Heavy Vehicle Engineering
Trailer & Heavy Vehicle Engineering
Engineering design for trailers, dollies and truck chassis, backed by hand calculations and FEA and detailed for practical fabrication. Based in Melbourne, working with manufacturers and fabricators across Australia.
What we design
- Trailers, including dangerous goods trailers, flat tops and specialised transport trailers.
- Dollies and converter dollies for heavy-duty and road train combinations.
- Truck chassis and subframes, including tanker and body mounting.
- Components: drawbars, landing legs, container locks, cross members and brackets.
- Fixes for cracking chassis, where fatigue is the real problem.
Built for the road, not just the spreadsheet
A trailer chassis isn't a building beam. Every pothole, hard brake and shifting load sends a shock through the frame, millions of times over its life. Most chassis failures aren't one big overload but fatigue: a small crack at a weld, a hole or a sharp change in section that grows until the rail lets go.
That's why we check more than static strength. We design to the factors of safety in VSB 6, look closely at fatigue-sensitive details, and use FEA to see where the stress actually concentrates, then put the strength there. The result is a chassis that's strong where it needs to be, without carrying extra weight everywhere else.
What you get
- Hand calculations for the critical load cases: static, braking, cornering and dynamic loads.
- Finite element analysis of the chassis and critical components, including fatigue-prone details.
- 3D models and fabrication drawings with weld details your workshop can build from.
- An engineering report to support compliance with the ADRs, NHVR requirements and VSB 6, ready for review by your AVE where one is needed.
Related projects and reading
Heavy-Duty Tri-Axle Dolly
Design, modelling and hand calculations for a heavy-duty tri-axle dolly.
View projectDangerous Goods Trailer
A tri-axle DG trailer engineered to the ADRs and NHVR requirements.
View projectTanker Truck Chassis
A chassis designed to carry a tanker and the shifting loads of liquid cargo.
View projectWhat factor of safety for a trailer chassis?
What VSB 6 requires, and why fatigue drives it.
Read the answerFrequently asked questions
What factor of safety should a trailer chassis be designed to?
VSB 6 requires a design factor of safety of 3 for body mounting components and a minimum of 5 for tippers and off-highway vehicles, measured against the material's yield strength. Fatigue is the main reason the factors are that high. We've written a full answer in our Insights section.
Can you certify my trailer or modification?
We provide the engineering design and calculations. The compliance pathway depends on whether it's a new build or a modification: new vehicles must meet the Australian Design Rules, and many modifications need sign-off by an Approved Vehicle Examiner (AVE), who will review the engineering. We'll tell you up front what your job needs.
Do you work with manufacturers outside Victoria?
Yes. Trailer and chassis design work is done from drawings, models and calculations, so we work with manufacturers and fabricators across Australia.
Can you check an existing design that's cracking?
Yes. Cracking in a chassis is usually a fatigue problem at a weld, a hole or a sudden change in section. We look at where the cracks are, work out why the stress is concentrating there, and design a fix rather than just adding more steel.