesses of the two cars. Only on Bahrain’s longer straights did Ferrari truly look fast.

At this point it still seemed Melbourne might have been a ‘blip’ and Ferrari would reassert themselves. But every circuit visited since has only reinforced the sensitivities of the two cars, the difference in the ‘whole weekend approach’ from both teams, and the relative weaknesses of the Ferrari design.

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The differences in Ferrari’s car concept

Ferrari have clearly aimed for a different car philosophy this season. One which on the face of it, or at least with the benefit of hindsight, seems counter-intuitive.

In a season where the DRS effect has increased due to the larger rear wings, and tyres modified to suit high cornering loads, the obvious solution would be a high-downforce and subsequently high-drag philosophy. Yet Ferrari purposely have gone the other direction, high top speed and lower cornering speed with a lower downforce/drag set up.

This assessment isn’t simply anecdotal, F1 supplies a comparative ranking of the car’s key performance indicators; these being top speed and a breakdown of three different cornering speeds (high, medium and low speeds). This routinely shows Ferrari topping the order on top speed, but less or equal to Mercedes on all the cornering rankings. The cornering analysis shows Ferrari worse off in slower corners. This data corresponds to what we know about the car’s hardware, with its PU, aero and suspension set-up.

In those first races we saw Ferrari’s speed on the straight outgun Mercedes, but how it achieved this was interesting. Looking at the acceleration traces from the FIA GPS, the Ferrari was matched on initial acceleration by the Mercedes. This first section of the graph showed that traction and shear engine power was a close match.

But then the Ferrari started to accelerate past the Mercedes, this transpired to be the MGU-K continuing to power the Ferrari all the way to the end of the straight, whereas Mercedes’ MGU-K ‘clips’ and relies solely on combustion power for the balance of the straight. Somehow Ferrari have found a way to drive the MGU-K for longer, most likely with the MGU-H harvesting energy from the turbo at full throttle, there being no limit to the amount of energy transferred via this route, although the MGU-K can give no more power than the 120kw (160hp) allowed in the regulations.

Ferrari were able to run relatively large rear wings despite this top speed variance, so some of the straight-line speed advantage is being eaten up by added downforce. This seems at first contradictory to the apparent low-drag philosophy of the 2019 Ferrari.

It may be that Ferrari have been surprised by their top speed advantage and lack of pace in the corners compared to Mercedes. Recouping this gap, Ferrari have been adding downforce with a bigger rear wing and more front wing angle, but this eats up the car’s aero efficiency, which goes against their base philosophy and probably eats fuel during the race too.

Ferrari have gone for a lighter base level of downforce. With this comes less drag too. The lower overall downforce level will hamper the car’s cornering in the medium-to-high-speed turns, as shown in the FIA data.

This goes further than the front wing philosophy, which gets the bulk of the attention. The SF90 sports an inboard-loaded front wing design, along with Sauber and Toro Rosso. The front wing is a key part of the car’s aero concept, but it’s only there to balance what aero load Ferrari are generating at the back of the car.

It’s the underfloor/diffuser area and ultimately the rear wing which sets the downforce level and, with that, the lift/drag efficiency too. It’s unlikely Ferrari found a front wing design and based the entire aero set up around it, rather it works the other way around. Indeed, the balance of the car through the corners is one of Ferrari’s better handling traits and proves the front wing is well matched to the rear end set up.

Then, the SF90 struggles the most in slow speed turns, this is a mix of downforce level and mechanical grip. Merely adding downforce will not cure the car of its ills through the slow stuff.

Ferrari have struggled with poor mechanical grip for many years. This seems to be a long-term Ferrari trait, dating back to the Michael Schumacher era and through the ‘front pull-rod’ period (albeit not related to the pull rod itself). Only in the past two years has the car’s front end come alive in slow turns, hence Raikkonen’s relatively stronger performance in those years.

Again, it’s easy to compare Ferrari’s suspension set-up to the Mercedes and see the obvious visual differences as the solution. Ferrari retain a conventional front suspension geometry, with relatively low-mounted wishbones which pass directly inside the wheel rim to the suspension upright. This gives a good kinematic geometry to the slight detriment of aerodynamic interference of the wishbones in the front wing’s wake. Not being far from last year’s design, there isn’t a fundamental reason for the geometry to be bad for tyre management.

The other aspect to the suspension performance is the compliance set-up, that being the springs and dampers working in heave, roll and over bumps. This area is shrouded in more mystery, no longer does an F1 just have metal springs and oil dampers to control the ride, as now there are hydraulically-operated units serving different functions.

