Why Are Two Different Yarn Counts Used in French Terry and Fleece Fabric? A Complete Guide to 260 GSM Cotton Fabric

Introduction

In knitted fabric manufacturing, French Terry and fleece fabrics are widely used for sweatshirts, hoodies, tracksuits, and other casual garments. These fabrics are available in different GSM (grams per square metre), constructions, and yarn counts depending on the buyer's requirements.

One common practice in knitting factories is to use two different cotton yarn counts in the same fabric. For example, a 100% cotton fabric with a finished GSM of 260 may use 24/1 Ne yarn for the face and 20/1 Ne yarn for the backing.

But why are two different yarn counts used? What is the difference between face yarn and backing yarn? How do these yarns contribute to fabric weight, thickness, and surface appearance?

This article explains the basic knitting construction, yarn count selection, GSM calculation, and practical considerations for producing 260 GSM French Terry and fleece fabrics.

1. What Is French Terry Fabric?

French Terry is a knitted fabric that generally has a smooth face and looped yarns on the reverse side. The loops provide a distinctive texture and contribute to the fabric's comfort and absorbency.

French Terry is commonly used for:

• Sweatshirts
• Lightweight hoodies
• Joggers and tracksuits
• Casual trousers
• Sportswear and loungewear

Depending on the construction, French Terry can be produced using different yarn counts and knitting arrangements.

2. What Is Fleece Fabric?

Fleece fabric is commonly produced using a knitted construction with a smooth face and a backing yarn system. The reverse side can be brushed or raised to create a soft, fluffy surface.

Fleece fabrics are commonly used for:

• Winter sweatshirts
• Hoodies
• Warm-up suits
• Jackets and casual wear
• Thermal and cold-weather garments

An important difference is that French Terry typically retains its visible reverse-side loops, whereas brushed fleece has a raised, fuzzy surface. However, exact construction depends on the knitting method and finishing process.

3. Understanding Face Yarn and Backing Yarn

In knitted fabrics, different yarn systems can perform different functions.

Face Yarn

Face yarn forms the visible outer surface of the fabric.

Its main functions include:

• Producing a smooth and attractive fabric surface
• Providing the required appearance and texture
• Contributing to fabric strength and dimensional stability
• Influencing the surface coverage and quality of printing

For a 260 GSM cotton fabric, a factory might use 24/1 Ne cotton yarn as the face yarn.

The relatively finer yarn can help create a suitable face appearance, depending on the stitch length, machine gauge, and knitting construction.

Backing Yarn

Backing yarn forms loops or a backing structure on the reverse side of the fabric.

Its main functions include:

• Contributing to fabric weight and thickness
• Providing a looped reverse-side surface
• Supporting the development of a soft, bulky fabric
• Providing fibres for brushing in suitable fleece constructions

A factory might use 20/1 Ne cotton yarn for the backing system.

Since 20/1 Ne yarn is coarser than 24/1 Ne yarn, it contributes more weight per unit length when both yarns have the same actual length.

Important: The exact role of each yarn depends on the machine setup. Some two-yarn constructions use face and backing yarns, while three-thread fleece constructions normally include an additional tie or binding yarn system.

4. Why Are 24/1 and 20/1 Cotton Yarn Counts Used Together?

The combination of 24/1 Ne face yarn and 20/1 Ne backing yarn is one possible yarn arrangement for producing a knitted fabric with a suitable surface and backing structure.

There are several reasons for selecting different yarn counts.

A. To Achieve the Required Fabric Appearance

The face yarn affects the smoothness, surface coverage, and appearance of the fabric. A finer yarn may be suitable when a cleaner and more refined face is required.

B. To Increase Fabric Bulk

The coarser backing yarn can contribute to a fuller and bulkier fabric structure, depending on its loop length and consumption.

C. To Control Fabric Weight

Using different yarn counts provides flexibility in controlling the weight contributed by each yarn system. However, GSM depends on yarn consumption and construction, not simply on the yarn count.

D. To Obtain the Required Hand Feel

The combination of yarn fineness, loop structure, fabric density, and finishing influences the softness, thickness, and overall hand feel.

The final selection should therefore be based on the required GSM, fabric appearance, end use, and production trial results.

5. Difference Between 24/1 Ne and 20/1 Ne Cotton Yarn

In the English cotton count system (Ne), a higher count indicates a finer yarn, while a lower count indicates a coarser yarn.

Parameter	24/1 Ne	20/1 Ne
Yarn count	24	20
Approximate linear density	24.6 tex	29.5 tex
Relative thickness	Finer	Coarser
Weight per 1,000 metres	24.6 g	29.5 g

The approximate conversion from cotton count to tex is:

Tex = 590.5 / Ne

For 24/1 Ne yarn:

Tex = 590.5 / 24 = 24.6 tex

For 20/1 Ne yarn:

Tex = 590.5 / 20 = 29.5 tex

Therefore, 20/1 Ne yarn has approximately 20% more mass per unit length than 24/1 Ne yarn.

