Coil Spring for BMW 3 Series: Cast Iron
This coil spring for the BMW 3 Series is specified around cast iron, which decides how it behaves in service far more than the part name does. We build to a written specification — base material, dimensions, finish and packing — and hold that specification on file so every reorder reproduces the approved piece.
The usual reason a programme changes supplier is not unit price. It is reorders that did not match the approved sample, or inconsistent hardness between lots. Both are specification problems, and both are preventable.
Specification
| Product | Coil Spring |
|---|---|
| Vehicle application | BMW 3 Series |
| Material / finish | Cast Iron |
| Typical use | Rental Fleets |
| MOQ | 3,000 pieces per specification |
| Sampling | 14 working days, 5 days per revision |
| Bulk lead time | 20-40 days after approval |
| Compliance | SAE J431 |
| Packing | 50 pieces per inner box, 500 per carton |
Material options
- EPDM Rubber — preferred when weight matters more than rigidity
- Neoprene — used when the finish has to hold a coating
- Reinforced Nylon — preferred when weight matters more than rigidity
- Zinc Plated Steel — preferred when weight matters more than rigidity
- Titanium Alloy — selected when the part is exposed to weather and road salt
Processes available
- robot welding
- sintering
- heat treatment
- surface grinding
- anodising
- shot blasting
Fitment notes
Confirm the fitment against the VIN or the frame number before ordering; two model years often share a name and not a part.
Where it is used
The specification above is the one most often ordered for rental fleets. Related applications include adventure travel, off-road trails, mountain roads, coastal delivery, urban courier work.
Quality and packing
- In-line inspection with AQL 2.5 sampling on every lot.
- Dimensional report issued against the approved drawing.
- Carton marking and barcode to your specification.
- Golden sample retained at the factory as the reorder reference.
Questions buyers ask
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the SAE J431-compliant build instead of a fresh interpretation.
How long does sampling take?
Samples leave the factory in 14 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.
What is the minimum order quantity?
The standard MOQ is 3000 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
Ask for the current catalogue and the specification sheet for this line.
