I. Travel Mechanism (The most essential difference)

Crawler excavator chassis

• Travel mode: track plates + track rollers + carrier rollers + drive sprockets + idlers

• Power transmission: travel motor + reducer directly driving the tracks

• Structural features: full-track encircling type, large ground contact area

Wheeled excavator chassis

• Travel mode: tires + axles + suspension

• Power transmission: hydraulic motor / gearbox + drive shaft + axles

• Structural features: similar to automobile chassis, equipped with independent suspension or rigid axles

II. Ground contact and stability structure

Crawler excavator

• Track frame + track plates form the undercarriage

• Low ground pressure, no sinking

• Stable enough to operate without outriggers

Wheeled excavator

• Tires + rear axle + front axle

• High ground pressure, easy to sink on soft ground

• Must be equipped with outriggers (H-type, X-type, frog-type) for stable digging

III. Steering structure

Crawler excavator

• Independent drive for left and right tracks

• Capable of pivot steering and center steering

• No steering axle or steering wheel structure

Wheeled excavator

• Front-wheel steering (or 4-wheel steering)

• Equipped with steering gear, steering cylinder, and steering tie rod

• Turns like a car; cannot achieve zero-radius pivot steering