Ripstop Fabric Strength: Why Higher GSM Isn’t Always Stronger

These are three real production cases we discuss with workwear brands, garment manufacturers, and sourcing teams who ask us to explain a ripstop specification sheet rather than just quote a GSM number.

Three T/C 65/35 Ripstop Fabrics: Actual Test Results

All three fabrics share the same T/C 65/35 composition and ripstop construction. Their yarn counts, densities, and lab results differ.

Specification / Test Result	Fabric 1	Fabric 2	Fabric 3
Fabric weight	220gsm	260gsm	280gsm
Composition	T/C 65/35	T/C 65/35	T/C 65/35
Yarn count spec*	20 × 16	16 × 16	16 × 12
Density spec*	108 × 56	108 × 52	104 × 50
Tensile force — warp	1,690 N	1,819 N	1,718 N
Tensile force — weft	1,028 N	716 N	1,055 N
Tear force — warp	85 N	88 N	98 N
Tear force — weft	77 N	44 N	116 N

*Construction figures reproduced as recorded in production specs; count system and density units not specified. Tensile: ISO 13934-1 (strip method). Tear: ISO 13937-1 (pendulum/Elmendorf method).

Tensile test (ISO 13934-1) Measures maximum force during a strip tensile test. Buyers often call this “tensile strength,” but the reported figure is a force value, in newtons.

Tear test (ISO 13937-1) Measures the force needed to propagate a tear from an existing cut, using the ballistic pendulum (Elmendorf) method — a different mechanical response from tensile testing.

A fabric can lead one measurement without leading another — as these results show.

Why Did the 260gsm Fabric Have Lower Weft Strength?

Fabric 2 was 18.2% heavier than Fabric 1, but its weft results were substantially lower:

GSM alone would not reveal this. But calling the 260gsm fabric simply “weaker” misses part of the picture too:

The Weft Yarn Was an Intentional Cost Decision

Fabric 1 used ring-spun yarn throughout. For Fabric 2, we selected open-end spun yarn in the weft — a deliberate choice. The customer had a strict cost target and no particularly demanding weft-strength requirement, so the yarn combination balanced those two priorities.

Fabric development is not always an exercise in maximizing every test result. A buyer needs a construction suited to the garment’s requirements and target price. For a project with a demanding weft-strength requirement, the same selection could be the wrong call — which is why the performance brief has to come before the yarn decision, not after it.

In this case, the weft yarn was one contributing factor in the lower weft results. It should not be read as a general claim that open-end yarn always produces weaker fabric.

Spinning Method Was Not the Only Variable

The two fabrics also carried different construction specifications:

	Yarn count	Density
Fabric 1	20 × 16	108 × 56
Fabric 2	16 × 16	108 × 52

These were different production fabrics, not a controlled trial isolating spinning method as the only variable. Research comparing open-end and ring-spun woven fabrics shows yarn structure can influence behavior such as crimp and tearing performance, but it does not tell us how much of the difference in our samples came from that factor alone (Mohamed and Lord, Comparison of Physical Properties of Fabrics Woven from Open-End and Ring Spun Yarns).

Our practical conclusion is narrower: buyers should understand the yarn specification behind a quoted GSM, especially when comparing fabrics built for different cost targets.

The 280gsm Fabric Changes the Ranking Again

Fabric 3 recorded the highest tear force in both directions — 98 N warp, 116 N weft — roughly 2.64× the 260gsm fabric’s weft tear result. It also led weft tensile force at 1,055 N. But it did not lead every measurement: its warp tensile force, 1,718 N, was 5.6% below Fabric 2’s 1,819 N.

Measurement	Highest result among these samples
Warp tensile force	260gsm — 1,819 N
Weft tensile force	280gsm — 1,055 N
Warp tear force	280gsm — 98 N
Weft tear force	280gsm — 116 N

The heaviest sample won three of four measurements — but weight alone didn’t predict all four, and a numerical gap shouldn’t be treated as statistically significant without variability data.

What Matters Besides GSM?

GSM tells a buyer how much a square metre of fabric weighs. To understand strength, we need to examine how that fabric was built.

Yarn count and actual yarn properties. A construction spec lists yarn counts, but counts alone don’t describe yarn quality. Spinning method matters too — as the 260gsm case shows.

Warp and weft density. The three fabrics used different density specs. Effects can’t be reduced to “more threads always means greater strength” — under tearing, yarn movement and grouping affect how load is shared.

Base weave and ripstop arrangement. “Ripstop” doesn’t describe every structural detail. Understanding the reinforcement layout and yarn interaction explains why fabrics with the same construction label can behave differently. Research on woven-fabric tearing treats yarn linear density, thread density, and weave as interacting variables — not a formula for predicting these three test results (Tear Resistance of Woven Textiles — Criterion and Mechanisms).

Processing and test conditions. Finishing and laundering history should be established for any tested sample. Those details aren’t supplied in this comparison, so we don’t assign the observed differences to a particular finish.

The point is to connect the test result to an identifiable fabric specification — not to a weight number on its own.

What Buyers Should Ask a Supplier Besides GSM

A useful sourcing brief starts with the garment and its likely demands — work trousers exposed to snags, repeated kneeling, or stress around pockets may need different evaluations. When comparing ripstop quotations, ask:

1	What are the tensile and tear results in both directions? Request the figures separately rather than accepting a general “high-strength” description.
2	Which methods and test conditions were used? Check the standard, units, sample condition, and report reference — results from different tear methods aren’t directly interchangeable.
3	What yarn and construction specifications support those results? Confirm counts and units, warp/weft density, spinning method, and ripstop arrangement.
4	What performance requirement is driving the selection? Agree the required results and target cost — Fabric 2 shows how much that discussion can affect yarn choice.
5	What else needs validation before bulk approval? Tensile and tear figures don’t establish abrasion resistance, seam performance, comfort, or post-laundering durability — include the evaluations relevant to the finished garment.

FAQ

Learn more on our Ripstop Fabric pillar page.