Ferrari has triggered a controversy over high-tech suspension systems on the eve of the 2017 season after lodging a complaint to the FIA about technology pioneered by Mercedes.
Mercedes ran a fully-legal hydraulic system last season to improve the overall stability of the chassis, as a way to circumvent the banning of Front and Rear Interconnected (FRIC) suspensions in 2014. This was achieved by placing a heave behind the rocker assembly to control vertical displacement of the suspension, helping its drivers be more aggressive under braking and with kerbs, while also aiding tyre management.
That concept helped Mercedes stay ahead of its rivals last year, while Red Bull also made big gains over the course of 2016 by exploiting similar concepts with the RB12's radical rake angles. To query the use of such systems for the coming season, Ferrari has written to the FIA -- which is common practice among every team when it comes to the interpretation of rules -- to determine whether the concepts are legal.
Ferrari's letter has asked whether a system which would replicate FRIC without a physical connection between the front and rear of the car -- similar to the Mercedes concept in question -- would be accepted under the regulations. Article 3.15 of the F1 regulations states that "any specific part of the car influencing its aerodynamic performance must remain immobile in relation to the sprung part of the car" -- effectively banning moveable aerodynamic devices.
As reported by Motorsport.com, chief designer Simone Resta wrote in a letter circulated to all the teams: "We are considering a family of suspension devices that we believe could offer a performance improvement through a response that is a more complex function of the load at the wheels than would be obtained through a simple combination of springs, dampers and inerters.
"In all cases they would be installed between some combination of the sprung part of the car and the two suspension rockers on a single axle, and achieve an effect similar to that of a FRIC system (Front Rear InterConnected suspension) without requiring any connection between the front and rear of the car.
"All suspension devices in question feature a moveable spring seat and they use energy recovered from wheel loads and displacements to alter the position of the heave spring. Their contribution to the primary purpose of the sprung suspension -- the attachment of the wheels to the car in a manner which isolates the sprung part from road disturbances -- is small, while their effect on ride height and hence aerodynamic performance is much larger, to the extent that we believe it could justify the additional weight and design complexity.
"We would therefore question the legality of these systems under Art. 3.15 and its interpretation in [technical directive] TD/002-11, discriminating between whether certain details are 'wholly incidental to the main purpose of the suspension system' or 'have been contrived to directly affect the aerodynamic performance of the car'."
His letter went on to enquire whether two suspension characteristics in particular were considered legal by the FIA:
"1) displacement in a direction opposed to the applied load over some or all of its travel, regardless of the source of the stored energy used to achieve this.
2) a means by which some of the energy recovered from the forces and displacements at the wheel can be stored for release at a later time to extend a spring seat or other parts of the suspension assembly whose movement is not defined by the principally vertical suspension travel of the two wheels."
In a technical directive written in response to Resta's letter, FIA race director Charlie Whiting appeared to confirm that 'trick' suspension systems would not be allowed for the coming season.
The directive said: "In our view any suspension system which was capable of altering the response of a car's suspension system in the way you describe in paragraphs 1) and 2) would be likely to contravene Article 3.15 of the F1 Technical Regulations."
Whiting's directive is not an official rule change but invites other teams to protest the technology to the stewards of any race, who would likely follow the precedent outlined by Whiting. Mercedes and Red Bull will now have to decide whether to continue working on the concepts and hope the stewards rule in their favour or move on to more conservative systems, which are likely being developed in parallel but may also have less of a performance gain.
Testing for the new season begins on February 27 in Barcelona, Spain.