What sets apart F1 push-rod and pull-rod suspensions?

In Formula 1, teams are split in their adoption of either push-rod or pull-rod suspension configurations. Which teams utilize each type, and what are their respective functions?

Push-rod and pull-rod suspensions are key components in Formula 1 car design, often a focal point of discussion. However, what sets them apart, and why are they significant?

The primary difference between push-rod and pull-rod suspension in Formula 1 lies in their configuration and the direction in which they actuate the suspension components.

In a push-rod suspension setup, the push-rod mechanism is positioned high on the chassis, with a diagonal rod connecting it to a lower point on the wheel assembly. Consequently, when the wheel encounters bumps or curbs, it pushes upward on the torsion spring, causing the push-rod to move upward and toward the chassis.

Conversely, in a pull-rod suspension configuration, the pull-rod mechanism is situated low on the chassis, with a diagonal rod connecting it to a higher point on the wheel assembly. As a result, when the wheel encounters bumps or curbs, it pulls downward on the torsion spring, causing the pull-rod to move upward and away from the chassis.

Both configurations have their own set of advantages and disadvantages, and their selection depends on the specific requirements and preferences of the team. Additionally, the suspension design must align with the aerodynamic concept of the overall car, as it plays a crucial role in directing airflow to various areas of the vehicle, such as the sidepod.

To illustrate, a pull-rod suspension offers improved weight distribution by positioning components closer to the ground, with heavier elements mounted lower on the chassis. This aspect is particularly significant for ground-effect cars, as a lower center of gravity contributes to drag reduction, enhances cornering capabilities, and potentially enhances aerodynamic performance.

Conversely, a push-rod suspension offers practical advantages due to its more favorable local aerodynamic footprint, resulting in cleaner airflow around the suspension components.

Additionally, positioning the suspension parts higher on the chassis facilitates easier maintenance for mechanics. In contrast, a pull-rod layout for the front suspension can create a cramped space, potentially requiring the removal of the floor to access certain parts, thus complicating maintenance procedures.

The push-rod suspension configuration offers improved stability and is also more cost-effective. However, while a push-rod setup may be optimal for one car, it may not be as effective for another, and vice versa for the pull-rod configuration. In some cases, the choice between push-rod and pull-rod suspensions hinges on balancing aerodynamic and performance advantages against cost considerations and practicality, particularly in the context of the ground-effect era.

Furthermore, Formula 1 teams have the option to utilize a combination of both configurations, such as employing a pull-rod setup at the front and a push-rod setup at the rear, or vice versa. This approach allows teams to tailor their suspension setups to specific performance requirements and aerodynamic considerations for different areas of the car.

Which Formula 1 teams employ push-rod or pull-rod suspension configurations in their cars?

For the past two years of ground-effect cars, Red Bull and McLaren have been the sole teams utilizing a pull-rod configuration for their front suspension. However, for the 2024 season, Sauber and Red Bull have emerged as the next teams to adopt a pull-rod setup at the front.

Sauber, in particular, has undergone significant changes following their lower-tier finish in the 2023 constructors’ championship. Meanwhile, Red Bull’s sister team has aligned its development approach more closely with that of the reigning world champions.

Facilitating Sauber’s transition is the presence of technical director James Key, who joined the team from McLaren in September 2023, even though the decision to implement a pull-rod configuration had already been made by then.

He argues that the aerodynamic benefits of a pull-rod configuration outweigh the logistical challenges it poses, emphasizing the importance of managing the turbulent airflow around the car, particularly concerning the front tire wake.

Key predicts that more teams will adopt this approach, as he believes it is the optimal strategy. Red Bull serves as a prime example of the effectiveness of a pull-rod setup, having secured two championships well before the end of the season, including a dominant performance in 2023 with 21 victories out of 22 races. Their suspension system played a crucial role in this success.

The pull-rod suspension contributes to Red Bull’s sharp front end, a preference of their world champion driver Max Verstappen. Its stiffness provides a significant advantage in the ground-effect era, given its low center of gravity.

However, Red Bull opts for a push-rod configuration for its rear suspension, aligning with the majority of the grid. Key notes that the discussion about the rear suspension isn’t as prominent, as a push-rod setup offers mechanical advantages such as allowing for a narrower gearbox and adjustments to the floor shape, ultimately enhancing downforce generation at the rear of the car.

In 2024, the number of teams utilizing a push-rod configuration at the rear has increased to eight, up from five in 2023. This shift occurred as Mercedes and its customer teams, with the exception of Williams, opted to make the transition.

Ferrari, on the other hand, will employ a pull-rod configuration at the rear for the 2024 season. According to technical director Enrico Cardile, this decision stems from the unique characteristics of Ferrari’s rear suspension, which differ from those of its competitors, particularly Red Bull. As a result, the pull-rod structure is deemed more suitable for their setup.

Meanwhile, Williams chose not to follow Mercedes’ lead for various reasons, one of which is the cost-saving advantage associated with sticking to the previous year’s components.

The history of push-rod and pull-rod suspensions in Formula 1 can be traced back to the 1960s and 1970s. The push-rod suspension was first introduced by renowned car designer Colin Chapman, the founder of Lotus. Chapman implemented an inboard suspension setup on the Lotus 21, which achieved a notable second-place finish in the 1961 Formula 1 championship.

Brabham’s Gordon Murray introduced the pull-rod configuration on a BT49 in 1979, marking a revolutionary advancement. This configuration offered greater flexibility compared to the hydro-pneumatic suspension systems of the time, resulting in a lower center of gravity for the car and thus an improvement in performance.

Nelson Piquet’s victory in the 1981 drivers’ championship for Brabham further showcased the effectiveness of the pull-rod suspension. As other teams adopted this innovation, it gained widespread use. However, its popularity declined in the 1990s when a minimum ride height rule was implemented, necessitating a higher center of gravity for the cars.

The pull-rod suspension made a comeback in Formula 1 in 2009 under revised regulations, coinciding with the rearward movement of the diffuser. Adrian Newey, known for his innovative designs, saw an opportunity to optimize the RB5’s aerodynamics by lowering its center of gravity with a pull-rod configuration.

This adjustment proved successful, with Red Bull’s competitive performance demonstrating the effectiveness of the pull-rod suspension in modern F1 cars. Despite utilizing a single diffuser compared to Brawn’s double diffuser,

Red Bull’s strategic use of the pull-rod configuration nearly secured them the championship, highlighting the significant impact of aerodynamic innovations in Formula 1.

In 2010, alongside a double diffuser, Red Bull equipped the RB6 with a pull-rod suspension, initiating a streak of four consecutive double world championships for the team and Sebastian Vettel. This success set a trend within the sport, with 10 out of 12 teams opting for a pull-rod configuration in 2011, followed by Ferrari and Sauber joining the majority in the subsequent year.

Ferrari remained the sole team utilizing a pull-rod suspension for several years, showcasing the configuration on its SF15-T in 2015, before push-rods once again became prevalent across the grid.

However, with the reintroduction of ground-effect cars in 2022, there has been a resurgence of interest in pull-rod suspension systems due to the potential aerodynamic benefits of running closer to the ground.