Container Chassis Sizes: 20ft, 40ft and 45ft Compared

Container chassis sizes come down to two decisions: which box lengths you need to run, and whether a fixed-length frame or an extendable frame fits your mix of container sizes better. Get both right and the rest — axle count, gooseneck versus flat frame, twist-lock layout — follows from there.

Note this is a different question from used-versus-new. We only build new chassis; see the note on total cost below if you're weighing a used unit.

20ft, 40ft and 45ft: Fixed vs Extendable Frame

A fixed 40ft container chassis (12,192mm) is the lighter, lower-cost build for fleets that move one box size consistently. An extendable frame slides between 6,058mm and 12,192mm, covering 20ft and 40ft boxes on the same chassis — useful for fleets with a mixed container mix, at the cost of roughly 400-600kg more tare weight than a fixed-length unit. We don't build a dedicated 45ft chassis; extendable frames and 40ft fixed units with adjusted rear bolsters cover most 45ft container work.

Gooseneck vs Flat Frame

Our skeletal trailer platform runs a flat frame with a low deck height of 1,500mm, which keeps overall vehicle height within road limits for standard port and depot cycling. A gooseneck-style chassis drops the front section lower still, which matters more for oversize or high-cube container work than for standard ISO boxes — most port drayage and intermodal fleets run the flat frame version since it's lighter and cycles faster.

Twist-Lock Layout and Axle Count

Twist-lock housings are set to ISO 1161 corner-casting spacing — 4 sets for a 20ft box, 8 sets for a 40ft box — so standard, high-cube and reefer containers load without adaptor plates. Axle count runs 2 or 3 axles at 13 tons each; 2-axle chassis suit lighter depot and yard cycling, while 3-axle builds carry the full 34,000kg payload rating for cross-border and highway haulage.

New vs Used Container Chassis

We build new chassis only. A used 20ft or 40ft container chassis at a lower asking price is common in the secondhand market, but twist-lock housings and locking pins are the components that wear first under daily terminal cycling — exactly the parts that are hardest to inspect from overseas before purchase. Between forged-steel locking pins on a new chassis and stamped brackets on a used one after years of cycling wear, the total cost of importing a new chassis often comes out lower than it looks on paper once repair and downtime on a used unit are factored in.

Where to Go From Here

For the full spec sheet on our standard 40ft fixed chassis, see the 40ft container chassis page. For the complete range including the extendable frame option, see our container chassis trailer page.