Abstract:
A tire tread is provided that in an unworn state includes one or more tread features having a layer of a relatively softer, higher grip rubber material. This layer is formed from a first rubber composition that is provided as a skim or relatively thin layer at the contact surface of the tread feature. This skim provides the grip needed as the tire starts to warm up but can then wear away after an initial period of use so that the contact surface is eventually formed from a second rubber composition. This second rubber composition, in turn, provides the desired level of grip and acceptable wear at the higher temperatures that occur as the tire heats up from use. The layer of skim can be profiled depending upon the application and performance characteristics needed.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present disclosure relates generally to a tire having a layer of higher grip rubber material on one or more tread features. 
       BACKGROUND OF THE INVENTION 
       [0002]    The tread of a tire may be equipped with one more structural features for the purpose of e.g., improving traction and/or rolling resistance performance over a variety of different conditions. For example, grooves, incisions, and other elements may be formed into the tread. The orientation of such features may be specifically determined to provide certain performance characteristics. 
         [0003]    Traction performance is not determined solely by such structural features, however. The composition of the materials used to manufacture the tread can also affect traction performance, rolling resistance, or both. Such is particularly true with ultra-high performance (UHP) tires such as racing tires that may be used during relatively high speed and high torque conditions. 
         [0004]    For example, relatively softer rubber compositions (i.e. having a lower elastic modulus and/or lower Shore Hardness) have been developed that can provide higher grip under UHP conditions. Unfortunately, such softer rubber compositions also wear quickly. Decreasing the softness of the rubber compositions can improve wear but a trade-off occurs because generally such decrease will also result in less grip. Accordingly, some conventional constructions have proposed rubber compositions that attempt to compromise this trade-off over the useful life of the tread but sacrifices are necessarily made to either grip, wear, or both. 
         [0005]    Constructions have also been proposed for non-UHP tires that utilize different rubber compositions within the tread over its useful life. Such have been proposed, for example, to improve wet traction as the tread wears over its useful life and thereby reduces the depth of grooves and channels otherwise available to evacuate water from the contact patch. The tread is designed so that as it wears and the tread depth decreases, the contact surface of the tire is increasingly formed by a relatively softer rubber composition that provides increased wet traction. Unfortunately, for UHP applications, such use of softer, higher grip compositions at a deeper tread depth can lead to blistering and other problems that negatively affect performance as the temperature of the tread increases during use. 
         [0006]    Accordingly, a tire that can provide improved grip and wear performance particularly in UHP applications would be useful. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a tire tread that in an unworn state includes one or more tread features that have a layer of a relatively softer, higher grip rubber material. This layer is formed from a first rubber composition that is provided as a skim or relatively thin layer at the contact surface of the tread feature. This skim provides the grip needed as the tire starts to warm up but can then wear away after an initial period of use so that the contact surface is eventually formed from a second rubber composition. This second rubber composition, in turn, provides the desired level of grip and acceptable wear at the higher temperatures that occur as the tire heats up from use. The layer of skim can be profiled depending upon the application and performance characteristics needed. Additional objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
         [0008]    In one exemplary embodiment, the present invention provides a tire adapted for mounting onto a rim of a vehicle. The tire has a predetermined orientation for mounting on the vehicle such that the tire defines an outboard shoulder and an inboard shoulder spaced apart along an axial direction of the tire with the inboard shoulder located axially inward of the outboard shoulder relative to the vehicle. The tire includes a tread having a thickness along a radial direction of the tire with the tread defining a plurality of discrete tread features that are separated from each other along the axial direction by grooves. In an unworn state along the axial direction from the outboard side to the inboard side, the tread features include an outboard tread feature positioned along the outboard shoulder of the tire and having an outboard contact surface. The outboard tread feature includes a first layer constructed from a first rubber composition forming at least part of the outboard contact surface and a second layer wholly supporting the first layer of the outboard tread feature and constructed from a second rubber composition. A first interior tread feature is positioned axially inward of the outboard tread feature and has a first interior contact surface. The first interior tread feature includes a first layer constructed from the first rubber composition and forming part of the first interior contact surface, and a second layer wholly supporting the first layer of the first interior tread feature and constructed from a second rubber composition. The second layer of the first interior tread feature also forms part of the first interior contact surface. An inboard tread feature is positioned along the inboard shoulder of the tire and has an inboard contact surface. The first rubber composition has an elastic modulus that is about eighty percent or less of the second rubber composition. 