This does not mean that a fabric made with 20/1 yarn will automatically have 20% higher GSM. The actual contribution depends on how much yarn is consumed in the fabric.

6. How Is 260 GSM French Terry or Fleece Fabric Achieved?

GSM stands for grams per square metre. It indicates the weight of one square metre of fabric.

For knitted fabrics, GSM is influenced by several factors:

1. Yarn count and linear density
2. Stitch length or loop length
3. Number of yarn systems
4. Knitting machine gauge and diameter
5. Fabric construction and loop geometry
6. Relaxation and dimensional changes
7. Dyeing, washing, brushing, and compacting processes

A fabric cannot be guaranteed to reach 260 GSM simply by selecting 24/1 and 20/1 yarns. The yarn consumption and knitting parameters must also be controlled.

Basic Yarn Consumption Formula

The theoretical contribution of a yarn system to fabric weight can be estimated using:

Yarn weight (g) = Yarn length (m) × Tex / 1,000

If yarn length is known per square metre of fabric, the approximate theoretical GSM contribution is:

GSM contribution = Yarn length (m/m²) × Tex / 1,000

For a fabric with multiple yarn systems:

Total theoretical GSM = Sum of the GSM contributions of all yarn systems

This calculation requires the actual yarn length consumed by each system per square metre of fabric.

Example Calculation

Suppose a hypothetical knitted fabric uses:

• Face yarn: 24/1 Ne, with 4,000 metres consumed per square metre
• Backing yarn: 20/1 Ne, with 6,000 metres consumed per square metre

Face yarn contribution:

4,000 × 24.6 / 1,000 = 98.4 GSM

Backing yarn contribution:

6,000 × 29.5 / 1,000 = 177 GSM

Total theoretical yarn weight:

98.4 + 177 = 275.4 GSM

This is an illustrative calculation, not a production recipe. The assumed yarn lengths are examples only, and actual consumption must be measured or calculated from the real knitting construction.

The example demonstrates why yarn count alone cannot determine the finished GSM.

7. The Effect of Finishing on Fabric GSM

Knitted fabric can change in weight per square metre during wet processing and finishing.

Important processes include:

Relaxation

Relaxation allows the knitted loops to recover from knitting tension. Changes in fabric width and length can affect GSM.

Dyeing and Washing

Wet processing can change the fabric's dimensions and loop structure. Any retained processing materials may also affect measured weight.

Brushing or Raising

Brushing raises fibres from the backing surface to create a soft, fluffy texture. Fibre loss and changes in fabric dimensions can affect the final GSM.

Compacting

Compacting controls dimensional shrinkage and can reduce the fabric's length or width. If the fabric area decreases while its mass remains approximately constant, GSM increases.

For this reason, knitting GSM and finished GSM may be different. Production teams should establish the required target at the correct processing stage.

8. Two-Thread French Terry vs. Three-Thread Fleece

Understanding the knitting construction is essential when selecting yarn counts.

Two-Thread French Terry

A typical two-yarn construction uses a face yarn and a backing yarn. The backing yarn forms loops on the reverse side, which usually remain visible in unbrushed French Terry.

Three-Thread Fleece

A typical three-thread fleece construction uses:

• Face yarn
• Tie or binding yarn
• Backing yarn

The tie yarn helps connect the face and backing structures, while the backing yarn forms loops that can be brushed during finishing.

The exact yarn counts used in each system depend on the required fabric weight, construction, and machine configuration.

Therefore, when a knitting specification mentions 24/1 face yarn and 20/1 backing yarn, the specification should be checked to establish whether an additional tie yarn is present.

9. Practical Checks for Knitting Factories

Before starting bulk production of 260 GSM cotton French Terry or fleece, the knitting and merchandising teams should verify the following:

• Confirm the exact fabric construction.
• Check whether the fabric is two-thread French Terry or three-thread fleece.
• Verify the yarn count and composition for every yarn system.
• Check machine gauge, stitch length, and relevant machine settings.
• Record actual yarn consumption.
• Check grey fabric GSM and width.
• Confirm the required finished GSM after dyeing and finishing.
• Perform a GSM test on the finished fabric.
• Check the face appearance, reverse-side loops, softness, and dimensional stability.
• Approve a trial sample before proceeding with bulk production.

These checks help reduce GSM variation, construction errors, and unnecessary yarn consumption.

Conclusion

Using two different yarn counts in French Terry or fleece fabric is a practical way to balance face appearance, backing structure, fabric bulk, and weight.

For example, 24/1 Ne cotton yarn may be selected for the face, while 20/1 Ne cotton yarn may be used for the backing. The coarser backing yarn contributes more weight per unit length, but the final GSM depends on the actual yarn consumption, loop structure, knitting parameters, and finishing processes.

For a 100% cotton fabric with a target finished weight of 260 GSM, yarn count selection should always be supported by construction verification, consumption calculations, and physical GSM testing.

Understanding the relationship between yarn count, knitting construction, and GSM helps textile engineers, knitting technicians, and garment merchandisers make better production decisions.