What is another word for the subframe on a car?

There isn't a single perfect synonym for "subframe" as it's a fairly specific term in automotive engineering. However, depending on the context, you could use some of these alternatives:

General terms:

* Chassis: This refers to the entire supporting structure of the vehicle, which includes the subframe.

* Frame: This is a broader term that encompasses both the main frame and subframes.

* Undercarriage: This refers to the underside of the car, which includes the subframe.

More specific terms:

* Auxiliary frame: This emphasizes that the subframe is a separate part of the chassis, rather than the main frame.

* Support structure: This emphasizes the function of the subframe, which is to support various components.

* Crossmember: If you're talking about a specific part of the subframe, you could use this term.

Ultimately, the best word to use depends on the specific context and what you're trying to communicate.