These are not always visible inside the nose of the car, some elements may even be remotely mounted within the sidepod. Such is the complexity of this area the FIA struggle to understand the set-up from external examination. Such ‘hydraulic’ systems are a throwback to the front-rear inter-connected suspension era at the beginning of the decade when the front and rear suspension were connected. Even without any cross-linking, the current use of a hydraulically-activated remote spring to control pitch under braking and acceleration is a key area for performance, allowing better control of the tiny front ride height with the highly-raked nose-down set-up teams now run.

Media speculation that Ferrari do not have the same level of complexity in its ‘hydraulic’ compliance set up as its rivals is hard to confirm. Some reports suggest there is a system that has been tried this season that doesn’t work as expected, or a system run in 2018 that is still inferior to other teams. A lack of any such system being routinely run on the car is hard to believe, certainly an inferior system could be a pointer towards some of the teams struggles, but there’s no basis to doubt Ferrari’s expertise in this area.

The net effect is the Ferrari struggles to get the tyres working in the right temperature window, having been very easy on its tyres in recent years, which harmed it qualifying performance, but brought the closer to Mercedes in tyre limited race conditions. A lack of grip, either aero or mechanical, will see the car not put the lateral energy through the tyres to get them warmed up.

This year’s thinner gauge tyres and the stiffer sidewall construction have less internal movement in the tyre and less heat generated internally. Instead it’s the tread surface slipping on the track that generates heat, which sees a sudden ramp-up in tread temperature leading to problems which are then harder to control. This combined with the new restriction on the tyre-warming blanket temperature for the rear tyres means Ferrari simply aren’t getting the tyres up to the right temperature to get them to work.

This is especially hard in qualifying, and although the race situation is better they still face problems, not helped by the fact Mercedes usually have pole position and can then control the pace of the race to manage the tyres.

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Mercedes’ slow-corner advantage

Mercedes’ performance can be summarised as the inverse of Ferrari’s. The W10 is the datum for the FIA data, being fast in all types of corner, only lacking in straight line pace. As a result the car laps faster despite the comparative lack in top speed, due to its cornering speed advantage.

This marks a significant change in the five years since the V6 hybrid turbo power units were introduced. “In the early days of the power unit regulations change we had a car that was low-drag, fast on the straights, carried by the might of the engine. And over the years chassis and power unit have merged in order to extract the optimum lap time.

“Part of that was that the engine is still impressive, but we are able to wrap a chassis around it that has more downforce and more drag. We are not the quickest car any more on the straight. But we believe that the best compromise between these two main blocks of performance works well for us.”

Mercedes have also got the car working in the Pirelli operating range. Even with the thinner-gauge tyres generating less internal heat, Mercedes still struggle with race tyre condition, but having pole position, they are in a better position to manage the pace and tyres to suit their situation.

It’s this ‘whole weekend’ strategy that having a dominant position allows, Mercedes works the tyres harder, which is good for qualifying. Furthermore, qualifying allows DRS, so the top speed deficit is decreased, and the Mercedes power unit is probably the equal of Ferrari in its Q3 ‘party mode’. In the race the ability to keep the tyres in their working window is aided by the greater downforce levels and mechanical grip.

If Red Bull have set the bar for aero performance, Mercedes are a close match at worst. They are potentially even stronger, given their engine performance allows them to work the aero harder, trading horsepower for the drag created by greater downforce.

Likewise, with the suspension performance, Mercedes were quick to follow Renault’s initial lead in 2010, with ‘hydraulic’ elements leading to the FRIC systems. Even after these were banned the ‘hydraulic’ elements remain remotely mounted in the sidepods. These are hidden beneath carbon fibre covers, with just red and blue marked holes for the adjuster dials to be accessed, giving away the valves and accumulators’ position in the car.

Monaco gave rise to more speculation regarding Mercedes’ slow-corner suspension advantage. Again, this is a case of something existing being seen for the first time, leading to finger pointing as the ‘silver bullet’ solution.

With the front brake duct drums removed the pushrod mounting was fully exposed on-camera for the first time, even though the pushrod mount has been visibly protruding through the front brake duct all season long. For over a decade F1 designers have mounted the front pushrod on the swivelling upright, rather than the lower wishbone, a system known as pushrod-on-upright (POU). In this position the pushrod mounting can move with the steering.

