FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION

(See section 10, rule 13)
1. Title of the invention: MANUFACTURING BIAS TYRE EXTRUDATES
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai, Maharashtra 400 030, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, bias tyres. More
specifically, the present subject matter relates to approaches for manufacturing bias tyre extrudates.
BACKGROUND
[0002] A tyre is a rubber covering for enclosing a wheel of a vehicle. The
tyre enables soft contact between the wheel and road. The tyre may include a carcass casing and a tyre extrudate arranged over the carcass casing. The tyre extrudate may form tread and sidewalls of the tyre. In an example, the tyre extrudate may be made of a plurality of plies, wherein the plurality of plies may be arranged in a defined manner. To such an end, based on a manner of arrangement of the plurality of plies, the tyre may be classified as, for example, radial tyre or bias tyre. In an example, the plurality of plies may be arranged at a pre-defined angle in an overlapping manner to form the bias tyre. As would be understood, the overlapping arrangement of the plurality of plies in the bias tyre may result in interdependent tread and sidewalls.
BRIEF DESCRIPTION OF DRAWINGS
[0003] The following detailed description references the drawings,
wherein:
[0004] FIG. 1 illustrates a perspective view of an extruder for
manufacturing a bias tyre extrudate, as per an example;
[0005] FIG. 2 illustrates a front view of an extruder for manufacturing a
bias tyre extrudate, as per an example;
[0006] FIG. 3 illustrates a front view of an extruder for manufacturing a
bias tyre extrudate with reference to a transversal axis, as per an example; and

[0007] FIG. 4 illustrates a bias tyre extrudate, as per an example.
DETAILED DESCRIPTION
[0008] The present subject matter relates to manufacturing of tyres,
specifically, bias tyres. As is generally understood, tyre is a ring-shaped covering for a wheel, wherein the wheel may be used for providing traction to a vehicle. Examples of the vehicle include, but are not limited to, bicycle, motorcycle, car, bus, trucks, and so forth. The tyre may include a tyre extrudate, among other members of the tyre. Further, the tyre extrudate may form tread and sidewalls of the tyre. To such an end, the tread may be a covering about a circumference of the wheel. Further, the sidewalls may extent from both longitudinal sides of the tread towards rim of the wheel. The tread and the sidewalls may provide room for containment of compressed air within the tyre.
[0009] Further, a bias tyre extrudate may be made up of a plurality of plies
(or layers). Such plurality of plies may be arranged in a defined manner, with respect to each other, to form the bias tyre extrudate. In an example, the plurality of plies may be arranged at angles of approximately 30 degrees with respect to each other, in a criss-cross manner, to form the bias tyre extrudate. Such angular arrangement of the plurality of plies may cause overlapping in the plurality of plies. The overlapping of the plurality of plies may further cause interdependence of material for the tread and the sidewalls of the bias tyre extrudate.
[0010] As would be understood, a thick and rigid material is employed for
manufacturing the tread of the tyre in order to provide greater cut and wear resistance to the tyre. Due to interdependence of material for the tread and the sidewalls of the bias tyre extrudate, the tread and the sidewalls of the bias tyre extrudate may be manufactured using the same material. In other words, overlapping of the plurality of plies in the bias tyre extrudate necessitates deployment of a uniform material for the tread and the

sidewalls. To such an end, thick and rigid material may be used for forming the tread as well as the sidewalls in the bias tyre extrudate.
[0011] However, rigid sidewalls are not desirable in a tyre. In an example,
rigid nature of the sidewalls may hamper shock-absorbing ability of the sidewalls. Such rigid sidewalls of a bias tyre may also affect comfort while riding a vehicle. Additionally, the rigid sidewalls may deflect on experiencing a shock causing the tread to squeeze in and distort. Due to such squeezing of the tread, the tyre may hamper traction and may be prone to uneven wear of the tread. Further, cost of the thick and rigid material is typically high. Therefore, the use of thick and rigid material for the tread as well as the sidewalls in the bias tyre extrudate substantially increases the cost of the tyre.
[0012] The present subject matter provides an extruder for manufacturing
bias tyre extrudate. As is generally understood, the extruder may push a heated raw compound material through a die of fixed cross-section. To such an end, pushing the raw compound material through the die may create a desired shape of the raw compound material. Further, the raw compound material may be an elastomer material, such as natural rubber, synthetic rubber, or a combination thereof. As mentioned previously, the bias tyre extrudate may comprise a tread and sidewall portions for bias tyre. In one example, the bias tyre extrudate may be arranged over a core casing. For example, the core casing may comprise radial body extending between beads.
[0013] The extruder for manufacturing the bias tyres extrudate includes a
base. In an example, the base may constitute a groove. Further, a primary outlet may be located at a first longitudinal side of the base. In one example, the groove within the base may be V-shaped.
[0014] Further, a plurality of extrusion heads (referred to as extrusion
heads) may be arranged within the groove of the base to form a plurality of channels (referred to as channels). The extrusion heads may be solid blocks having an inverted-V shape. Moreover, the extrusion heads may be rigidly

