Ferrari SF-25

[venkyhere]

change in floor keel, looks narrower => more diffuser expansion

[Luscion]

List of upgrades for Bahrain

[zioture]

[zioture]

[zioture]

[ispano6]

[atanatizante]

Some new bits via Motorsportcom Italia.

They cut the brake fins fence:





They are trying to innovate here, placing a horizontally triangular flap on the diffuser kiel:





The front view of the new floor:

[ing.]

Thoughts on the function of the diffuser ‘flap’…

[zioture]

FP1

Ferrari testing a new rear wing in Jeddah!
Leclerc runs a modified DRS flap, trimmed for efficiency, while Hamilton sticks with the old spec.
Who made the right call?

[Owen.C93]

I’d be interested in any more images of the splitter. That lump is interesting. Do they run it in race trim? And is it sensing something?

[Farnborough]

Copied from team thread as I feel there's continuity and relevance here, not yet visible although speculative it does seem like something is coming to this car that may need keen eye to view for coming races.

With such extensive change it would seem there's fundamental issue that can't be "adjusted" out of to bring performance.

The good thing, if successful, is that recognition is there, with an outlook able to match and solve that.

Some things that lead my view on this:- they gave views of suspension spring stiffness which really are "bread & butter" itens in race team production abilities. They can easily make what they want at any rate they need. There's been discussion of softer springs and different bellcrank curve for CL and appear to hold the advantage over LH in absolute pace, which to me suggests that there exists a basic core structural integrity / level problem within tub & gearbox stressed structures.
If the spring rates are simply ramped up in attempt to concisely control travel (height and hitting the track as evidence) then to ultimately fail, suggest the spring "grouping" is stiffer than the structure supporting it. Tbat gets them into a setting "loop" that looks to invert any gain they are attempting to achieve.

There has been rumour about gearbox integrity from the start and coming from Bahrain. The "box" itself is normally a unit containing the gear and diff etc as one piece, this "housed" in an outer casing exoskeleton unit (the part we see in build images) to take all if chassis load. This also ultimately structured to facilitate wing mount and rear crash structure architecture. If that component has to be changed, then crash test etc would logically be part of the development to sign off. Its not a short timescale for this being a more fundamental part of chassis layed down early in development.

This would highly likely feed into next year, at least in effectiveness terms. If no way of getting around it now, they've got to jump into it anyway.

If they have either undershot the torsional performance through design OR in build, there's no real answer but to change this.

You can get, multi rated suspension in rising rate, non linear, progressive, regressive, all three type within one suspension stroke at different points of movement, end stroke support "platform" damping shift, along with geometry shift ..... just in a DH bicycle rear suspension system. Just an illustration of what is possible in fairly mundane and relatively inexpensive system in general market. These F1 engineer team have far, far more information and support to enact their systems into chassis. If they can't do that, it seems to confirm some level of basic structure compromise exists in preventing that undoubted knowledge being used to correct this car.

Something fundamental in there is wrong.

Ordinarily, to run lower a stiffer spring rate would be used, set then to lower static height (the situation they acknowledge doesn't work) but keep needing to "jack" it in preventing ground strike demonstrating loss of control, or more correctly the opposite outcome from their changes. Torsional performance of chassis in lacking, classical in this type of response, never resolving, failing to "play" to book as logical adjustment is made.

It's not without that in history though, the previous SF seemed likely in the same area, with exclusion also caused by plank wear at COTA and when running competitive pace. Also characteristic in all of these lineage from 2022 being notably fickle since 2022. The TD 039 APPEARED to take away a floor flexing "loophole" that would have masked this aspect.

Monaco wouldn't necessarily punished this if true not all races the plank would have been checked either.

Something in the core design is lacking, finding it now MUST take precedent for everything this team wants to achieve.