         [0009]    In another exemplary embodiment, the present invention provides a tire adapted for mounting onto a rim of a vehicle. The tire has a predetermined orientation for mounting on the vehicle such that the tire defines an outboard shoulder and an inboard shoulder spaced apart along an axial direction of the tire with the inboard shoulder located axially inward of the outboard shoulder relative to the vehicle. The tire includes a tread having a thickness along a radial direction of the tire with the tread defining a plurality of discrete tread features that are separated from each other along the axial direction by grooves. In an unworn state along the axial direction from the outboard side to the inboard side, the tread features include an outboard tread feature positioned along the outboard shoulder of the tire and having an outboard contact surface. The outboard tread feature includes a first layer having a first rubber composition forming at least part of the outboard contact surface; and a second layer wholly supporting the first layer of the outboard tread feature and including a second rubber composition. A first interior tread feature is positioned axially inward of the outboard tread feature and has a first interior contact surface. The first interior tread feature includes a first layer having a third rubber composition and forming part of the first interior contact surface; and a second layer wholly supporting the first layer of the first interior tread feature and including the second rubber composition. The second layer of the first interior tread feature also forms part of the first interior contact surface. An inboard tread feature is positioned along the inboard shoulder of the tire and has an inboard contact surface. The first rubber composition and the third rubber composition each have an elastic modulus that is about eighty percent or less of the second rubber composition. 
         [0010]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0012]      FIG. 1  illustrates a cross-sectional view of an exemplary embodiment of a tire and tire tread of the present invention. The view in this figure as well as all of the following figures can also be referred to as a radial cross-section view, which is a cross-section taken in a plane that is parallel to both axial direction A and radial direction R. 
           [0013]      FIG. 2  illustrates a radial cross-section view of an exemplary embodiment of a tire tread of the present invention. 
           [0014]      FIG. 3  provides another radial cross-section view of an exemplary embodiment of a tire tread of the present invention. 
           [0015]      FIGS. 4 ,  5 ,  6 ,  7 , and  8  each provide radial cross-section views of exemplary embodiments of tread features of the present invention. 
       
    
    
       [0016]    All figures depict an exemplary tread in an unworn condition. 
       DETAILED DESCRIPTION 
       [0017]    For purposes of describing the invention, reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0018]    As used herein: 
         [0019]    “Modulus of elasticity” or “elastic modulus” of a rubber composition means the secant modulus of extension obtained in fraction according to ASTM standard D 412 of 1998 (specimen “C”): The secant modulus apparent at 10% elongation, denoted “MA10” and expressed in MPa (standard temperature and hygrometric conditions according to ASTM standard D 1349 of 1999) is measured in a second elongation (i.e. after a cycle of accommodation). This modulus of elasticity may be differentiated from the moduli of elasticity obtained in compression and of which the values generally have no connection with the moduli obtained in extension. 
         [0020]    “Contact surface” refers to the area of a tire tread or particular tread feature in contact with a planar ground or road surface when the tire is properly mounted (and properly inflated if the tire is pneumatic). 
         [0021]    “Unworn” refers to the tire&#39;s condition before wear occurs i.e. before any use occurs that would remove material from the contact surface. All figures in the present application depict the tread or a tread feature in the unworn condition. 
         [0022]    The inventors have determined that improved grip and wear performance, particularly in UHP applications, can be achieved by positioning and profiling relatively softer (i.e. lower modulus of elasticity and/or lower Shore Hardness) and relatively harder (i.e. higher modulus of elasticity and/or higher Shore Hardness) rubber compositions in a particular configuration on a tire tread. In general, harder and more wear resistant rubber compositions are provided toward the outboard edge of a tread feature particularly interior tread features at or along the outboard side of the centerline of the tire—while softer rubber compositions having better grip for traction are provided toward the inboard side to avoid exposure to extreme stress and strains that can cause high wear rate. In addition, depending upon the position of the tread feature—particularly interior tread features—the profile of the softer rubber composition along a radial cross-section can be configured to further enhance effectiveness. 
         [0023]    Exemplary embodiments will now be more specifically described for purposes of further explaining the present invention. 
