Patent Publication Number: US-9834035-B2

Title: Aerodynamically efficient spoke design for a vehicle wheel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present U.S. Continuation-in-Part application claims priority to U.S. Utility patent application Ser. No. 14/212,914 entitled “Aerodynamically Efficient Spoke Design for A Vehicle Wheel” filed on Mar. 14, 2014, which claims priority to U.S. Provisional Patent Application Ser. No. 61/793,605, filed on Mar. 15, 2013, and entitled “Aerodynamically Efficient Wheel Spoke Design”, the disclosure of which is hereby incorporated by reference as though set forth fully herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to a wheel design that provides improved aerodynamic performance. More specifically, the present disclosure relates to (a) a design of a wheel spoke that yields minimal power usage from the pumping of air during rotation to provide improved aerodynamics and (b) a design of a wheel spoke that optimizes the air pressure gradients under and around the vehicle affecting overall vehicle coefficient of drag. 
     BACKGROUND OF THE INVENTION 
     With recent efforts directed toward energy conservation along with the continuing escalation of fuel prices, the automotive industry has put an emphasis on increasing the fuel economy of vehicles that are put onto the road. Efforts to improve the fuel economy of vehicles have resided in improving the operation and efficiency of their engines, reducing the weight of their bodies and chassis, and improving the aerodynamic characteristics of their bodies. While great strides have been made in enhancing vehicle fuel economy as a result of improvements in these areas, there is still significant room for further advancement. 
     Currently, the impact of the wheels and their effect on vehicle aerodynamics as well as fuel economy has been largely unappreciated. While there have been efforts to design and manufacture lighter weight wheels, such as through the removal of material from the spokes or the backsides of the wheel, the primary goal of these efforts has generally been cost considerations and not aerodynamics or fuel economy. Indeed, the prior efforts to remove material from the back side of the wheel spokes likely negatively affected the wheel aerodynamics. 
     More recently, the potential aerodynamic impact of vehicle wheels themselves has been considered and has focused on the size and shape of the wheel turbine openings. These considerations have largely ignored the fact that most wheel assemblies today employ covers or other structures over the wheel outboard surface that are designed to enhance the aesthetics of the wheel. Any aerodynamic benefit that may result from the design of the wheel alone is not maximized when a wheel cover or other aesthetic feature is secured to the outboard surface of the wheel that does not take into account the aerodynamics of the overall wheel assembly. 
     It would thus be desirable to provide a wheel that overcomes the disadvantages associated with current wheels and helps contribute to improved fuel efficiency of a vehicle. 
     SUMMARY OF THE INVENTION 
     It is therefore an aspect of the present disclosure to provide a wheel for a vehicle that provides improved aerodynamics. 
     It is a related aspect of the present disclosure to provide a wheel assembly for a vehicle that provides improved aerodynamics. 
     It is a further aspect of the present disclosure to provide a wheel that yields improved fuel economy for a vehicle. 
     It is another related aspect of the present disclosure to provide a wheel assembly that yields improved fuel efficiency for a vehicle. 
     According to these and other aspects of the disclosure, a wheel for a vehicle is provided. The wheel includes an inner hub portion configured to receive a vehicle axle therethrough and defining an axis of rotation at a center thereof. The wheel also includes an outer rim portion, and a plurality of wheel spoke portions extending generally between the inner hub portion and the outer rim portion. The inner hub portion, the outer rim portions, and the plurality of wheel spoke portions cooperate to form a wheel outer surface having a plurality of turbine openings. Each of the plurality of wheel spoke portions has an outboard side adjacent the wheel outer surface, an inboard side opposite the spoke outboard side, a leading side surface extending generally in a direction between the inner hub portion and the outer rim portion and between the outboard side and the inboard side, and a trailing side surface extending generally in a direction between the inner hub portion and the outer rim portion and extending between the outboard side and the inboard side. A plurality of clad spokes each overly one of the wheel spoke portions. The clad spokes each include an outboard surface overlying the outboard side of the wheel spoke portion, a leading side surface overlying the leading side surface of the wheel spoke portion, and a trailing side surface overlying the trailing side surface of the wheel spoke portion. At least a segment of one of the leading side and trailing side surfaces of each of the clad spokes has a non-planar shape. 
