LionsHeart wrote: ↑27 Jan 2026, 08:56
A comprehensive and detailed answer! Thank you. While I generally understand the underlying physics and, to some extent, suspension kinematics, the use of pullrods in Ferrari's in 2012 front suspension has always been somewhat of a mystery to me. Then, in 2013, they switched back to pushrods, but now McLaren has switched to pullrods, and then they switched back to pushrods in 2014. General physics suggests aerodynamic gains? That's what I usually hear from technical experts. If I'm not mistaken, the same thing was said about Red Bull and McLaren in 2022. And now, from Rob Marshall, I learn that pushrod front suspension is dictated by aerodynamics. Let's assume that's true. As someone with a technical background, it's clear to me that some processes, in terms of tire-road interaction and how the chassis affects the tires, must change. In civilian vehicles, everything seems simpler. How much does the presence of a pushrod or pullrods affect the tires longitudinally during braking?
You mentioned dive. But in terms of sensitivity and operating range depending on the wheelbase and chassis width, I'm still pretty clear. Well, it's kind of logical. A short wheelbase gives a go-kart-like agility. In this context, I remember how Mercedes started lengthening the wheelbase every year to slightly extend the underbody, thereby increasing downforce and making the chassis more stable overall.
Overall, I was just trying to understand the critical point of swapping pushrods for pullrods, or vice versa, from a mechanical standpoint, without taking into account aerodynamics, the difficulty of setup for mechanics, and even the center of gravity due to the placement of the mechanisms within the chassis. Is there a direct correlation between how this affects corner entry, corner exit, and braking? Are there any balance changes depending on the pushrod-pusher relationship? About 13-14 years ago, when I first thought about this, I didn't get any definitive answers. It all came down to aerodynamics and how airflow flows through the suspension arms toward the sidepods and floor. From my perspective, I figured if the front suspension had pushrods, then the rear should have pullrods. If the front had pullrods, then the rear should have pushrods. Of course, in my mind, this was justified in the context of balance, not aerodynamics. From an aerodynamic standpoint, I can understand and accept it.
In any case, thank you for your detailed answer. There's something to understand and remember for the future.
Now I have a little time to delve a little deeper into the subject matter. The confusion surrounding Ferrari in 2012/2013 and McLaren illustrates the dilemma perfectly: the aerodynamic advantages are often so great that they force mechanical compromises. But if we completely disregard aerodynamics and the center of gravity (CoG), what remains is a purely mechanical difference in load path efficiency and friction characteristics.
You mentioned braking. Mechanically speaking, a pushrod/pullrod system alone does not necessarily change the geometry of the suspension (the control arm points), but it does change how the vertical load is introduced into the chassis.
Pushrod during braking: Since the rod leads upward to the chassis, it generates a force component during compression (when diving) that tends to push against the upper suspension points.
Pullrod during braking: Here, the force is pulled "downward." The problem with pullrods at the front is often mechanical interference. In order to achieve good geometry for braking (anti-dive), the wishbones must be at certain angles. A pull rod often has to be installed at a very flat angle, which massively increases the internal friction forces in the bearings.
The result for the tire: A pushrod system is usually "stiffer" when it comes to small movements. When braking, this means more direct feedback for the driver. A pullrod system can have higher static friction (stiction) due to the flatter angles, which can make it harder to feel the tire's locking limit. When we talk about the mechanical core, the biggest difference is installation stiffness.
Corner entry: Here you want maximum precision. Since the rockers are located at the top of the chassis in the pushrod, the force path is shorter and the components can be made more solid without disturbing the airflow in the important lower area. This gives the driver a more direct feel for the front axle. When you throw the car into a corner, the pushrod responds more "honestly."
Corner exit (accelerating out): Here, the interaction between the front and rear is crucial. Your theory (push at the front, pull at the rear, or vice versa) is not so far-fetched mechanically! It's all about the pitch platform. When the rear squats during acceleration, the suspension determines how stable the floor plate remains in relation to the asphalt.
Why not always a mixture?
The reason why you often see "front pull/rear push" or vice versa is because of the response rate. A pull rod system at the rear (as was long standard) is great for lowering the dampers, but often has a more progressive spring rate mechanically.
