Answer: axletree

AnswerCrossword Clue
AXLETREEGo-cart support
AXLETREECart's wheel attachment
AXLETREECarriage underpinning.
AXLETREEWheel's attachment on a horse-drawn cart
axletreebar, fixed crosswise under an animal-drawn vehicle, with a rounded spindle at each end upon which a wheel rotates
axletreea type of axle (a shaft upon which a wheel revolves)