     According to a further aspect of the disclosure, a wheel for a vehicle is provided. The wheel includes an inner hub portion configured to receive a vehicle axle therethrough and defining an axis of rotation at a center thereof. The wheel also includes an outer rim portion, and a plurality of wheel spoke portions extending generally between the inner hub portion and the outer rim portion. The inner hub portion, the outer rim portions, and the plurality of wheel spoke portions cooperate to form a wheel outer surface having a plurality of turbine openings. Each of the plurality of wheel spoke portions has an outboard side adjacent the wheel outer surface, an inboard side opposite the spoke outboard side, a leading side surface extending generally in a direction between the inner hub portion and the outer rim portion and between the outboard side and the inboard side, and a trailing side surface extending generally in a direction between the inner hub portion and the outer rim portion and extending between the outboard side and the inboard side. A plurality of clad spokes each overly at least a segment of one of the wheel spoke portions. A foam adhesive is disposed between each of the wheel spoke and the overlying clad spoke. The foam adhesive overlies the inboard surface of each of the wheel spokes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other aspects of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of an exemplary wheel; 
         FIG. 2  is a front view of an exemplary wheel; 
         FIG. 3  is a back view of an exemplary wheel; 
         FIG. 4  is an exploded view of an exemplary wheel assembly; 
         FIG. 5  is schematic cross-sectional illustration of a configuration of a wheel spoke in accordance with the prior art; 
         FIG. 6  is a schematic cross-sectional illustration of a wheel spoke for a wheel assembly in accordance with an aspect of the present disclosure; 
         FIG. 7  is a schematic cross-sectional illustration of a wheel spoke for a wheel assembly in accordance with another aspect of the present disclosure; 
         FIG. 8  is a schematic cross-sectional illustration of a wheel spoke design in accordance with still another aspect of the present disclosure; 
         FIG. 9  is a schematic cross-sectional illustration of a wheel spoke design for a wheel assembly in accordance with yet another aspect of the present disclosure; 
         FIG. 10  is a schematic cross-sectional illustration of a wheel spoke design for a wheel assembly in accordance with a further aspect of the present disclosure; 
         FIG. 11  is a schematic cross-sectional illustration of a wheel spoke design for a wheel assembly in accordance with yet another aspect of the present disclosure; 
         FIG. 12  is a schematic cross-sectional illustration of a wheel spoke design for a wheel assembly in accordance with yet a further aspect of the present disclosure; 
         FIG. 13  is a schematic cross-sectional illustration of a wheel spoke design for a wheel assembly in accordance with still another aspect of the present disclosure; 
         FIG. 14  is a schematic cross-sectional illustration a wheel spoke design in accordance with still yet a further aspect of the present disclosure; 
         FIG. 15  is a schematic cross-sectional illustration of a wheel spoke design in accordance with still another aspect of the present disclosure; 
         FIG. 16  is a schematic cross-sectional illustration of a wheel spoke design in accordance with yet a further aspect of the present disclosure; and 
         FIG. 17  is a schematic cross-sectional illustration of a wheel spoke design in accordance with yet another aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of description herein, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the disclosure as oriented in the FIGs and are intended merely for purposes of illustration and are not intended to be limiting. It is to be understood that the disclosure may assume various alternative orientations and features, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. The specific dimensions and other physical characteristics relating to the aspects disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     The present disclosure relates generally to a wheel and a wheel assembly for an automobile that can provide reduced power usage as well as improved vehicle aerodynamics and fuel economy. The amount of fuel economy savings can vary based upon other factors, including the configuration of the vehicle and whether the savings may be measured based on city or highway driving. According to an aspect, assuming the same vehicle, the disclosed wheel and wheel assembly can provide benefits over conventional wheels and wheel assemblies. The disclosed wheel and wheel assembly are intended for use with an automotive vehicle, such as a car or truck. In accordance with another aspect, the wheel and wheel assembly could alternatively be used in connection with other types of vehicles. 
       FIGS. 1 through 3  generally illustrate a wheel  100  in accordance with an aspect of the disclosure. According to an aspect, the wheel  100  has an inboard side  102  and an outboard side  104  and includes an inner hub portion  106  having an opening  108  for receipt of an axle (not shown) therethrough. The center of the opening  108  defines an axis of rotation. The hub portion  106  also includes a plurality of lug openings  110  formed therein which receive lug bolts (not shown), for securing the wheel  100  for rotation with a vehicle axle. The wheel  100  also includes a peripheral rim portion  112  with an outer peripheral flange surface  114 . The wheel  100  additionally includes a plurality of wheel spokes  116  extending generally radially between the outer peripheral flange surface  114  and the inner hub portion  106 . The outer peripheral flange surface  114 , the inner hub portion  106 , and the plurality of spokes  116  together define a plurality of wheel turbine openings  120 . The wheel turbine openings  120  are generally defined by an inner boundary or footprint. The spokes and turbine openings may have a variety of different sizes, shapes and geometries and may be defined by a variety of different surfaces. Additionally, the wheel may employ any number of spokes. 