attached within the base. In this regard, dowel holes may be provided within
the extrusion heads. Further, dowel holes within the extrusion heads may
be arranged over dowels, provided within the groove of the base.
[0015] In operation, elastomer material may be fed into the channels. In
an example, the elastomer material may be fed from top of respective inlets
of the channels. For example, the inlets of the channels may be in proximity
to a second longitudinal side of the base, wherein the second longitudinal
side is opposite to the first longitudinal side. Further, the elastomer material
may be in form of, for example, pellets. In an example, the elastomer
material having different composition may be fed to the plurality of channels.
[0016] In one example, the extrusion heads may be deployed within the
base. In such a case, three channels may be formed within the base, using the four extrusion heads. Additionally, outlets of the three channels may be arranged to converge at the primary outlet of the base. Further, a first, a second and a third elastomer material may be fed to a first, a second and a third channel, respectively. To such an end, the third channel may be arranged between the first and the second channels.
[0017] Returning to the present example, the elastomer material fed to
the channels of the extruder may be heated and then co-extruded to form a
bias tyre extrudate. Such bias tyre extrudate may comprise one or more
plies of the elastomer material arranged in an overlapping manner at a pre-
defined angle. In one example, a ply of the elastomer material may be
extruded through outlet of the channels. Further, each of the plies of the
elastomer material may have a pre-defined dimension. In an example, one
or more plies of the elastomer material is extruded and continuously
arranged in contact with each other to form a single bias tyre extrudate.
[0018] In an example, the arrangement of the extrusion heads within the
base may form a die for the co-extrusion of the elastomer material. Additionally, the extrusion heads may be arranged to define a specific dimension and shape for the die, that may have a cross-section of a desirable size for co-extrusion of the bias tyre extrudate. Subsequently, the

bias tyre extrudate may be manufactured for wheels of truck and non-truck sizes. In this regard, dimensions of the plurality of plies corresponding to the elastomer material and the dimensions of the die may be defined accordingly. Furthermore, the plurality of plies corresponding to the elastomer material may be co-extruded in a manner such that sidewalls of the bias tyre extrudate is made of one or more plies of an elastomer material (referred to as the third elastomer material) provided at a base layer of the bias tyre extrudate. The third elastomer material may be flexible in nature. Additionally, one or more plies of elastomer materials (referred to as the first elastomer material and the second elastomer material) arranged over the third elastomer material may form the tread of the bias tyre extrudate. The first elastomer material and the second elastomer material may be rigid in nature.
[0019] Thus, the present subject matter involves manufacturing of
economical co-extruded bias tyres extrudates having different composition for tread and the sidewalls. In one case, the bias tyre extrudate is manufactured using three compositions of elastomer materials. In this regard, the sidewalls are made of flexible elastomer material thereby ensuring comfort of ride. Further, the tread is made up of rigid and thick elastomer material thereby ensuring greater wear resistance. Additionally, the manufacturing of the bias tyre extrudate is not restricted for any size thereof. To such an end, the co-extrusion of the elastomer material may be performed to produce bias tyre extrudates of any size, for example, truck and non-truck sizes. Thus, enabling implementation for Light Commercial Vehicles (LCV), passenger vehicles, two-wheelers, three-wheelers, and so forth.
[0020] These and other aspects are further described in conjunction with
the accompanying figures FIGS. 1-4. The above examples are further described in conjunction with appended figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter. It will thus be appreciated that various arrangements that embody