[Vanja #66]

Full deep dive on rear end issues



The main thing:

Ferrari 2022 car was a well-defined concept designed for and according to original 2022 rules, before TD39 and 2023 floor changes were introduced

A big part of that concept was a tight engine cover and a tight rear coke-bottle area, both of which were made possible by keeping rear pull-rod suspension used on most pre-2021 cars

When VF-22 was destroyed in 2022 Monaco GP, we could see how Ferrari's 2022 gearbox was packaged. There wasn't a lot of room for mechanical components, as the crank shaft of ICE needs to go into the gearbox right through this complex mechanical system



In 2023 there weren't big changes to this system, while SF-24 got an update and this meant a change in internal suspension geometry, as well as shorter and tighter gearbox

This solution was working very well - for about 8-9 races. In Barcelona 2024, Ferrari brought an aero update package that reintroduced the dreaded high-speed bouncing. The problem was believed to be purely aerodynamic in its nature - but it never really is. Bouncing has to be solved tailored aero-mechanical setup solution

Ferrari worked mostly on the aero side and fully cured this issue with Monza 2024 package. Believing they found the right path for rear end floor development, they were fully committed to an already well-defined rear-end suspension solution within the gearbox casing for their 2025 car



At this point, it's worth reminding ourselves of the mechanical update Mercedes brought in Monaco 2024, with a big bulge appearing over front suspension mounting points

Mercedes brought a new front wing as well as redesigned front suspension components, including new damper assembly (revealed on photos in later events only) which apparently solved a lot of front-end issues they had

This damper was quite large in diameter, and this is important because damper and Belleville Spring characteristics depend a lot on their diameter - especially when you need to tailor their non-linear characteristic to specific circuit needs for every race track





Finally - putting 2 and 2 together, did Ferrari leave the gearbox case too small for the loads the cars generate in 2025? Are they now limited to rear-end damper diameter they can place?

This would explain a lot of things, especially taking into account an unplanned departure of early-season Technical Director from Ferrari in 2024. Former TD put the early concept of SF25 in place and was overseeing the design and target limits for the whole car, before deciding to take the offer from AMR

The chaos that happened in early races this year was caused by sudden realisation of massive mistakes in early design process. Gearbox and Chassis are two systems with long lead-times, so they are defined first and development is frozen very early - sometimes even in October for next year's car. By the time they are frozen, the actual design is finished for some time and final calculations and simulations are taking place to verify if this design reached its targets



What can Ferrari do now?

The redesigned rear end mechanics have been confirmed by Auto_Racer_it team and updates are in development. Whether they are introduced at Silverstone is another question. What the team might be focusing on is

redesigning the entire Gearbox Case to accommodate larger rear suspension mechanics or
redesign the rear suspension mechanics within the limits of current GB Case

First solution is probably better, but a lot more time and budget consuming. Is this worth the risk? I have no idea, but it's worth remembering the rear crash structure needs homologation with crash-testing and this means even more time and money is needed

The 2nd solution is aimed at taking a very different approach to suspension mechanics most likely, while working around the potential core problem

If successful, the 2nd solution would be very cost and time efficient considering the problem the team now has - running the car higher than optimal and using compromised setups to try and keep the tyres in the right window despite having less downforce

If the solution is not successful - it's the final year of this regulation set and valuable points in Title Chase are already lost...

[Emag]

* cut for better readability

Okay, this is a fantastic and incredibly detailed technical breakdown. Particularly interesting is the retrospective on the Mercedes 2024 Monaco package, which as you point out, had a very significant mechanical component which was often overlooked, with the front wing making most of the headlines. However, considering the rather significant turn for the better that Mercedes took after Monaco when it comes to their performance, it was hard to believe the flexing front wing alone was the culprit behind such a turnaround.

