Have you ever noticed a T-shirt that looks perfectly straight when purchased but develops twisted side seams after a few washes?
The side seam gradually moves towards the front or back of the garment. The bottom hem may also appear uneven, making the T-shirt look poorly stitched.
This problem is commonly associated with fabric spirality, also known as skewness or torque-related distortion in knitted fabrics.
Although polyester is generally known for its dimensional stability, certain polyester knitted fabrics can still experience spirality because of yarn characteristics, knitting construction, fabric finishing and residual tensions.
For garment manufacturers, clothing brands and bulk fabric buyers, understanding spirality is important because the defect can affect garment appearance, fit, production quality and customer satisfaction.
In this guide, we explain what spirality is, why it develops, how it is measured and what manufacturers can do to reduce it.
1. What Is Spirality in Knitted Fabric?
Spirality is a fabric distortion in which the knitted wales and courses do not maintain their intended alignment.
In circular-knitted fabrics, the loops may develop a slight inclination because of yarn torque, machine construction or processing conditions.
When the fabric relaxes during washing, this distortion can become more noticeable.
In a finished T-shirt, spirality may appear as:
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Side seams shifting towards the front or back.
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A twisted garment body.
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Uneven alignment between the front and back panels.
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A bottom hem that no longer sits straight.
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Distortion of printed graphics or garment panels.
Spirality is particularly associated with single jersey knitted fabrics, although other knitted constructions can also exhibit distortion.
Important: Not every twisted T-shirt is caused by fabric spirality. Incorrect cutting, sewing tension, fabric grain misalignment and finishing problems can produce similar symptoms.
2. Why Does Spirality Become Visible After Washing?
During knitting, dyeing, finishing and garment manufacturing, fabric can retain mechanical stresses.
These stresses may temporarily remain within the material.
When a garment is washed, the fabric is exposed to water, mechanical movement, temperature changes and subsequent drying.
These conditions allow some residual stresses to relax.
As the knitted structure moves towards a more relaxed configuration, the fabric may change shape.
If the original fabric contains significant loop distortion or yarn torque, the garment can develop visible twisting.
For example, a T-shirt may initially have perfectly aligned side seams.
After several washing cycles, one side seam may shift towards the front while the opposite seam shifts towards the back.
The garment may still retain approximately the same overall size, but its shape has changed.
This is why dimensional stability should not be evaluated through shrinkage measurements alone.
3. The Science Behind Spirality in Circular Knitting
To understand spirality, it helps to understand how knitted fabric is constructed.
Unlike woven fabrics, which are formed by interlacing warp and weft yarns, knitted fabrics are created through interconnected loops.
Two important structural directions are:
Wales: Vertical columns of knitted loops.
Courses: Horizontal rows of knitted loops.
In an ideal reference structure, these directions maintain the intended alignment.
However, actual knitted fabrics may contain inclined loops because of yarn torque and the geometry of circular knitting.
When the fabric relaxes, the inclination may become more pronounced.
This creates the characteristic twisting associated with spirality.
The degree of spirality depends on several interacting factors rather than a single property.
4. Major Causes of Spirality in Polyester Knitted Fabric
4.1 Residual Yarn Torque
Yarn torque is one of the important factors influencing spirality.
During yarn manufacturing, twisting or texturing can introduce internal stresses.
When the yarn is knitted into fabric, these stresses can influence the orientation of the knitted loops.
If the yarn attempts to rotate or untwist during relaxation, the fabric structure may become distorted.
Yarn torque is especially significant in certain spun-yarn single jersey constructions.
In filament polyester fabrics, the effect depends on yarn type, texturing, twist and processing history.
4.2 Circular Knitting Machine Construction
Circular knitting machines produce fabric continuously around a cylindrical needle arrangement.
The knitting process can create a helical course path.
The relationship between machine rotation, yarn feeding, take-down tension and fabric construction can influence the alignment of the knitted structure.
This does not mean every circular-knitted fabric will develop unacceptable spirality.
However, the machine configuration and production settings can affect the final result.
4.3 Stitch Length Variation
Stitch length refers to the amount of yarn used to form a knitted loop.
It influences fabric density, flexibility and dimensional behaviour.
Longer or shorter stitch lengths can change how the fabric responds during relaxation.
Inconsistent stitch length may also produce uneven fabric behaviour.
Maintaining appropriate stitch length is therefore important for dimensional stability.
4.4 Yarn Type and Texturing
Polyester knitted fabrics can be manufactured using different yarn types.
Examples include:
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Draw Textured Yarn (DTY).
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Fully Drawn Yarn (FDY).
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Spun polyester yarn.
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Polyester blended yarns.
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Twisted polyester filament yarn.
Each yarn type has different structural and mechanical characteristics.
For example, DTY contains crimp introduced through texturing, while FDY generally has a smoother filament structure.
However, DTY does not automatically produce more spirality than FDY.
The actual result depends on yarn torque, twist, construction, processing conditions and finishing.