the principles of the present subject matter, although not explicitly described or shown herein, may be devised from the description and are included within its scope. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components.
[0021] FIGS. 1 illustrates perspective views of an extruder 100 for
manufacturing a bias tyre extrudate, as per an example. As shown, the extruder 100 includes a base 102 for receiving an elastomer material. The base 102 may be provided with a groove within the base 102. In an example, the groove of the base 102 may be V-shaped, wherein a converging end of the V-shaped groove may extend along a length of the base 102. Further, a longitudinal axis 114 may extend along the converging end of the base 102.The base 102 further has a primary outlet 104 located at a first longitudinal side of the base 102. Further, a plurality of extrusion heads 106-1, 106-2, 106-3 and 106-4 (collectively referred to as extrusion heads 106) are deployed within the base 102. The extrusion heads 106 may be solid blocks having an inverted-V shape for precise adjustment within the groove of the base 102. In one example, the base 102 and the extrusion heads 106 may be manufactured using metal.
[0022] The extrusion heads 106 may be operatively arranged in an
inclined manner within the base 102. The inclined arrangement of the extrusion heads 106 with respect to a transversal axis 110 along a centre of the base 102 may form a plurality of channels 108-1, 108-2 and 108-3 (collectively referred to as channels 108). To such an end, the channels 108 may be formed within the base 102. Moreover, outlets 112-1, 112-2 and 112-3 (collectively referred to as outlets 112) of the channels 108 are made to converge at the primary outlet 104 of the base 102. In an example, a

plurality of dowel heads may be provided within the extrusion heads 106 for rigidly fixing the extrusion heads 106 within the base 102.
[0023] In operation, the arrangement of the extrusion heads 106 within
the base 102 may form a die for co-extrusion of an elastomer material. In this regard, the elastomer material may be fed to the channels 108, via respective inlets. In an example, the elastomer material may be heated and further extruded through the outlets 112 of the channels 108. In an example, one or more plies of the elastomer material may be extruded through the outlets 112 of the channels 108. Such one or more plies of the elastomer materials may be arranged in contact with each other in an overlapping manner to form the bias tyre extrudate. The extrusion heads 106 may be arranged in an inclined manner with respect to the transversal axis 110. The transversal axis 110 may be perpendicular to the longitudinal axis 114, along a centre of the base 102.
[0024] The first extrusion head 106-1 and the second extrusion head 106-
2 are arranged at a first side of the transversal axis 110, and the third extrusion head 106-3 and the fourth extrusion head 106-4 are arranged at a second side of the transversal axis 110. To such an end, the first extrusion head 106-1 and the second extrusion head 106-2 are arranged opposite to each other to form a first channel 108-1 therebetween. The first extrusion head 106-1 and the second extrusion head 106-2 may be arranged such that an outlet 112-1 of the first channel 108-1 near the first longitudinal side of the base 102 is inclined towards the transversal axis 110. Similarly, the third extrusion head 106-3 and the fourth extrusion head 106-4 are arranged opposite to each other to form a second channel 108-2, wherein an outlet 112-2 of the second channel 108-2 near the first longitudinal side of the base 102 is inclined towards the transversal axis 110. Furthermore, a third channel 108-3 is formed between the second extrusion head 106-2 and the third extrusion head 106-3 that extends along the transversal axis 110. In this regard, the first channel 108-1 and the second channel 108-2 forms a V configuration with the transversal axis 110 along the centre of the base

102. Additionally, the third channel 108-3 is arranged along the transversal axis 110 in a manner that the third channel is in between the first channel 108-1 and the second channel 108-2.
[0025] In an example, the first channel 108-1, the second channel 108-2
and the third channel 108-3 may converge near the first longitudinal side to extend towards the primary outlet 104, in order to form the outlets 112-1, 112-2 and 112-3, respectively. Moreover, an inlet of the channels 108 may be near a second longitudinal side of the base 102, wherein the second longitudinal side may be opposite to the first longitudinal side.
[0026] In operation, a first elastomer material may be fed to the first
channel 108-1 via inlet thereof. Similarly, a second elastomer material may be fed to the second channel 108-2 and a third elastomer material may be fed to the third channel 108-3, via the respective inlets. To such an end, the first, the second and the third elastomer materials may have different rubber compositions. The first, the second and the third elastomer materials may be manufactured using, for example, natural rubber, synthetic rubber, carbon black, silica, fabric, and so forth. Pursuant to present subject matter, the third elastomer material may be flexible. Moreover, the first and the second elastomer material may be rigid in nature. In a manner as described above, the one or more plies of the first, the second and the third elastomer materials may be extruded through the outlets 112 of the channels 108. Subsequently, the bias tyre extrudate may be co-extruded through the primary outlet 104.
[0027] Continuing further, one or more plies of the third elastomer
material, having a first width may be extruded through the third channel 108-3. The one or more plies of the third elastomer material may form a base layer of the bias tyre extrudate to be manufactured. Thereafter, one or more plies of the second elastomer material extruded through the second channel 108-2 may be arranged over a portion of the one or more plies of the third elastomer material. In this regard, a width of the one or more plies of the second elastomer material may be less than the first width of the one or