         [0024]      FIG. 1  illustrates a radial cross-sectional view of an exemplary embodiment of a tire  100  of the present invention in an unworn condition while  FIG. 2  illustrates a tread portion  106  of tire  100 . Tire  100  will be used for purposes of description. However, using the teachings disclosed herein, it will be understood that the present invention is not limited to the particular tire construction—including e.g., profile or type—shown in  FIG. 1  as other constructions may be used as well. 
         [0025]    Tire  100  is adapted for mounting on a rim of a wheel of a vehicle according to a predetermined direction for mounting. More specifically, tire  100  includes an outboard shoulder  102  mounted away from the body of the vehicle and an inboard shoulder  104  that is mounted toward, or along the same side of tire  100  as, the body of the vehicle. Tire  100  defines axial direction A that is parallel to the axis of rotation of the tire during travel and a radial direction R that is orthogonal to axial direction A. As used herein, axially inward refers to the direction illustrated with arrow AI, and is a direction going from the outboard shoulder  102  towards the inboard shoulder  104  along axial direction A as shown. 
         [0026]    For this exemplary embodiment, tire  100  includes a pair of bead cores  120  and  122  that are separated along axial direction A. The ends of a carcass ply  126  are wrapped around each bead core  120  and  122 . The carcass ply  126  extends between the bead cores and through opposing sidewalls  116 ,  118  and tread portion  106 . Crown plies  128  and  130  can be provided radially inward of tread portion  106  and radially outward of carcass ply  126 . Again, other tire constructions may be used with the present invention as well. 
         [0027]    Tread  106  has a thickness along radial direction R and defines discrete tread features  132 ,  134 ,  136 ,  138 , and  140 . These discrete tread features are formed and separated from each other along the axial direction by a plurality of grooves  108 ,  110 ,  112 , and  114 , respectively. While tire  100  is shown to include tread features  132 ,  134 ,  136 ,  138 , and  140  illustrated in the form of ribs, the present invention may also be used with a tread having a different number of ribs as well as a tread formed from tread blocks instead of ribs. The tread features include an outboard tread feature  132  positioned along outboard shoulder  102  and an inboard tread feature  140  positioned along inboard shoulder  104 . 
         [0028]    A plurality  142  of interior tread features are provided between, or interior to, the outboard and inboard tread features  132  and  140 , respectively. The interior tread features making up plurality  142  can be referred to relative to their position with respect to outboard tread feature  132  along the axially inward direction AI. Accordingly, plurality  142  includes a first interior tread feature  134  that is axially inward of outboard tread feature  132 , a second interior tread feature  136  that is axially inward of first interior tread feature  134 , and a third interior tread feature  138  that is axially inward of second interior tread feature  136 . First interior tread feature  134  is adjacent to outboard tread feature  132 —meaning that another interior tread feature is not positioned between them. Similarly, second interior tread feature  136  is adjacent to first interior tread feature  134 , third interior tread feature  138  is adjacent to second interior tread feature  136  and inboard tread feature  140 . Interior tread features  134 ,  136 , and  138  provide first interior contact surface  146 , second interior contact surface  148 , and third interior contact surface  150 , respectively, in this exemplary embodiment. 
         [0029]    While three interior tread features are shown for this exemplary embodiment of tire  100 , it should be understood that the present invention includes tires having one, two, four or more interior tread features as well. Further, although shown as equal in  FIGS. 1 through 3 , the width along axial direction A of the interior tread features  134 ,  136 , and  138  can be varied between such features. 
         [0030]      FIG. 2  provides a closer, radial cross-section view of the exemplary tread  106  of  FIG. 1  while  FIG. 4  provides a closer, radial cross-section view of outboard tread feature  102 . As shown in  FIGS. 2 and 4 , outboard tread feature  132  has an outboard contact surface  144 . Outboard tread feature  132  is constructed from a first layer  132   a  that includes a first rubber composition and a second layer  132   b  that includes a second rubber composition. First layer  132   a  is wholly supported by second layer  132   b.  As used herein, for treads having a depth of about 6.5 mm or greater at the centerline C/L, “wholly supported” means that the first layer forms at least part of the outboard contact surface when tire  100  is in the unworn condition and that the largest thickness T along radial direction R of the first layer is no more than about twenty percent of the of thickness along the radial direction R of the second layer. For treads having a depth of less than about 6.5 mm at the centerline C/L, “wholly supported” means that the first layer forms at least part of the outboard contact surface when tire  100  is in the unworn condition and that the largest thickness T along radial direction R of the first layer is no more than about fifty percent of the of thickness along the radial direction R of the second layer. Accordingly, first layer  132   a  is formed as a skim—i.e. a thin layer  132   a  of the first rubber composition that forms at least a portion  144   a  of the outboard contact surface  144  for outboard tread feature  132 . 