4.5 Uneven Fabric Tension During Production
Fabric tension can influence how knitted loops are arranged.
Excessive or uneven tension during knitting, dyeing or finishing may temporarily distort the structure.
When the fabric later relaxes, this distortion may change.
Poor tension control can therefore contribute to dimensional instability.
4.6 Improper Fabric Relaxation
Knitted fabrics often require controlled relaxation before cutting.
If fabric is cut while significant residual tension remains, the garment panels may change dimensions or alignment later.
This can contribute to twisting, seam displacement or uneven garment shape.
The required relaxation procedure depends on the fabric construction and processing history.
4.7 Heat-Setting Conditions
Polyester is a thermoplastic fibre, meaning its structure responds to heat.
Heat setting can help stabilize polyester fabric dimensions and reduce certain residual stresses.
However, the effectiveness of heat setting depends on:
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Processing temperature.
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Exposure time.
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Fabric tension.
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Overfeed.
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Width setting.
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Yarn composition.
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Presence of elastane.
Incorrect heat-setting conditions may leave the fabric insufficiently stabilized or introduce additional dimensional problems.
5. Why Is Spirality Commonly Associated With Single Jersey Fabric?
Single jersey is one of the most widely used knitted constructions for T-shirts.
It is lightweight, flexible, economical and suitable for numerous garment applications.
However, its loop structure is relatively unbalanced compared with some double-knit constructions.
This makes certain single jersey fabrics more susceptible to torque-related distortion.
In contrast, constructions such as interlock can provide greater structural balance.
That does not mean interlock is completely immune to distortion.
The yarn, machine settings and finishing process still matter.
For manufacturers producing large quantities of T-shirts, the choice of fabric construction can significantly influence garment stability.
6. Does 100% Polyester Fabric Experience Spirality?
Yes.
Although polyester generally has good dimensional stability, a 100% polyester knitted fabric can still develop spirality.
The reason is that fibre dimensional stability and fabric structural stability are different properties.
Polyester fibres may resist conventional washing shrinkage while the knitted loop structure still undergoes distortion.
A fabric can therefore show limited shrinkage but noticeable seam twisting.
This distinction is important when evaluating polyester fabrics for bulk garment production.
7. Can Polyester-Lycra Fabric Develop Spirality?
Yes, although its behaviour may differ from that of 100% polyester fabric.
Polyester-Lycra fabrics contain elastane, which contributes stretch and recovery.
The additional elastic component can influence how the knitted structure responds to tension and relaxation.
Depending on the construction, the fabric may experience:
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Uneven relaxation.
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Dimensional changes.
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Torque-related distortion.
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Differential tension effects.
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Garment-panel deformation.
However, elastane content alone does not determine spirality.
Fabric construction and processing conditions remain critical.
8. Spirality vs Shrinkage: What Is the Difference?
Spirality and shrinkage are two different forms of dimensional change.
| Property | Spirality | Shrinkage |
|---|---|---|
| Main effect | Twisting or angular distortion | Reduction in length or width |
| Typical symptom | Side seams rotate | Garment becomes smaller |
| Main concern | Shape and alignment | Garment measurements |
| Common contributing factors | Yarn torque, loop geometry, processing stresses | Fabric relaxation, thermal history, finishing |
| Testing focus | Angular distortion or seam displacement | Percentage dimensional change |
A T-shirt may experience both spirality and shrinkage after washing.
For this reason, fabric testing should evaluate more than just GSM and shrinkage percentage.
9. How Is Fabric Spirality Measured?
Spirality can be evaluated through standardized textile-testing procedures.
Depending on the selected method, laboratories may measure the angular displacement of the knitted structure or the movement of garment seams after laundering.
One relevant test method is AATCC TM179 – Skew Change in Fabric and Garment Twist Resulting from Automatic Home Laundering.
A simplified garment evaluation involves the following steps:
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Select a representative garment sample.
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Record its original seam alignment and dimensions.
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Wash and dry it under defined test conditions.
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Allow the garment to condition as required.
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Measure the resulting seam displacement.
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Compare the result against the agreed acceptance criteria.
For a simplified illustration, if the lateral seam displacement is 2 cm over a 60 cm reference length:
Spirality percentage = (2 ÷ 60) × 100 = 3.33%
This is only an illustrative displacement ratio. Official laboratory results must follow the calculation and specimen preparation specified by the chosen test method.
There is no single universal spirality acceptance limit suitable for every fabric or garment.
Acceptable performance should be agreed upon according to the buyer's specifications, intended application and relevant testing standard.
10. How Spirality Affects Garment Manufacturing
Garment Appearance
Twisted seams can make a garment appear defective even when its colour, stitching and fabric quality are otherwise acceptable.
Printing Alignment
Screen-printed or heat-transferred graphics may appear misaligned when the garment body twists.
Pattern Matching
Stripes, engineered prints and panel designs become difficult to align when the fabric structure is distorted.