more plies of the third elastomer material. Moreover, the one or more plies of the second elastomer material arranged over the third elastomer material may be aligned longitudinally along a centre thereof. In a similar manner, one or more plies of the first elastomer material extruded through the first channel 108-1 may be arranged over a portion of the one or more plies of the second elastomer material. Such arrangement of the one or more plies of the first, the second and the third elastomer materials may be performed in a continuous manner to co-extrude the bias tyre extrudate. The first, the second and the third elastomer materials may be further co-extruded through the primary outlet 104 of the extruder 100.
[0028] In an example, a length of the base 102 may be in a range of about
700 mm to 850 mm. Further, a depth of the base 102 may be in a range of
10 mm to 20 mm; and a width of the base 102 may be in a range of 60 mm
to 70 mm. The primary outlet 104 may be an opening through which the bias
tyre extrudate is extruded out of the extruder 100. In an example, a width of
the primary outlet 104 may be in a range of 200 mm to 850 mm.
[0029] FIG. 2 illustrates a front view of an extruder 100 for manufacturing
a bias tyre extrudate, as per an example. As mentioned previously, the extruder 100 comprises a base 102, wherein the base 102 comprises a groove (not shown in FIG. 2) within the base thereof. The groove may be V-shaped. The base 102 may have a primary outlet 104 at a first longitudinal side 202 thereof. Further, a plurality of extrusion heads (not shown in FIG. 2) may be operatively deployed within the groove of the base 102, in order to form a plurality of channels 108-1, 108-2 and 108-3 (collectively referred to as channels 108).
[0030] In an example, the plurality of extrusion heads are solid V-shaped
blocks. To such an end, a first extrusion head (such as the first extrusion head 106-1) and a second extrusion head (such as the second extrusion head 106-2) may be arranged opposite to each other in a manner such that they form a V-shape with an open apex. In this regard, a first channel, such as the first channel 108-1 may be formed between the first extrusion head

106-1 and the second extrusion head 106-2. Moreover, the open apex of the arrangement of the first extrusion head 106-1 and the second extrusion head 106-2 may form an outlet (such as the outlet 112-1) converging at the primary outlet 104 of the base 102. In an example, such arrangement of the first and the second extrusion heads 106-1 and 106-2 may be at a first side of a transversal axis 110. Moreover, the first and the second extrusion heads 106-1 and 106-2 are arranged in an inclined manner with respect to the transversal axis 110, in a manner such that open apex of the arrangement is inclined towards the transversal axis 110.
[0031] In a similar manner, a third extrusion head (such as the third
extrusion head 106-3) and a fourth extrusion head (such as the fourth extrusion head 106-4) may be arranged opposite to each other at a second side of the transversal axis 110 to form the second channel 108-2. Additionally, open apex of the arrangement of the third extrusion head 106-3 and the fourth extrusion head 106-4 may form an outlet (such as the outlet 112-2) converging at the primary outlet 104 of the base 102.
[0032] Furthermore, the second extrusion head 106-2 and the third
extrusion head 106-3, arranged at first side and second side, respectively,
of the transversal axis 110 also forms a V-shape with respect to each other.
To such an end, the third channel 108-3 may be formed between the second
and the third extrusion heads 106-2 and 106-3. Moreover, open apex of the
arrangement of the second extrusion head 106-2 and the third extrusion
head 106-3 may form an outlet (such as the outlet 112-3) converging at the
primary outlet 104 of the base 102. In an example, the converging outlets
may form a nozzle for extruding respective elastomer material therethrough.
[0033] FIG. 3 illustrates a front view of an extruder 100 for manufacturing
a bias tyre extrudate with reference to a transversal axis 110, as per an example. In an example, the front view may correspond to a first side of the transversal axis 110. As mentioned previously, a first extrusion head 106-1 and a second extrusion head 106-2 may be arranged at the first side of the transversal axis 110 to form a first channel therebetween. As shown a

