Influence of Coatings on the Durability and Friction of Clutch Systems in Motorsport

Dmytro Dekanozishvili

doi:10.37547/tajiir/Volume07Issue08-08

The American Journal of Interdisciplinary Innovations and Research

74

https://www.theamericanjournals.com/index.php/tajiir

Type

Original Research

PAGE NO.

74-80

DOI

10.37547/tajiir/Volume07Issue08-08

OPEN ACCESS

SUBMITED

28 July 2025

ACCEPTED

09 August 2025

PUBLISHED

21 August 2025

VOLUME

Vol.07 Issue 08 2025

CITATION

Dmytro Dekanozishvili. (2025). Influence of Coatings on the Durability and
Friction of Clutch Systems in Motorsport. The American Journal of
Interdisciplinary Innovations and Research, 7(8), 74

–

80.

https://doi.org/10.37547/tajiir/Volume07Issue08-08

COPYRIGHT

© 2025 Original content from this work may be used under the terms
of the creative commons attributes 4.0 License.

Influence of Coatings on
the Durability and Friction
of Clutch Systems in
Motorsport

Dmytro Dekanozishvili

Founder and CEO of Deka Clutches LLC Miami, USA

Abstract:

The article presents a comprehensive

analysis of the influence of surface coatings and
microtextures on the frictional characteristics and
durability of clutch components in professional
motorsport applications. The study is based on an
interdisciplinary approach that integrates engineering
tribology, materials science, and applied mechanics of
high-load transmission systems. Particular attention is
given to content and comparative analysis of both
domestic and international sources describing the
behavior of DLC coatings, PTFE-based composites, and
iron-based laser claddings under various friction
modes, thermal loads, and cyclic stresses. Critical
differences between coatings are identified in terms of
friction coefficient, wear volume, thermal stability, and
adhesion strength to the substrate. Based on empirical
data, a typology of coating applicability is proposed for
different motorsport disciplines, ranging from circuit
racing to rally and drag racing. Summary tables are
presented to reflect the operational properties of

coatings at temperatures up to 250 °C and under

boundary lubrication conditions. The necessity of
context-specific coating selection is substantiated,
taking into account track configuration, weight
constraints, and cooling requirements. Special
emphasis is placed on the role of microtextures in heat
distribution and contact stress regulation within the
clutch. This article will be of interest to design
engineers, motorsport specialists, friction system
developers, and surface engineering researchers
involved in the design of transmission components for
extreme operating conditions.

Keywords:

clutch, motorsport, coating, friction, wear,

DLC, PTFE, laser cladding, microtexture, thermal

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stability.

Introduction

Modern motorsport

—

both on the international stage

and

within

national

series

—

is

undergoing

a

technological shift driven by ever-higher demands on
powertrain efficiency, durability and sustainability.
Increasing loads on transmission components,
intensified thermal and mechanical operating regimes,
and the pursuit of weight reduction place the clutch at
the forefront of engineering attention as the primary
torque-transmission device [1]. Against this backdrop,
interest in surface-modification technologies

—

coatings

and texturing

—

has surged as a means to control

tribological behavior and extend component life.

A key challenge, emphasized in both academic and
applied literature, is reducing frictional losses while
preserving sufficient engagement force and minimizing
wear. Iron-based laser claddings, for example,
redistribute contact stresses and enhance thermal
stability within the clutch assembly [3]. Diamond-like
carbon (DLC) coatings and solid-lubricant phases such as
PTFE deliver consistent clutch performance at elevated
temperatures

and

under

boundary-lubrication

conditions [10]. Nanostructured coatings exhibit
exceptional resistance to frictional degradation,
lowering the risk of functional failure under extreme
load [7]. Empirical studies confirm that combining
microtexturing with advanced coatings creates a surface

“second skin” that adapts to racing conditions and

mitigates thermal damage [6].

Practical implementations of these surface-engineering
advances appear in GT3 and Formula SAE race cars,
where clutches endure maximum wear and fluctuating
load cycles. Laser microtexturing and tribologically
robust coatings enable teams to achieve repeatable
launch torque with minimal slip and clutch-disk
overheating.