Production Rejection
Garments that fail buyer specifications may require rework, replacement or rejection.
Customer Complaints
Consumers may notice twisting only after washing the garment at home.
This can affect customer satisfaction and brand reputation.
For large-volume garment manufacturers, spirality can therefore create financial losses beyond the cost of the original fabric.
11. How Manufacturers Can Reduce Spirality
Select Suitable Yarn
Choose yarn with appropriate torque characteristics and consistent specifications.
Optimize Knitting Conditions
Maintain controlled stitch length, yarn feeding and take-down tension.
Select an Appropriate Fabric Construction
Where dimensional stability is critical, evaluate more structurally balanced constructions when suitable for the garment.
Control Dyeing and Finishing
Avoid unnecessary fabric distortion during wet processing and finishing.
Apply Suitable Heat Setting
For polyester fabrics, use validated heat-setting conditions appropriate to the material and garment application.
Allow Controlled Relaxation
Follow an established fabric-relaxation procedure before cutting.
Conduct Wash Testing
Test representative fabric or garment samples before bulk production.
Maintain Production-Lot Consistency
Avoid mixing fabrics with different structural or finishing characteristics within the same garment order.
12. Can Spirality Be Completely Removed?
Not always.
The possibility of reducing spirality depends on its underlying cause.
Some distortion caused by processing tension may be reduced through suitable relaxation and finishing.
However, severe torque-related spirality originating from yarn characteristics or knitted construction can be difficult to eliminate completely.
Once fabric has been cut and stitched into garments, correction becomes more complicated.
This is why preventive quality control is generally more effective than attempting to repair finished garments.
13. What Should Bulk Fabric Buyers Check Before Ordering?
For clothing brands and garment manufacturers sourcing polyester knitted fabric, the following checks are useful.
Fabric construction: Identify whether the material is single jersey, interlock, pique or another knit.
Yarn specification: Confirm yarn type, denier, filament count and composition where relevant.
Dimensional stability: Request appropriate shrinkage and distortion test results.
Wash performance: Evaluate representative samples after repeated laundering.
Lot consistency: Confirm that supplied fabric matches the approved sample.
Intended application: Consider whether the fabric will be used for fitted garments, oversized T-shirts, uniforms or sportswear.
For large orders, approving fabric based only on an unwashed swatch can create unnecessary production risk.
14. Why GSM Alone Cannot Predict Spirality
GSM refers to the mass of fabric per square metre.
It is an important specification for evaluating fabric weight.
However, GSM does not directly reveal:
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Yarn torque.
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Loop inclination.
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Knitting-machine configuration.
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Fabric relaxation behaviour.
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Heat-setting effectiveness.
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Garment twisting after washing.
Two polyester fabrics with identical GSM values can therefore exhibit different levels of spirality.
Buyers should evaluate dimensional stability independently of fabric weight.
15. Frequently Asked Questions
Why does my polyester T-shirt twist after washing?
The twisting may result from fabric spirality, residual manufacturing tension, cutting misalignment or sewing-related distortion. Wash testing and fabric inspection can help identify the cause.
Is spirality a fabric defect?
Spirality becomes a quality defect when the measured distortion exceeds the buyer's agreed acceptance criteria or makes the garment unsuitable for its intended use.
Can heat setting prevent polyester spirality?
Appropriate heat setting can improve dimensional stability and reduce certain residual stresses, but it cannot guarantee elimination of spirality caused by unsuitable yarn or fabric construction.
Is single jersey more prone to spirality than interlock?
Certain single jersey constructions are generally more susceptible to torque-related distortion because of their relatively unbalanced loop structure. Actual performance depends on yarn and processing conditions.
Does higher GSM mean lower spirality?
No. Higher GSM does not automatically provide better resistance to spirality. Yarn torque, construction and finishing are more directly relevant.
Can spirality happen without shrinkage?
Yes. A garment can maintain approximately the same dimensions while its seams rotate or its panels become distorted.
Is polyester-Lycra resistant to spirality?
Not necessarily. Elastane changes the fabric's stretch and recovery behaviour, but spirality still depends on construction, yarn characteristics and processing.
Conclusion
Spirality is a technical fabric problem that can significantly affect the appearance and performance of polyester knitted garments.
A T-shirt may have the correct GSM, colour, width and stitching quality but still develop twisted seams after washing.
The underlying causes can include yarn torque, circular-knitting geometry, stitch length, residual tension, fabric construction and finishing conditions.
For garment manufacturers, the most effective approach is to evaluate dimensional stability before bulk cutting and production.
For fabric buyers, understanding spirality helps identify quality risks that cannot be detected through price or GSM comparisons alone.
At Walrus – Yes India Can, we supply a wide range of polyester knitted fabrics for T-shirts, sportswear, uniforms, casualwear and garment manufacturing.
Explore our fabric collections and discuss your bulk sourcing requirements with our team.
Website: https://www.yesindiacan.in/
Contact: +91 90420 77722