plurality of dowel holes 302-1 and 302-2 are provided within the first extrusion head 106-1. Similarly, a plurality of dowel holes 302-3 and 302-4 are provided within the second extrusion head 106-2. Pursuant to the present subject matter, the plurality of dowel holes 302-1, 302-2, 302-3 and 302-4 (collectively referred to as dowel holes 302) may enable rigid arrangement of the first extrusion head 106-1 and the second extrusion head 106-2 within the base 102. In an example, the dowel heads 302 may be inserted over dowels of complimentary shapes provided within the base 102. In one example, a depth of the dowel heads 302 may be in a range of 5 mm to 15 mm.
[0034] The first extrusion head 106-1 and the second extrusion head 106-
2 are arranged in an inclined manner with respect to the transversal axis 110 as well as a longitudinal axis 114. In this regard, sides of the first and the second extrusion heads 106-1 and 106-2, that are in contact with a first longitudinal side 304 of the base 102, may be inclined towards the transversal axis 110. Subsequently, sides of the first and the second extrusion heads 106-1 and 106-2, that are in contact with a second longitudinal side 306 of the base 102, may be inclined away from the transversal axis 110. Furthermore, an angle of inclination of the first and the second extrusion heads 204-1 and 204-2, with respect to the transversal axis 110 may be in a range of 10 degrees to 30 degrees.
[0035] FIG. 4 illustrates a bias tyre extrudate 400, as per an example. The
bias tyre extrudate 400 may be manufactured by an extruder (such as the extruder 100). As described previously, an elastomer material may be fed to channels (such as the channels 108) in the extruder 100. Further, one or more plies corresponding to the elastomer material, extruded through the channels 108, may be arranged in an overlapping manner. Subsequently, a plurality of plies of the bias tyre extrudate may be arranged in an angular manner to form the bias tyre extrudate 400. In an example, the plurality of plies of the bias tyre extrudate 400 may be arranged at an angle of 30 degrees, with respect to each other.

[0036] In operation, a first elastomer material 402, a second elastomer
material 404 and a third elastomer material 406 may be co-extruded through a primary outlet (such as the primary outlet 104) of the extruder 100. In an example, one or more plies of the third elastomer material 406, having a first width, may be extruded through a third channel (such as the third channel 108-3). The one or more plies of the third elastomer material 406 may form a base layer of the bias tyre extrudate 400 to be manufactured. Thereafter, one or more plies of the second elastomer material 404 extruded through a second channel (such as the second channel 108-2) may be arranged over a portion of the one or more plies of the third elastomer material 406. In this regard, a width of the second elastomer material 404 may be less than the first width of the third elastomer material 406. Moreover, the second elastomer material 404 may be aligned longitudinally along a centre of the third elastomer material 406. In a similar manner, one or more plies of the first elastomer material 402 extruded through a first channel (such as the first channel 108-1) may be arranged over a portion of the second elastomer material 404.
[0037] Additionally, a width of the first elastomer material 402 is less than
the first width of the third elastomer material 406 as well as the width of the second elastomer material 404. Subsequently, extensions 406-1 and 406-2 of the one or more plies of the third elastomer material 406 may extend outwards from each longitudinal side of the first 402 and the second 404 elastomer materials. In an example, the third elastomer material 406 may be a flexible rubber material, whereas the first elastomer material 402 and the second elastomer material 404 may be rigid rubber materials. Such arrangement of the one or more plies of the first 402, the second 404 and the third 406 elastomer materials may be performed in a continuous manner to co-extrude the bias tyre extrudate 400.
[0038] Once the bias tyre extrudate 400 is manufactured by co-extruding
the first 402, the second 404 and the third 406 elastomer materials, it may now be arranged to form a pneumatic bias tyre. In this regard, the bias tyre

