Underbody Tray

Lore & Background

In the tuning garages of the Forza world, the Underbody Tray occupies a humble but essential place. Where a rear wing is the flashy, visible statement of a car's aero intent, the tray is the quiet workhorse hidden from view. Mechanics and players alike treat it as the first aero part they reach for when a car feels floaty at the top of a long straight, because the effect is immediate and the cost in drag is modest compared to slapping on a giant rear wing.

The part's design philosophy is straightforward: a flat, slightly contoured panel that closes the gap between the road and the car's underbody. In the Forza tuning system, upgrading through the grades of tray progressively increases the downforce contribution while keeping the drag penalty manageable. It is not a part that transforms a car's character, but rather one that refines and stabilises it, making the difference between a confident, planted feel and a nervous, wandering one at the upper end of the speed range.

Fans of the series often pair the Underbody Tray with a rear diffuser and a moderate rear wing to build a balanced aero package that works across a variety of track types, from the open highways of Forza Horizon's open-world maps to the tight corners of circuit racing in Forza Motorsport. It is the part that reminds players that aerodynamics is not just about what you can see.

In Their Own Story

The garage lights hummed their low fluorescent buzz as Mara wiped the last of the grease from her hands and stared at the car jacked up on the two-post lift. The rear wing was on, the front splitter was fitted, but something still felt wrong on the long back straight at the coastal circuit. She pulled the Underbody Tray from its crate—Gold grade, the one she'd saved up for—and slid it into place beneath the chassis, tapping it flush with the cross-members. She dropped the car, fired the engine, and felt that subtle, reassuring press against the tarmac as the speed climbed past 180. The car stopped wandering. The car stopped breathing. It just held, steady and sure, like it had always been meant to go that fast.

Reader's Guide

The Underbody Tray is a performance part, not a vehicle, so it carries no standalone power figure, curb weight, or handling score. Instead, it modifies the car it is fitted to. In practical terms, installing a tray adds a measurable chunk of downforce with a small drag penalty, making the car feel more planted at high speed while shaving a tiny amount off theoretical top speed. It is available in several grades; higher grades deliver more downforce for a slightly larger drag cost.

In the tuning menu, the tray occupies the underbody/aero slot. You can swap it in or out freely, and its effect stacks with other aero parts—front splitter, rear diffuser, rear wing—so a full aero kit multiplies the total downforce. The trade-off is always drag: more downforce means the car is harder to push to its ultimate top speed, so on very long, flat straights you may want a lighter aero setup, while on tracks with fast corners and elevation changes the extra grip is worth the drag.

Because the tray is a flat, simple panel, it is one of the least likely parts to cause fitment conflicts, and it is available for a very wide range of car classes, from compact hatchbacks to large GT tourers. It does not change the car's class, engine, or transmission.

Build philosophy: treat the Underbody Tray as the foundation of your aero package—fit it first, then layer the rest of the kit around the stability it gives you.

Did You Know?

• The Underbody Tray is one of the most universally applicable performance parts in the Forza tuning system, available for a very wide range of car classes and body styles.
• Because it generates downforce without the large drag penalty of a full rear wing, it is often the preferred first aero part for players who want stability without sacrificing much top speed.
• In the Forza tuning menu, the tray sits in a dedicated underbody slot, meaning it does not conflict with front splitter, rear diffuser, or rear wing parts and can be combined with all of them.
• The part is visually hidden beneath the car in normal driving; its effect is felt in the car's behaviour rather than seen, making it one of the most 'invisible' upgrades in the game.