Technical Draft: The curious case of Ricciardo’s brakes

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Daniel Ricciardo is being left in the dust by his ten-year younger McLaren teammate Lando Norris, the highly-rated Australian’s struggles are well a big talking point as he is finding the sweetspot with the MCL35M elusive; could his problem be brakes-related?

The admirable performance development curve of McLaren has continued in 2021 on the positive slope it has been following since the rock bottom of days that ended in 2018 with the termination of their less than fruitful partnership with its then power unit partner Honda.

A combination of innovative and effective engineering, their new power unit partnership with Mercedes and the stand out performances of Lando Norris has resulted in the Surrey team sitting third in the Formula 1 Constructors’ Championship with a 19 point lead over Ferrari in fourth and an obvious performance superiority over the Scuderia.

Curiously though, with a current WCC tally of 141 points, and Norris having scored over 70 percent of them, there appears to be a significant performance difference between Norris and his teammate Daniel Ricciardo.

Driving for three teams over the last four years, Ricciardo has struggled to adapt to the characteristics the MCL35M and match the performance levels that his teammate has been capable of, and much of this has been attributed to braking.

The advent of the modern turbo-hybrid era of Formula One in 2014 and the associated changes in the energy recovery systems (ERS) have necessitated fundamental change in the design of an F1 braking system, the primary change being the integration of a brake-by-wire (BBW) system on the rear which has resulted in much smaller rotors and callipers needing to be used.

As the kinetic ERS sub-system (ERS-K) recovers energy under braking, the drag of the electric motor (MGU-K) also provides retardation which contributes to slowing the car. Nevertheless, as the MGU-K retardation is not constant due to variance because of the battery charge state and associated instantaneous regenerative settings, so too will the retardation the system provides vary.

A present-day F1 braking system is comprised of two hydraulic loops with front and rear master cylinders mounted at the brake pedal in the cockpit, but the rear system will rather terminate at the BBW unit mounted inside the gearbox housing than at the calliper.

In effect, the BBW system will sense the braking demand by the driver using very sophisticated software, and provide the driver with a consistent braking event, taking into account the inconsistencies of ERS interruption.

Importantly, the rear BBW system does not replicate in full the conventional pedal feel, which drivers generally sense instinctively.

In the days before ERS regen and rear BBW, F1 braking system events were essentially binary in that a driver applied brake pressure as late as they would dare as hard as they could and releasing the pedal at the end of the braking event, modulating that pressure to avoid wheel lock only if necessary.

However, due to rear BBW, significantly heavier cars and a different pedal feel, braking events are no longer binary and other braking techniques such as trail and cadence braking have become necessary in the pursuance of lap time, and drivers have needed to reprogram instinctive braking intuition to accommodate.

Rear BBW system solutions in F1 are not generic; they are bespoke and nuanced with differing characteristics which can complicate a the transition of a driver when changing teams.

It is widely acknowledged that in 2014 with the introduction of the new regulation regime that F1 is currently framed that Ricciardo adjusted more effectively and performed better than his then teammate Sebastian Vettel, and the regen/BBW behavioural characteristics were an important aspect he adapted to better.

In 2019 Ricciardo suffered from similar difficulties at Renault to what he is experiencing in 2021, and the R.S.19 was a design with which he had no initial fundamental design input into.

Conversely, in 2020 Ricciardo’s performance improved notably as the R.S.20 was designed with the inclusion of his input and feedback, and the resultant improvement in braking characteristics were noted on several occasions.

Recently, McLaren Technical Director James Key remarked on Ricciardo’s 2021 struggle, “Where differences come in are things like engine braking and how that works, how to tune it accordingly, how the chassis works, how the aerodynamics works and supports the car in certain conditions.

“Is it strong in a straight line, which is what we’ve always been, or a little bit weaker if you’re trying to carry the brakes into a corner, or [in] certain types of corner where you have different kind of braking conditions?”

This year Daniel has said: “I’m trying to programme myself to basically learn how to drive it faster. So I’m back at school.”

The following F1 Insights AWS data graphic from last weekends Austrian Grand Prix is a typical example that tells same story.

The graphic demonstrates that Ricciardo’s initial brake application was harder than Norris’s, but he was releasing the pedal sooner and for a longer amount of time. Norris was trail braking less, generating more braking power and braking for a shorter period of time.

Norris was washing off more speed than Ricciardo in less distance whilst generating more braking power but exerting less g-force.

Braking behaviour can be modified by changing a combination of rotor and pad material type, rotor thickness, master cylinder sizing, brake ducting type and sizing, pedal leverage length and even tyre compound and pressure, but in the age of regen/BBW rear braking, fundamental braking characteristics are a result of BBW system software and valving.

Unfortunately, for the remainder of 2021, any braking system improvements for Ricciardo may well only be minor or short term fixes as he was for the opportunity for his input and requirements to be more broadly implemented into the 2022 McLaren design.

It might be a long and painful wait, but I expect that 2022 will be a much better season for Daniel Ricciardo.