Integrating functional coatings into clutch design
requires a deep understanding of friction mechanisms,

wear modes under racing conditions, and the coatings’

ability to withstand thermo-cyclic stresses and contact
vibrations. Such research is essential for developing the
technological solutions that ensure transmission
reliability under the most demanding motorsport
scenarios.

The aim of this study is to conduct a comprehensive
analysis of how coatings and microtextures affect the

tribological characteristics of racing-car clutches, to
identify patterns of friction-coefficient changes and
component life expectancy depending on surface
treatment, and to establish criteria for selecting
appropriate coatings for racing applications.

Materials and Methods

The methodological framework of this study sits at the
crossroads of engineering tribology, materials science
and applied motorsport mechanics, reflecting the
complexity of enhancing clutch wear resistance and
predictability under extreme loads. A systematic
content analysis of experimental and review articles
addressing the effects of surface textures and coatings
on friction performance and lifespan of clutch
assemblies served as the principal research tool.

Sources encompassed both fundamental and applied
engineering advances focused on highly stressed

interfaces. Of particular note is Tung’s review [5], which

summarizes how various surface coatings

—

including

diamond-like carbon (DLC), nitride systems and
aluminum thermal-spray layers

—

affect the frictional

behavior of powertrain components. Qiao et al. [3]
investigated the combined effects of laser cladding and
microtexturing on reducing dry friction and improving
wear resistance, outcomes critically important in racing
applications. Wu [7] demonstrated the efficacy of DLC
coatings under high-frequency mechanical loading and
their stability through thermo-cyclic overloads. Di et al.
[8] analyzed the spatial organization of microtextures on
road surfaces, providing transferable insights into
contact-pressure distribution for clutch disc interfaces.
Similarly, Ma [10] conducted experimental tests on
carbon-reinforced composites mated to steel surfaces,

modeling

the

“disc

-pressure-

plate”

interaction

characteristic of racing clutches. He et al. [9] examined
how surface-roughness parameters influence the
behavior

of

GCr15

bearing

steel,

informing

understanding of clutch-material thermo-mechanical
response under heating.

Additional emphasis

was placed on Tung’s work [6],

which links surface-architecture design to powertrain
reliability, and Wilkinson et al. [2], who evaluated laser-
generated biomimetic textures combined with PTFE-
based solid lubricants in boundary-lubrication scenarios.

The content analysis proceeded according to the
following scheme:

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The American Journal of Interdisciplinary Innovations and Research

1.

Classification of coating types (DLC, nitrides,
composites) and texture geometries (point, linear,
oriented) based on aggregated literature data;

2.

Comparative analysis of tribological metrics (friction
coefficient, wear rate, overheating resistance)
across operating regimes

—

dry, boundary and mixed

lubrication;

3.

Systematization of experimental findings on how
surface-treatment

methods

influence

clutch

durability and performance consistency under
racing conditions.

Visual schematics and tabular summaries from multiple
sources provided the basis for constructing an
integrated model of frictional interaction that
incorporates

texture

parameters

and

coating

composition. This model reconstructs the primary
relationships governing load distribution, heat

generation and wear as a function of surface treatment
and contact environment.

In sum, the research methodology relies on

systematic comparison, critical selection and conceptual
integration of published data, enabling identification of
robust engineering solutions to improve clutch
efficiency in motorsport applications.

Results

A comparative analysis of experimental data from
several studies was performed to systematize the
frictional behavior of coatings of various types, including
DLC, PTFE-based composites with microtextures and
iron-based laser claddings. The evaluation covers
performance under dry and boundary-lubrication
regimes, with emphasis on static and kinetic coefficients
of friction. Table 1 summarizes the behavior of each
coating under varied test conditions.