If the mounting is in line with the outboard pivots for the upper and lower wishbone, then the steering has no effect on the pushrod. If it is offset then several different effects can be created, firstly you can create an ‘antiroll’ effect, the outer pushrod moves inwards to counteract the roll in the car as it steers. If you rearrange the POU geometry another way you can have both pushrods lower the car with steering. This is especially useful without FRIC, as the car pitches down under braking, improving the underbody aero, but then rebound upwards as the brakes are released. Having the car lower with steering keeps the front end low all the way through the corner, just when the aero effect is needed.

Teams have been exploiting this post-FRIC, but the FIA banned extreme geometries in 2017, where we were seeing huge POU offsets, with the mounting protruding through the brake duct. The technical directive called for just 5mm ride height change with 15 degrees of lock. Bearing in mind front ride height is less than 25mm, this was still a restriction.

Now Mercedes have been seen having ride height dropping with ‘full’ lock and the POU mounting exposed it’s clear that some of the effect of the TD has been overcome. Note the higher wishbone set-up of the Mercedes naturally places the POU mount further outboard, so care needs to be given in comparing its position relative to Ferrari.

On the PU side the Mercedes engine remains the bar to which other are compared, with Ferrari probably equal on peak power output, better with ERS deployment and less fuel efficient. One strong point of the Mercedes PU appears to the be the Internal Combustion Engine (ICE): sources suggest it can be pushed harder towards the fuel flow limit (as opposed the rev limit). Looking at the GPS traces the engine does not appear to accelerate any differently to Ferrari’s up to the point where the MGU-K clips on the straights, so the ICE doesn’t perform any better, but perhaps can do so for longer periods through the race. This may underline Mercedes stronger pace at critical periods through the race, whereas Ferrari may not have the same full power mileage available from their engine.

How Ferrari can respond

Its poignant that Matteo Binotto said before this weekend’s Canadian GP “We know we’re not competitive enough right now and, for the time being we haven’t got any more changes coming on the car that will have a significant effect on the problems we have encountered since the start of the season.” Indeed, the Ferrari has changed very little through the first six races.

At least Ferrari are admitting the problem, Binotto is unusually open for a Ferrari team principal, he admits the next steps call for change: “While we are developing our car step-by-step, now I think it’s time to question ourselves if we should look for different aero targets, how to achieve the final performance.”

Looking deeper he points towards the thermal tyre management as the symptom, he does not go as far as blaming the rubber. “The tyres of this season are quite different to the ones of last year. No blame, it’s only a matter of fact.

“The main difference is last year we had very good warm-up on the tyres and we are all focussed and concentrating on cooling the tyres as much as we can to keep them working because the lower was the temps, the better was the grip. The tyres of this season are quite different in this respect. Warm-up is a lot more difficult and what we may call the window, the temperature target by when you’ve got the best grip from the tyres itself, to achieve it you need to heat up the tyres. As well as cooling them down you need to heat them up.”

As the ex-technical director for Ferrari, Binotto understands the solution is complex and is subtly affected by all areas. “It’s an interaction of everything. What we are lacking is grip for the tyres because we are not able to make them work properly. And that’s an interaction between aero and mechanic. Overall, it’s a balance, how you may set up your car to be strong high speed and then you miss some balance and performance slow-speed. And if a car is well-balanced you’ve got performance both medium-high speed and low-speed. What we are lacking is the optimum in all the conditions.”

Specifically, he explains that downforce, how it’s created and at what road speed is a key factor. “Not only the downforce has absolute value but is how you may balance the downforce high speed to low speed. It may be as well how you may even target your aero development, efficiency versus maximum downforce itself.”

From this we can infer that Ferrari response will likely be largely seen as bodywork changes to add more downforce. This doesn’t mean that the front wing concept is fundamentally wrong, but in making more of the rear downforce, the front end may need to change to respond.

Likewise, with the suspension, Binotto is aware of the media claims of a special new ‘hydraulic’ set up, but feels Ferrari are in the ballpark in this area. “I think we’ve got what we’re looking for. But still we need to develop the car, we need to improve. There may be changes on the front suspension, yes, as we may change aero, as we may change cooling. But I don’t think that in the suspension itself there is something on the principle fully wrong.” Even if Ferrari do make changes in this area, be it geometry or compliance solutions, it’s unlikely we will be able to spot it.

Meanwhile Mercedes have a handsome lead in the championship, a new power unit expected for Canada, and no need to make obvious changes. Ferrari’s response is not just a case of salvaging what they can this year, and staving off the growing threat from Red Bull, but learning the necessary lessons to get their car concept right for the 2020 F1 season.

Quotes: Dieter Rencken

F1 technology