The 4" x 4" go-kart axle hub is most commonly found on go-karts using 8" wheels. The hub features four lug nuts and are 1-1/16" long. The inner bore is milled for a 1/4" axle key. The most common style for go-karts features a 1" inner (or inboard) shaft diameter with the axle turned down to a 3/4" outer diameter.
Note: Although this 1" step-down to 3/4" axle shaft design is common to many go-kart brands and models, it is incompatible with Yerf-dog 'karts.
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