Key terms for understanding vehicles, specs, and maintenance.
- Horsepower — a measure of an engine’s power (rate of doing work).
- Torque — rotational force; what you feel as pulling power off the line.
- RPM — engine revolutions per minute.
- GVWR — Gross Vehicle Weight Rating: max safe loaded weight of a vehicle.
- GCWR — Gross Combined Weight Rating: max for vehicle plus trailer.
- Payload — weight you can add (GVWR minus curb weight).
- Curb weight — the vehicle empty and ready to drive.
- Tongue weight — downward force a trailer puts on the hitch (~10–15% of trailer weight).
- Towing capacity — max trailer weight a vehicle can safely pull.
- CCA — cold-cranking amps; a battery’s cold-start power.
- OBD-II — onboard diagnostics system that stores trouble codes.
- ABS — anti-lock braking system.
- Compression ratio — ratio of cylinder volume at bottom vs top of the stroke.
- Offset (ET) — how far a wheel’s mounting face sits from its centerline.
- Displacement — total volume swept by the engine’s cylinders.
Frequently asked questions
Difference between horsepower and torque? Torque is twisting force; horsepower is the rate of work (torque × RPM).
GVWR vs payload? GVWR is the max loaded weight; payload is what you can add to the empty vehicle.
What is CCA? Cold-cranking amps — a battery’s cold starting power.
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