         [0031]    For this exemplary embodiment, first layer  132   a  forms most or all of the outboard contact surface  144  of outboard tread feature  132 . In other exemplary embodiments, the amount of first layer  132   a  forming contact surface  144  may be less. Additionally, for this exemplary embodiment, the thickness T of first layer  132   a  along radial direction R is relatively uniform. However, in other embodiments, thickness T may vary such that first layer  132   a  has a profile along a radial cross-section that tapers along axial direction A. 
         [0032]      FIGS. 5 ,  6 , and  7  provide radial cross-section views illustrating exemplary embodiments of a tread feature that may be used for either first interior tread feature  134 , second interior tread feature  136 , or both. Each will now be described in turn using the reference numerals of the first interior tread feature  134  by way of example—it being understood that the embodiments of  FIGS. 5 ,  6 , and  7  can be used for either, or both, of the interior tread features  134  and  136 . More specifically, the exemplary embodiments of  FIGS. 5 ,  6 , and  7  can be used for interior tread features that are either at or to the outboard side of the centerline C/L of tire  100 . 
         [0033]    Beginning with  FIG. 5 , interior tread feature  134  provides an interior contact surface  146  that includes portion  146   a  and  146   b.  Interior tread feature  134  is constructed from a first layer  134   a  that includes a first rubber composition and a second layer  134   b  that includes a second rubber composition. First layer  134   a  is wholly supported by second layer  134   b  and is formed as skim on second layer  134   b.    
         [0034]    As shown in the radial cross-section view of  FIG. 5 , first layer  134   a  has a profile that increases in thickness T along the axially inward direction AI. First layer  134   a  has a bottom  156  that may be slightly concave (as shown) or linear. In either case, bottom  156  forms an overall angle α with the interior contact surface  146  as depicted with arrow P. Angle a may be, for example, in the range of about 10 degrees to about 30 degrees. 
         [0035]    For this exemplary embodiment, first layer  134   a  forms contact surface  146   a , which is nearly all of the interior contact surface  146 . In other embodiments, the amount of first layer  134   a  forming interior contact surface  146  may vary. As stated, the exemplary tread feature of  FIG. 5  may be used for either first interior tread feature  134 , second interior tread feature  136 , or both. As compared to a tire having only one contact surface  146  of either all soft, high-grip material ( 134   a ) or all hard, more wear resistant, but lower grip material ( 134   b ), there are a couple advantages. First, if the tread features ( 146 ,  148 ,  150 ) were comprised of only soft, higher-grip compound, the lack of a more rigid underlying support could lead to severe deformation in the tread features, which results in elevated tread-road surface shear and in a seriously high wear rate of two-to-three times faster than the embodiment with the high-grip tread skim combined with the more enduring and supportive underlying tread rubber. In the reverse situation, of having only the harder, more wear resistant rubber comprising all of the contact surface ( 134   b  only over 100% of contact surface  146 ) there is the potential of increased sliding due to the low grip levels, which can result in significant increase of temperatures and further mechanical degradation (softening) of the tread features that can ultimately result in inferior handling and slower lap times. The inventors have determined that this exemplary embodiment can provide a more improved tread feature configuration that is especially less sensitive to non-ideal camber curves that allows tire  100  to roll into a positive camber in a turn where tire  100  experiences relatively high cornering forces. The tread features of this exemplary embodiment are more optimized to provide and maintain the best level of grip while minimizing wear that occurs with severe cornering, 
         [0036]    Referring now to  FIG. 6 , this interior tread feature  134  provides another exemplary embodiment of a tread feature  134  that may be used for either first interior tread feature  134 , second interior tread feature  136 , or both. This exemplary embodiment is similar to  FIG. 5  except, as shown, the amount  146   a  of the interior contact surface  146  formed by first layer  134   a  is less for this embodiment than for the embodiment shown in  FIG. 5 . As compared to a tire having the wider interior contact surface like  146   a  of  FIG. 5 , this tire would be more advantageous for a vehicle with even poorer camber control. In other words, this embodiment can provide more wear resistant rubber along the tread feature&#39;s outer edge for protection on the exterior tires in hard cornering. Hard cornering places the outside edges of tread features (especially outside the tire center line) under much more severe situations for cornering stresses and wear. The inventors have determined that this embodiment can provide improved tread features that are less sensitive to non-ideal camber control in a turn where tire  100  experiences relatively high cornering forces. The tread features are more optimized to provide and maintain the best level of grip while minimizing wear that occurs with severe cornering in this situation by increasing the portion of  134   b  (harder wear resistant compound) relative to the  134   a  portion (shorter softer, high-grip compound) on  146 , the interior contact surface. 
