Tail Swing: Conventional, Reduced and Zero
How tail swing changes where an excavator can work — and when to pay for a reduced- or zero-tail machine versus when conventional is the better value.
Tail swing describes how far the machine's counterweight (the "house" rear) extends past the tracks when the upper structure rotates.
Conventional tail swing
The counterweight overhangs the tracks significantly — often 0.5–1 m on a 20-ton machine. Conventional designs are cheaper, more stable, and lift more for the same weight because the counterweight sits further back. Fine for open sites: mass excavation, rural utilities, pads, pits.
Reduced (tight) tail swing
The counterweight overhang is cut to roughly 15 cm or less past the tracks. Slightly heavier/more expensive for the same dig specs. Examples: Kubota KX080 ("tight tail"), Cat CR models, Komatsu US models, Deere 85G, Volvo ECR series. The right default for road and urban work.
Zero tail swing (ZTS)
The house stays entirely within the track width through a full 360° rotation — nothing to hit behind the machine. Common in minis (Bobcat E-series, Kubota U series, Yanmar ViO, Deere G compacts). Trade-offs: slightly less lift capacity over the side, a more cramped engine compartment (check service access), and more weight for the same dig envelope.
When it matters — translating job language
- "Tight lot", "against a wall/fence", "between houses", "inside a building", "next to live traffic", "working off one lane": specify reduced or zero tail swing.
- "Open field", "new development site", "pit work": conventional is fine and usually the better value — don't pay the zero-tail premium.
- Digging alongside a structure also depends on boom/offset configuration, not just tail swing; minis with swing booms can dig flush against a wall.
General guidance to help you shop — figures are typical ranges, not a valuation. Confirm the specifics of any machine with the seller before you buy.