Nimbus Athletics Portugal: Swim Training Suits Built on Mechanical-Stretch Knit
Nimbus Athletics is a growing Portugal-based activewear label whose swim training suits range now anchors its seasonal offer. When the design team planned a wider range with tighter launch dates, it needed a fabric partner able to guarantee construction consistency, documented performance and shade continuity across every production lot.

Nimbus Athletics: reviewing the fabric swatch set for the swim training suits programme
The challenge
The main risk in the project was fabric going transparent under studio lights. The previous supply chain ran through a trading intermediary, so there was little visibility of the mill, no construction sheet and no test evidence behind the performance claims. Without that documentation the brand could not brief its retail partners with confidence.
The solution
We proposed a dedicated mechanical-stretch knit programme built around a denser double-knit construction with higher GSM. Development started with A4 lab dips and a full construction sheet covering fibre content, GSM, width, stretch and recovery, and colour fastness. Only after the brand approved hand feel and performance targets did the project move to a pre-production lot for fit sampling.

Sample and fit approval for the mechanical-stretch knit construction
Implementation
- Development: lab dips and physical samples in 5 working days.
- Approval: colour, hand feel and stretch signed off in two rounds.
- Bulk: consolidated dye lots to hold shade continuity.
- QC: inline inspection plus final random inspection before packing.
- Testing: ASTM D4966 abrasion resistance on every bulk lot.
Specification delivered
| Parameter | Value |
|---|---|
| Fabric | mechanical-stretch knit |
| Weight | 240 GSM |
| Width | 160–170 cm |
| Stretch | 4-way, recovery above 92% |
| Certification | REACH compliant dyes |
| Colour fastness | Grade 4 or above |
Results
The new mechanical-stretch knit programme helped Nimbus Athletics improved pilling grade from 3 to 4.5. The swim training suits line launched on schedule, and wash durability, opacity and fit consistency all held up through the first retail season. The brand has since extended the programme into additional colours and styles.
“The development process was transparent from the first sample. We finally had the data we needed to brief our retail partners with confidence.” — Nimbus Athletics Product Team

Inline inspection and packing before the swim training suits shipment
Key takeaway
Moving from a trading model to mill-direct development removed the hidden risks in the supply chain. With documented construction, controlled shade management and inline quality control, Nimbus Athletics could concentrate on design and marketing instead of firefighting production issues.