         [0037]    A third exemplary embodiment of an interior tread feature that can be used for either or both of tread features  134  and  136  is shown in  FIG. 7 . Here, interior tread feature  134  is constructed from a first layer  134   a  that includes a first rubber composition and a second layer  134   b  that includes a second rubber composition. First layer  134   a  is wholly supported by second layer  134   b  and is formed as a skim on second layer  134   b.  This exemplary embodiment is similar to the previous embodiment of  FIGS. 5 and 6 , except that for the embodiment of  FIG. 7  first layer  134  forms all of the interior contact surface  146  for the unworn condition shown. As compared to a tire with both  134   a  and  134   b  forming the interior contact surface  146 , a tire with embodiment of  FIG. 7  can provide a larger area of high-grip tread material in the favorable situations. Examples applications include: 1) vehicles with excellent levels of camber control keeping the tread features parallel or nearly parallel with road surface for the majority of maneuvers (uniform or nearly uniform distribution of stresses across the tread band); 2) or, if the tread feature is interior of the tire&#39;s centerline away from the most severe cornering stresses and wear (exterior); 3) or if the feature is of low tread depth and is not as exposed to the high-shear and significant tread wear due to the improved stiffness of low tread depth features (UHP/DOT legal race tires with hallow tread depth often fall into this group. The embodiment of  FIG. 7  is useful in all these situations where wear is less of an issue and the softer, higher-grip tread rubber can remain intact with a lower wear rate to provide significant grip for longer durations. Likewise, the embodiment of  FIG. 7  is also preferred over the embodiment of a tread feature composed of only the softer high-grip rubber because without the support of the larger volume and higher modulus of  134   b,  the softer  134   a  layer still tends to wear at a significantly increase rate (two-to-three times the embodiment of  FIG. 7 ) due to the overall deformation of the tread feature and the resulting shear at the road-and-tread feature interface. 
         [0038]    Referring back to  FIG. 2 , as previously indicated, tread  102  includes a third interior tread feature  106  having a third interior contact surface  150 . For the exemplary embodiment shown in  FIG. 2 , third interior tread feature  106  includes a first layer  138   a  formed from a first rubber composition and having a relatively uniform thickness T along axial direction A. In addition, first layer  138   a  forms all of third interior contact surface  150  when tire  100  is in an unworn condition. As with previous embodiments, first layer  138   a  is wholly supported by first layer  138   b,  which is constructed from a second rubber composition. 
         [0039]      FIG. 8  provides another exemplary embodiment of third interior tread feature  138 . This exemplary embodiment is similar to the exemplary embodiment depicted in  FIG. 2  except that in  FIG. 8  first layer  138   a  forms only a portion  150   a  of the third interior contact surface  150 . For this exemplary embodiment, second layer  138   b  also forms a portion  150   b  of third interior contact surface  150 . Additionally, as shown in the radial cross-section view of  FIG. 8 , the profile of first layer  138   a  has a bottom  160  that forms an angle α with respect to third interior contact surface  150 . Similar to previous tread feature embodiments, angle α may be, for example, in the range of about 10 degrees to about 30 degrees. However, unlike previous embodiments, first layer  138   a  has a thickness T that decreases along the axially inward direction AI—i.e. in a direction moving from the outboard side  102  towards the inboard side  104  of tire  100 . Although bottom  160  is shown as linear, its profile could also be accurate as well. As compared to the embodiment for tread feature  138  shown in  FIG. 1 , the inventor have determined that the tread feature  138  shown in  FIG. 8  can provide improved cornering grip and wear resistance for the situation where the inside of the tire is subjected to the most severe stresses and loading. This situation typically occurs only on the interior tire on the inside cornering position on a vehicle with less than ideal camber control. It should be noted that the embodiments for the third interior tread feature shown in  FIGS. 1 ,  2 ,  3 , and  8  are appropriate for an interior tread feature that is positioned inboard of the centerline C/L of tire  100 . 