Table 1

–

Comparison of Friction Coefficients for Different Coatings (Compiled by the author based on

sources: [3], [5], [7], [10])

Coating Type

Friction Mode

Friction Coefficient (Static

/ Kinetic)

Change vs. Uncoated

Surface

Uncoated (Steel)

Dry

0.63 / 0.58

−

DLC

Dry

0.18 / 0.15

−70 %

Boundary

lubrication

0.10 / 0.08

−82 %

PTFE + Microtexture

Dry

0.24 / 0.21

−62 %

Boundary

lubrication

0.11 / 0.09

−80 %

Iron-based Laser

Cladding

Dry

0.36 / 0.33

−43 %

Boundary

lubrication

0.25 / 0.22

−62 %

PTFE-based

microtextured

composites

deliver

performance similar to DLC under boundary lubrication
but fall short in fully dry conditions. Iron-based laser
claddings yield a moderate friction reduction while
offering enhanced durability under peel-off loads [3],

[10].

Wear resistance was also compared at temperatures
representative of racing-clutch operation. Table 2
presents volumetric wear, microdamage observations

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and coating-substrate adhesion strength at 150 °C and 250 °C.

Table 2

–

Wear Resistance of Coatings at 150 °C and 250 °C (Compiled by the author based on sources:

[3], [5], [6], [7])

Coating Type

Temperature (°C)

Volumetric Wear

(mm³)

Microdamage

Adhesion

Strength

Uncoated

150

8.1

Significant

–

250

12.6

Critical

–

DLC

150

1.2

None

High

250

2.5

Slight

Stable

PTFE +

Microtexture

150

2.4

Minor

Moderate

250

4.9

Moderate

Iron-Based Laser

Cladding

150

3.3

Minor

High

250

5.7

Moderate

Stable

Nitride Coating

(TiN)

150

1.9

None

High

250

3.4

Slight

High

DLC coatings exhibit the lowest wear rates and strongest
adhesion across the temperature range. At 250 °C, only
DLC and nitride coatings remain operational without
critical damage. PTFE-composites perform well at
moderate temperatures but degrade at peak thermal
loads, limiting their use in high-heat zones. Iron-based
laser claddings demonstrate reliable bond strength and
moderate wear, making them suitable where lubrication
is unstable and contact pressures are elevated [5], [6].

These findings confirm that coating selection must be
guided by the expected thermal regime and contact
conditions. DLC and nitride coatings emerge as universal
solutions, while PTFE-based composites are best applied
where heat dissipation is optimal.

Discussion

The analysis of materials demonstrates that coating type
critically determines the development and stabilization
of friction under the high-temperature, high-load

conditions typical of motorsport clutch systems. Its
influence on the time-dependent evolution of the
friction coefficient and on clutch thermo-stability across
varying operating regimes is particularly significant.

Qiao’s work [3] reveals a marked contrast between

untreated surfaces and those modified by iron-based
laser cladding. Laser-clad coatings exhibit a smoother
rise in friction coefficient during initial contact and
reduced sensitivity to localized overheating. This
behavior is attributed to the formation of a stable oxide
layer and the increased microhardness of the clad layer.
Diamond-like carbon (DLC) coatings, by contrast, deliver
very low friction coefficients (0.08

–

0.18) and a

pronounced self-lubricating effect [7]. Their tribo-
chemical structure generates graphite-like fragments at
elevated temperatures, which redistribute across the
contact zone to form a boundary film that lowers
frictional resistance [5].

PTFE-based composites combined with microtexturing

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function similarly, as Ma [10] demonstrates. Here,
directed cooling is the key mechanism: textured micro-
channels efficiently extract heat from the contact area,
while the low-friction, low-conductivity PTFE acts as a
buffer, protecting the substrate from overheating.
Compared with DLC, PTFE textures exhibit lower
absolute wear resistance (see Table 2) but perform
better under frequent thermal cycling. Microtextured
coatings maintain reliable heat transfer between mating
surfaces, reducing the amplitude of temperature
fluctuations

—

a critical advantage when a racing clutch

alternates abruptly between throttle surges and heavy
braking.

