Tandem Trailer Axles Specification Example for Trailer Axles: Sealed Unit
Tandem Trailer Axles Specification Example for Trailer Axles: Sealed Unit
This is a worked specification for tandem trailer axles in a sealed unit programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The sealed unit version exists because the duty cycle on trailer axles is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually packing that arrived crushed at the port.

Example specification
| Item | Tandem Trailer Axles |
|---|---|
| Application | Trailer Axles |
| Version | Sealed Unit |
| Base material | Sintered Metal |
| Controlled dimensions | 5 key dimensions, recorded per lot |
| Tolerance band | ±0.05 mm |
| Finish | as machined |
| MOQ | 200 pieces per specification |
| Sampling | 7 working days, 3 days per revision |
| Compliance | ECE R90 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Sintered Metal, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- heat treatment
- shot blasting
- gravity casting
- powder coating
- die casting
- laser cutting
Where this example applies
Programmes that run sealed unit most often specify this build for trailer axles. Related applications include workshop replacements, utility trailers, boat trailers, delivery vans, emergency vehicles.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 2.5 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
How long does sampling take?
Samples leave the factory in 7 working days, and each revision round adds about 3 days once you have seen the first piece.
What testing is included?
Standard lots ship with dimensional and hardness reports. ECE R90 documentation is issued with the shipment when your market requires it.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 200 pieces per line.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.



