Definition
A section of a crankshaft that is displaced from the main bearing axis, providing the attachment point for a connecting rod. The amount of offset from the crankshaft centerline determines the piston stroke length.
Plain English
The bent, off-center part of a crankshaft where a connecting rod attaches. Because it sits to the side of the shaft's spinning centerline, it pulls the piston up and down as the shaft turns.
Context Anchor
Seen in reciprocating-engine crankshaft descriptions, engine overhaul information, and powerplant maintenance discussions.
Derivation
"Offset" means set away from a central line. "Throw" in mechanical terms refers to the distance a rotating part moves something — here, how far the rod end is thrown out from the crankshaft's centerline. Together: the off-center crank section that throws the rod up and down.
Why Pilots Care
The offset throw determines stroke length, which directly affects engine displacement and power output. Maintenance technicians inspect throws for wear, alignment, and damage because a worn or bent throw can cause severe vibration and engine failure.
Analogy
Think of a bicycle pedal attached away from the center of its axle. Because the pedal is off-center, pushing it makes the axle turn.
Intuition Check
Offset throw does not mean something was thrown out of place by mistake. Here, it means a designed off-center part of the crankshaft that makes piston motion turn into rotation.
Example Sentence 1
The connecting rod bearing rides on the offset throw of the crankshaft, transferring piston force into rotation.
Example Sentence 2
Uneven wear on the offset throw bearings indicated a need for crankshaft inspection during overhaul.