         [0040]    As stated above, for each exemplary tread feature, the first layer is constructed from a first rubber composition while the second layer is construction from a second rubber composition. In one exemplary aspect of the present invention, the first rubber composition has an MA10 at 23° C. of about 3.5 to about 5 while the second rubber composition has an MA10 at 23° C. of about 6 MPa or greater. In still another exemplary aspect of the present invention, the first rubber composition has a Shore A hardness of about 50 to about 65 while the second rubber composition has Shore A hardness of about 70 or greater. As used herein, Shore A hardness is measured according to ASTM D2240 (1997). 
         [0041]    It should be understood that the same first rubber composition may be used in each of the first layers of tread features  132 ,  134 ,  136 ,  138 , and/or  140  as described above. Alternatively, the composition of the first layer of each such tread feature may vary from tread feature to tread feature provided that a rubber composition having an elastic modulus and/or Shore Hardness relative to the second layer as described above is employed. For example, a first rubber composition may be used for the first layer of one tread feature while a third rubber composition is used for the first layer of another tread feature and the first layer of each such tread feature may be supported by a second layer constructed from a second rubber composition. 
         [0042]    As stated previously, the thickness of the first layer may vary. In one exemplary embodiment, the thickness T along radial direction R of the first layer is about 2.5 mm or less. Where the thickness varies with angle a as set forth above, a maximum thickness T along radial direction R of about 2.5 mm or less may be used in certain exemplary embodiments. In still other embodiments, the maximum thickness T of the first layer is in the range of about 0.5 mm to about 2.5 mm. In still other embodiments, where the tread has a thickness at centerline C/L that is below about 6.5 mm, the maximum thickness T could be in the range of about 2.5 mm to about 4 mm. 
         [0043]    Returning to  FIG. 2 , inboard tread feature  140  is shown without a first layer of tread rubber in this exemplary embodiment. However, in other exemplary embodiments of the invention, inboard tread feature could be constructed with a profiled first layer of tread rubber in a manner similar to that used e.g., for the third interior tread feature  138 . As such, inboard tread feature  140  could be constructed with a first layer forming all or part of the contact surface and having a constant thickness along the radial direction or having a thickness that tapers along the axially inward direction AI. Other configurations may be used as well. 
         [0044]      FIG. 3  provides another exemplary embodiment of a tread portion  106  of the present invention. This embodiment is similar to the exemplary embodiment of  FIG. 1  with certain exceptions. For instance, second interior tread feature  136  has a smaller portion of the first layer forming third interior contact surface  148  in a manner similar to the construction shown in  FIG. 6 . In addition, third interior tread feature  138  has a profiled first layer than tapers along the axially inward direction so that only a portion of the contact surface is formed by the first layer in a manner similar to the construction shown in  FIG. 8 . As compared to the exemplary embodiment of  FIG. 2 , the exemplary tread portion  106  of  FIG. 3  has shown improved grip and resistance to wear for the tire on the inside of a cornering vehicle where the inboard shoulder ( 104 ) becomes exposed to the highest cornering stresses and wear. In this situation (inside wheel in a corner), the inboard shoulder ( 104 ) and inner half of the tread ( 152 ,  150 ,  148 ) are carrying the highest, or all the normal and cornering force loads. The exterior side ( 102 ) of the tire may not even be in contact with the road surface due to weight transfer and insufficient camber control to keep the whole tread band or even part of the interior portion of the inner cornering tire in contact with the road surface. In this situation, the tread skim of the tread portion  106  in the orientation of  FIG. 8  (or,  FIG. 3  for all tread portions) provides the best grip and resistance to track wear for the tire on the interior position of the cornering vehicle. 
         [0045]    While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.