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Why Formula One Cars Have Huge Grates Hanging Off of Them During Testing

Williams’ Robert Kubica testing in Spain last week.
Williams’ Robert Kubica testing in Spain last week.
Photo: Mark Thompson (Getty Images)

A new Formula One season is a few weeks away, meaning teams are out testing to see if this will be the year anyone can consistently compete with Mercedes. It also means that some cars have enough unfamiliar silver grating hanging off of them to remind to remind a person of their braces days, and for good reason.


“Unfamiliar” is relative, of course, depending on how much attention a person pays to F1 outside of official competition, because slapping these grates on a car for testing is normal. But given all of the photos coming out of winter testing at Circuit de Barcelona-Catalunya in Spain right now, it’s relevant nonetheless.

Those awkward grates hanging off of cars in photos are called “aero rakes,” and F1 teams use them in testing to measure airflow on certain parts of a car. There are huge rakes that sprout from both sides of the car like mechanical wings, like in the photo of Williams driver Robert Kubica’s car above, or teams can strap smaller rakes in any other area where airflow is relevant on the car—the back, the sides, in front of the rear wing, and elsewhere.


F1 has published explainer videos on aero rakes on YouTube for the past couple of years, updating footage and fonts but keeping the same general rundown. The one from 2018 is linked below, and the 2017 video is here. (You’ll have to expand to YouTube to watch both, since F1 doesn’t allow playback here.)

The rakes are made up of things called Kiel probes, as mentioned in the F1 video, which are, as described by Virginia probe manufacturer Aeroprobe, a device used to measure “the total pressure of a flow with high accuracy over a wide range of flow angles.” It’s an adaptation of the Pitot probe that’s also used to measure airflow, via Aeroprobe:

Unlike a Pitot probe, the Kiel probe’s shroud acts to straighten the incoming flow and remove measurement errors associated with varying flow angles. Kiel probes do not require aerodynamic calibration.

The aero rakes and Kiel probes can be used to confirm that cars are performing like they were in virtual simulations, like the video mentioned, and to track the impact of changes to a design, like the often dominant Mercedes team has been doing in Spain. lined out several changes Mercedes made to its aero during testing, including a rerouting of airflow from its front wing, and the team had the aero rakes out on track as well.

Tracking airflow and changes is especially important leading up to this season, since the F1 mandated simplified aero components in an effort to better the racing on track. Team bosses weren’t too happy about the rules last month, but all they can do now is fumble through them until they stumble upon something that works—you know, what most of us do in life.


So, not only do aero rakes look like braces for F1 cars, but they take part in a similar function, too. Teams show up for testing with the changes they’ve made to their vehicles, only to slowly and painfully crank away at small tweaks until everything is smoothed out and in position for the start of the season.

It’s similar, metaphorically, to the slow and painful cranking that occurs in an orthodontist’s chair, as a dental professional whose name you can’t recall stares down at you and somehow enjoys seeing the pain on your face—maybe because you couldn’t remember their name, or maybe because they’re just mean.

Staff writer, Jalopnik

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Rakes like that are good for stopping a RPG-7 from hitting the rear tires. Can’t be to safe