Now this is rather important for Ferrari, because after reading your analysis, it really got me thinking about the importance of the mechanical platform. The timeline you laid out, with the initial success of the SF-24's updated gearbox and then the re-emergence of bouncing post-Barcelona 2024 update, is crucial. It makes me wonder if the Monza 2024 package, while appearing to "fully cure" the issue, was perhaps an aerodynamic workaround that brought the car into a more compliant window but didn't address an underlying mechanical limitation. If the 2025 car is targeting even higher aerodynamic loads, as one would expect, it could be that this previously masked limitation, the potentially undersized damper capacity due to gearbox casing constraints, is now being exposed to a greater capacity with the grid taking their respective concepts to the extreme.

Long story short, it's a really cool subject that you've dissected brilliantly. It’s a complex situation for Ferrari, and your explanation of how they might have arrived here is one of the most convincing I've seen. The implications are not great for Ferrari, but as we know, F1 engineers are some of the best in the world at solving difficult problems. If this is indeed the core issue, their response will be a testament to their capabilities. The fact that this is the longest season in F1 is some saving grace for Ferrari. The car has shown great potential those few cases it was running optimally, so they might still yet have time to turn things around.

Cheers for the excellent write-up!

[venkyhere]

So Vanja, the 'layman-level' short summary of your very detailed post is :

"rear suspension stiffness is limited by too tight packaging, which limits putting a large damper to help stiffen up the rebound, thus leaving the car with a softer-than-optimal suspension which indirectly forces the front suspension to be softer as well, inorder to not lose mechanical balance"

Did I understand right ?
If yes, I circle back to the controversial post I made a few pages back (not sure whether in this car thread or the team thread) - what drove the creation of a shorter and tighter gearbox ? The need to 'push the driver back' ? Where did that need come from ? Was it purely an engineering choice ? I know I drew a lot of flak for asking this before, but I dare ask once again now.

[Vanja #66]

Now this is rather important for Ferrari, because after reading your analysis, it really got me thinking about the importance of the mechanical platform. The timeline you laid out, with the initial success of the SF-24's updated gearbox and then the re-emergence of bouncing post-Barcelona 2024 update, is crucial. It makes me wonder if the Monza 2024 package, while appearing to "fully cure" the issue, was perhaps an aerodynamic workaround that brought the car into a more compliant window but didn't address an underlying mechanical limitation. If the 2025 car is targeting even higher aerodynamic loads, as one would expect, it could be that this previously masked limitation, the potentially undersized damper capacity due to gearbox casing constraints, is now being exposed to a greater capacity with the grid taking their respective concepts to the extreme.

Cheers mate, glad you liked it and agree!

Yes, I was also pointing out that suspension is likely unable to absorb the loads and provide adequate damping last year during Barcelona fiasco revelation. Everyone was 100% convinced it was an aero issue, yet just because it was solved with aero updates later - doesn't mean it couldn't have been solved through suspension update as well

Apparently, even now in GES they believe they can solve a part of their issues with aero updates and it may be needed if they can't fully support their current target aero map

So Vanja, the 'layman-level' short summary of your very detailed post is :

"rear suspension stiffness is limited by too tight packaging, which limits putting a large damper to help stiffen up the rebound, thus leaving the car with a softer-than-optimal suspension which indirectly forces the front suspension to be softer as well, inorder to not lose mechanical balance"

Did I understand right ?
If yes, I circle back to the controversial post I made a few pages back (not sure whether in this car thread or the team thread) - what drove the creation of a shorter and tighter gearbox ? The need to 'push the driver back' ? Where did that need come from ? Was it purely an engineering choice ? I know I drew a lot of flak for asking this before, but I dare ask once again now.

Yes, this is my view based one everything we've heard and seen so far. I was actually 99% sure of it in early April but it would have been too far fetched without the leaks and inside info we got lately.

The shorter gearbox and repositioned elements along the X axis (longitudinally) were driven by aero requirements to reduce drag and increase downforce. By moving sidepod inlets more to the back, you cut down on their drag significantly because you can have the sides generate less pressurisation to generate outwash of front tyre wake

The car actually has CoG more on the nose than SF24, even with WB extended by 25mm. This is achieved with lots of ballast in the front wing tip