Mercedes and Haas take the lion’s share of the headlines at the United States Grand Prix, with both bringing significant upgrades to Austin. 

The Silver Arrows have brought a new floor to the Circuit of the Americas, a revision that Lewis Hamilton called the last of the team’s “large upgrades” for 2023. 

“It's been a huge amount of work back at the factory and I’m really excited to see how it feels,” the seven-time F1 champion said in Thursday’s Official FIA Press Conference at COTA. “Hopefully this kind of tips the needle a little bit and helps us in the right direction of where we want to pursue next year.”

The floor body of the W14 E now features a raised leading edge that “alters the loading distribution on the outer fence, improving flow quality to the rear of the car and hence rear downforce, while the team has increased “the extent of the high cambered forward section of the floor edge wing” to “increase local load and forward floor load”. 

“I don't know exactly all the different parts of the circuit that I’ll feel it,” added Hamilton. “But hopefully it's a global improvement and hopefully puts us a little bit closer to the guys ahead.”

Haas, meanwhile, have trailered their US Grand Prix update for some time, with driver Kevin Magnussen calling the extensive package an “exciting one, because it’s very different”. 

“It's nice to see the upgrade on the car, finally,” he said, also speaking in Thursday’s Press Conference. “We haven't had many upgrades to the car. It's been a tough year in terms of just finding performance. This upgrade is an exciting one, because it's very different. On paper, it's not actually meant to be more downforce as such, it's a new concept. And it's hopefully the concept that we'll be using for next year's car.”

The update revises many areas of the VF-23, including the floor, sidepods and engine cover. According to the US team “the expansion and contraction of the floor body are now optimised to guarantee less aero sensitivity with car state changes. The new design has also improved the sensitivity in case of strong side wind”. Reshaped floor edges meanwhile “guarantee a more efficient path of the flow driven by the under floor, and increase the aerodynamic efficiency’. 

To work with the new floor design the shape of the sidepod inlet has been changed to “improve the flow around the sidepod, maintaining the same cooling feeding as the previous configuration” and 

“will allow a better interaction of the airflow on the side of the car and in the area between the rear wheels.” To complement that the engine cover has also been changed, with increased cooling exit.  Two new louvre panels and a variety of different blankings have also been created to allow the team to set different cooling levels depending on the circuit and conditions. Additionally, the louvres have “smaller dimensions compared to the previous solution, as the central engine cover cooling exit has been increased”. 

Finally at Haas, the front brake duct inboard exit has been updated with small geometrical changes to improve wake management, with “better flow characteristic coming from the front brake duct inboard exit, gaining aero load with good efficiency”.

Despite the late stage of the campaign, Mercedes and Aston Martin are not the only teams with extensive updates in Austin. 

Aston Martin come to COTA with a suite of changes, including a new diffuser, changed floor edge, and new engine cover and a different beam wing, all aimed at “increasing the loading on the floor by modifying the underside local flow conditions”. 

AlphaTauri also have a new floor this weekend, with changes made to the floor body, fences and the floor edges, again aimed at improving local load. 

According to Faenza squad, “the outermost fence change keeps front-wheel wake losses further away from the forward floor by generating a higher static pressure on their outboard side. The resulting improvement in energy of the flow field to the forward floor gives an increase in local load”.

The floor edges, meanwhile, featured increased camber, with the team saying: “The highly loaded forward part of the floor edge wing has also been extended further rearward compared to the previous geometry. Both of these changes lower static pressure local to that part of the floor edge and helps draw increased mass flow under the forward floor between the fences.”

The Italian team have also brought a new engine cover for improved cooling and revised rear brake ducts to COTA.

Finally, over at Alfa Romeo, the floor again is the focus, with the Hinwil outfit making changes to the rear floor edges of the C43. The alterations have been made to further improve downforce, working with the package of upgrades introduced at the Singapore Grand Prix. 

There are no updates at Red Bull, Ferrari, Alpine, McLaren, or at Williams.