Selecting an appropriate coating for racing applications
cannot be divorced from the specifics of each
motorsport discipline, the severity of thermal and
impact loads, and the weight and service-life
requirements of the components. Table 3 summarizes
the key performance criteria that govern coating
suitability in professional racing environments.

Table 3

–

Summary Assessment of Coating Suitability for Racing Conditions (Compiled by the author

based on analysis: [5], [7], [9], [10])

Coating

Thermal Stability

Wear under

Impact Load

Coating Weight

Suitability for

F1/GT3

DLC

High

Medium

Low

Yes

Iron-Based Laser

Cladding

Medium

High

Medium

Yes, with effective

cooling

PTFE +

Microtexture

Low

Very low

No

DLC-based coatings, despite their higher cost, deliver
the optimal combination of thermal resistance and low
mass

—

an essential consideration in F1, where every

gram affects vehicle dynamics and handling [7]. By
contrast, iron-based laser claddings

—

valued for their

high strength and capacity to absorb impact loads

—

are

well suited to rally and circuit racing, where clutches
endure abrupt peak stresses [9]. However, their thermal
stability is more limited, and effective deployment
demands a robust cooling system and precise operating-
mode control, making them less universal for high-speed
series with narrow temperature tolerances.

PTFE-composite coatings with microtexturing, while
offering minimal weight and very low friction, cannot
withstand the thermal and mechanical demands of a
racing clutch

—

particularly at temperatures above 200

°C. Their use may therefore be confined to training or
test platforms operating under simplified load profiles
[10].

From an economic perspective, the resource intensity of
DLC deposition is partly offset by its extended service life

and

reduced

maintenance

costs

(fewer

disc

replacements and component repairs) [7]. Conversely,
PTFE-based coatings, though inexpensive to apply,
rapidly lose functionality, diminishing their cost-
effectiveness over a full lifecycle. Laser claddings occupy
an intermediate position: they incur significant
substrate-preparation and heat-treatment expenses,
yet deliver reliable performance under extreme
conditions [5].

Accordingly, the most practical approach in motorsport
is a context-driven selection of coating technology:

●

For F1 and GT3: DLC coatings, for their

light weight and thermal stability;

●

For rally: iron-based laser claddings,

paired with enhanced cooling;

●

For drag racing: potential use of hybrid

systems featuring PTFE elements during launch phases,
albeit with restricted cycle life.

These conclusions emphasize the imperative of

integrating tribological, thermal and structural criteria

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when engineering clutch systems for professional
motorsport.

Conclusion

The present study has confirmed the critical importance
of surface coatings as a decisive factor influencing the
tribological performance and durability of clutch
assemblies in motorsport. It has been shown that the
choice of coating type can dramatically alter the friction
coefficient and determine wear behavior, thermal
stability and operational reliability of the clutch under
extreme loads.

A comparative analytical review of DLC films, iron-based
laser claddings and micro-textured composites
demonstrated that no single solution suits every racing
discipline. Low-friction coatings such as PTFE fail to
deliver the necessary heat resistance and defect-
tolerance. In contrast, DLC structures ensure stable
friction properties and wear resistance across a wide
temperature range, making them the preferred option
for circuit racing and Formula classes. Laser-clad
coatings offer high impact strength but demand a
carefully engineered cooling system and mass-control
strategy.

Special emphasis was placed on the influence of surface
microtexture on clutch behavior. It was found that the
orientation and scale of textured elements can govern
heat dissipation and contact-stress distribution, yielding
more predictable clutch engagement during transient
regimes. This insight paves the way for deliberate
surface tuning to match specific track characteristics,
coating types and transmission configurations.

Thus, clutch surface modification should be viewed not
as an isolated engineering feature but as an integral

component of a race car’s strategic setup. The findings

lay the groundwork for adaptive transmission-
component configurations tailored to competition
conditions, climate and dynamic requirements. Future
research should focus on developing multifunctional
coatings that combine low friction, high mechanical
strength and controllable thermophysical properties.

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