When you combine this with a very linear pushrod front, you get a car that is very sharp when turning in, but "sits" stably when exiting corners. However, as you say, when you look at the mechanical balance, you have to be careful not to introduce too many variables. A car with two different systems is extremely difficult to harmonize in simulation and setup because the friction values and elastokinematics are completely different.
Without aerodynamics, the pushrod would almost always be the mechanically superior choice for the front because it gives the driver more feel through the steering wheel. It is easier to maintain, stiffer, and has less internal friction.
The fact that McLaren and Red Bull used pullrods was actually purely a "sacrifice" to the aerodynamics of the underbody. They accept the mechanical disadvantages (poorer adjustability, higher friction, more complicated load paths) because the gain in clean air to the diffuser and Venturi channels is so enormous that it far outweighs the mechanical losses.
I'm not an aerodynamicist, but to explain it simply and in layman's terms, aerodynamicists – correct me if I'm wrong or if my explanation is inadequate:
Pushrod (front axle): The strut runs from the wheel (bottom) to the chassis (top). It therefore rises towards the center of the vehicle. The air that hits this sloping barrier is deflected along the slope—i.e., upwards and inwards (inwash) towards the top of the chassis and the cockpit.
Pullrod (front axle): The strut runs from the wheel (top) to the chassis (bottom). It slopes down towards the center of the vehicle. The air is directed downwards and outwards (outwash) along this slope towards the tire sidewall and the outer edge of the floor.
In the 2022-2025 era, the Venturi effect was so strong that the underbody literally sucked in air like a vacuum cleaner.
The problem: if the air simply flows straight inwards (inwash), the underbody sucks the turbulent, "dirty" air from the front tires directly into the channels. This would make the ground effect unstable.
The solution: Use pullrod geometry to push the air down and out at the chassis inlet. This "outwash" acts like a protective shield. It pushes the dirty tire air outwards so that the Venturi channels further back can only suck in "clean" air from the front of the vehicle.
But why now pushrod (inwash) for 2026?
The philosophy is changing for 2026 because the cars will be narrower and the "vacuum cleaner effect" of the floor will be massively reduced.
The problem in 2026: Since the cars are narrower, the drag of the tires is the biggest obstacle to top speed (important for overtaking with the new "override" mode).
The solution (pushrod/inwash): The aim is no longer to force the air outwards (which creates drag), but to direct it inwards (inwash) over the chassis. Since the floor will be flatter in 2026, it will no longer be as sensitive to tire turbulence as the deep Venturi tunnels and will work differently. This means you can "afford" to direct more air inwards to make the car more aerodynamically slippery overall, what gives you more performance and - like i said above pushrod is "more honest" and easier to access, so easier to set-up and maintain, so Pushrod gives more advantages this time.
Ferrari's 2012 pullrod solution was actually purely aerodynamic in nature. It was possible to notably raise the lower plane of the monocoque and therefore, influence the aerodynamic flow directed towards the keel, radiator intakes and sidepods. If the FIA hadn't prohibited the passage of air between the upper and lower part of the nose the following seasons, many teams would have followed. But anyway - the high-nose also forced an extreme angle of the pullrods, the dimensions of which were increased. The mechanics and the greater operational difficulty created some problems.
From a structural point of view it imposed greater stress on the upper wishbone and the mounts to the chassis, which had to be reinforced. Also it changed the ratio of the suspension considerably. At equal wheel movement, the rotation of the rocker arm was much reduced compared to that which happens with a pushrod. Flexibility of the elastic elements had to be recalculated, and damper settings, too, to obtain equal ground stiffness.
But I don't think I need to go into any more detail, even though there are a few more interesting things to say about how this suspension worked – ultimately, it was purely aerodynamic, as I hope has become clear. This suspension was retained, even though its advantages disappeared the following year thanks to the FIA, as mentioned above. McLaren's choice the following year, even though the advantage was gone, was simply because they had already developed the suspension and wanted to take advantage of its benefits, and the FIA intervened with its rule change, so they had to live with it and didn't want to/couldn't waste resources on designing a new suspension.
