Aluminum Alloy Wheel Hub Specification Example for Emergency Vehicles: Sealed Unit
Aluminum Alloy Wheel Hub Specification Example for Emergency Vehicles: Sealed Unit
This is a worked specification for aluminum alloy wheel hub 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 emergency vehicles is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a specification nobody had written down.

Example specification
| Item | Aluminum Alloy Wheel Hub |
|---|---|
| Application | Emergency Vehicles |
| Version | Sealed Unit |
| Base material | Forged Aluminium |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | zinc plated |
| MOQ | 500 pieces per specification |
| Sampling | 7 working days, 5 days per revision |
| Compliance | RoHS |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Forged Aluminium, 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
- electroplating
- laser cutting
- cold forging
- ultrasonic cleaning
- robot welding
- anodising
Where this example applies
Programmes that run sealed unit most often specify this build for emergency vehicles. Related applications include emergency vehicles, aftermarket retail, long-haul trucks, municipal fleets, trailer axles.
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
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
How long does sampling take?
Samples leave the factory in 7 working days, and each revision round adds about 5 days once you have seen the first piece.
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.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 500 pieces per line.
Ask for the current catalogue and the specification sheet for this line.



