The two C-shaped longitudinal components of a truck frame are called the

• A. Side rails
• B. Frame rails
• C. Crossmembers
• D. Stringers

Answer: (C)

The main idea here is recognizing frame terminology by orientation. The two long, channel-shaped pieces that run the length of the truck frame are the frame rails (often called side rails). They form the backbone of the chassis and carry the vehicle’s bending and torsional loads along the length.

Crossmembers are the pieces that connect the rails across the width of the frame, providing transverse stiffness and giving mounting points for the body, engine, and drivetrain. Stringers are additional longitudinal members that can stiffen the structure between major rails, but they aren’t the primary long rails themselves.

So, the two long longitudinal members are frame rails. Crossmembers are the transverse connectors between them.