extrudate 400 may be arranged over an outer circumferential side of a carcass layer (not shown in FIG. 4). The bias tyre extrudate may be arranged over the carcass layer in a manner such that the extensions 406-1 and 406-2 of the third elastomer material 406 forms sidewalls of the pneumatic bias tyre. Further, the portion of the third elastomer material 406 over which the second 404 and the first 402 elastomer material is deployed, is arranged to form tread of the pneumatic bias tyre. In this regard, the second elastomer material 404 forms a cap of the tread of the pneumatic bias tyre while the first elastomer material 402 forms a cushion of the tread of the pneumatic bias tyre.
[0039] As would be understood, the carcass layer may extend between a
first and a second bead portion. In an example, one or more steel belts may further be arranged between the outer circumferential side of the carcass layer and the bias tyre extrudate 400. For example, a green tyre comprising the carcass layer, the one or more steel belts and the bias tyre extrudate 400 may then be cured to form the pneumatic bias tyre.
[0040] Although examples for the present disclosure have been
described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

I/We Claim:
1. An extruder for manufacturing a bias tyre extrudate, the extruder
comprising:
a base having a plurality of channels for receiving an elastomer material, and a primary outlet located at a first longitudinal side of the base; a plurality of extrusion heads, deployed within the base, wherein
the plurality of extrusion heads is operatively arranged in an inclined manner with respect to a transversal axis of the base, for forming the plurality of channels;
the elastomer material is fed to the plurality of channels, via respective inlets; and
outlets of the plurality of channels are arranged to converge at the primary outlet, wherein the elastomer material is co-extruded through the outlets to form the bias tyre extrudate.
2. The extruder as claimed in claim 1, wherein
a first extrusion head and a second extrusion head are arranged in parallel to form a first channel at a first side of the transversal axis, wherein the first and the second extrusion heads are inclined towards the transversal axis near the first longitudinal side;
a third extrusion head and a fourth extrusion head are arranged in parallel to form a second channel at a second side of the transversal axis, wherein the third and the fourth extrusion heads are inclined towards the transversal axis near the first longitudinal side; and
the second extrusion head and the third extrusion head inclined towards the transversal axis near the first longitudinal side and arranged at the first and the second side thereof, respectively, forms a third channel along the transversal axis.

3. The extruder as claimed in claim 1, wherein an angle between the plurality of extrusion heads and a longitudinal axis along a centre of the base is in a range of 20°C to 40°C.
4. The extruder as claimed in claim 1, wherein a width of the primary outlet is in a range of 200 mm to 850 mm.
5. The extruder as claimed in claim 1, wherein the plurality of extrusion heads is arranged to form three channels, wherein
a first elastomer material is fed to a first channel, a second elastomer material is fed to a second channel and a third elastomer material is fed to a third channel; and
the first, the second and the third elastomer material are co-extruded through outlets of the respective channels to form the bias tyre extrudate.
6. The extruder as claimed in claim 5, wherein
the third elastomer material is arranged as a base layer having a first width and the second and the first elastomer material are arranged over the third elastomer material, wherein a width of the second and the third elastomer material is smaller than the first width; and
a portion of the bias tyre preform comprising the first, the second and the third elastomer materials forms tread and portions of the third elastomer material extending outwards from the tread forms sidewalls
7. The extruder as claimed in claim 5, wherein the first and the second channels forms a V configuration with a transversal axis along a centre of the base, and the third channel is arranged along the transversal axis in a manner that the third channel is in between the first and the second channels.
8. A pneumatic bias tyre comprising:

a carcass layer extending between a first and a second bead portion; a bias tyre extrudate arranged on an outer circumferential side of the carcass layer, wherein
a bias tyre preform is manufactured by co-extruding a first, a second and a third elastomer material in such a manner that the third elastomer material is arranged as a base layer having a first width and the second and the first elastomer material are arranged over the third elastomer material, wherein a width of the second and the third elastomer material is smaller than the first width; and
a portion of the bias tyre preform comprising the first, the second and the third elastomer materials form tread and portions of the third elastomer material extending outwards from the tread forms sidewalls.
9. The pneumatic bias tyre as claimed in claim 8, wherein a diameter of the pneumatic bias tyre is in a range of 800 mm to 850 mm.
10. The pneumatic bias tyre as claimed in claim 8, wherein a width of the pneumatic bias tyre is in a range of 180 mm to 215 mm.