     As shown, the wheel turbine opening perimeter  130  may be generally defined by inner side surfaces  122 ,  124  of adjacent spokes  116  and an inner periphery  132  of the outer peripheral flange surface  114 . The wheel turbine openings  120  can have a variety of different shapes and sizes, including non-uniform shapes. Additionally, any number of turbine openings  120  can be formed in the wheel surface  110 . According to an aspect, the wheel  100  can be formed from any suitable material, such as aluminum or steel, as is conventional in the automotive industry. Other materials may alternatively be employed. Additionally, any conventional forming or manufacturing process may be employed. 
       FIG. 4  generally illustrates a wheel assembly  10  in accordance with an aspect of the disclosure. Pursuant to an aspect, the wheel assembly  10  includes a wheel  100  and a wheel cover or clad  200  designed to overlie the outboard side  104  of the wheel such as for aesthetic purposes. The wheel clad  200  can be permanently secured to the wheel  100  by a suitable adhesive to form a completed wheel assembly  10 . According to an aspect, the wheel clad  200  may be secured to the wheel  100  by foam adhesive, as generally designated by reference number  300 . According to another aspect, any other suitable adhesive may be employed. For example, a silicon adhesive, such as a one part or two part RTV adhesive, may be employed. 
     As generally shown, the wheel clad  200  has an inboard surface  202  and an outboard surface  204 . The wheel clad  200  has a clad outer peripheral portion  206  that is intended to axially align with or overlie at least a portion of the wheel outer peripheral flange surface  114 . The wheel clad  200  also includes a hub portion  208  that can be axially aligned with at least a portion of the wheel inner opening portion  106 . The wheel clad  200  also can include a plurality of clad spokes  210  that extend radially between the clad outer peripheral portion  206  and the clad inner opening portion  208 . The clad spokes  210  may at least partially align with and overlap the wheel spokes  116 . The clad outer peripheral portion  206 , the clad inner opening portion  208 , and the clad spokes  210  cooperate to define a plurality of clad turbine openings  214 . The clad  200  also can include a plurality of lug bolt receiving holes  212  formed therein for receiving lugs. It will be appreciated that the clad turbine openings  214  according to the present disclosure can have a variety of different sizes and shapes and can be located in different places on the clad  200 . 
     The wheel clad  200  may be permanently secured to the wheel  100  such that the clad inboard surface  202  faces the wheel outboard side  104 . The plurality of clad turbine openings  214  can each have a clad turbine opening perimeter  216  that may be defined by opposing side surfaces  218  of adjacent clad spokes  210  and an inner periphery  220  of the clad outer rim portion  206 . As shown, the opposing side surfaces  218  may extend downward toward the wheel outboard surface  104  in a generally planar fashion. The plurality of clad turbine openings  214  may be generally axially aligned with the wheel turbine openings  120 , such that each clad turbine opening perimeter  216  may be disposed entirely within a respective one of the wheel turbine openings  120 . 
     According to a further aspect, the wheel clad  200  may be constructed of plastic or composite material. However, other suitable materials may be employed as may be preferred or dictated by the design constraints of the particular application. According to another aspect, the wheel clad  200  may have a metal plated outer surface, such as a chrome plated surface, to provide desirable aesthetics and to yield an appearance that the clad is an integral part of the wheel. Numerous structural combinations of wheel dads with chrome-plated outboard surfaces have attracted great interest from vehicle manufacturers, because they are lightweight, aesthetically pleasing and offer designers complete flexibility with regard to the aesthetic effect that can be created for a specific vehicle regardless of whether these vehicles use steel or aluminum wheels. The clad  200  may be formed by suitable injection molding processes. 
     Known efforts to reduce the weight of conventional wheels and wheel assemblies has involved removing weight from the inboard side of the wheel. One such exemplary weight removal structure is as a weight reduction pocket which is formed on the inner surface  134  of the wheel spokes  116 . Exemplary weight reduction pockets  136  formed on the inner surface  134  of the wheel spoke  116  are generally illustrated in  FIG. 3 . 
     A weight reduction pocket  136  is also illustrated in  FIG. 5 , which schematically illustrates a conventional wheel spoke design for a wheel assembly. As shown in  FIG. 5 , the wheel spoke  116  may be a generally cast metal structure that has a generally uniform cross-section. The wheel spoke  116  has an inner surface  134 , an outer surface  138  and a pair of spoke inner side surfaces  122 ,  124 , which extend between the inner surface  134  and the outer surface  138 . As shown, a clad spoke  210  can overlie the wheel spoke  116  and encapsulates it on three sides. An adhesive, generally designated by reference number  300 , can fill the area between the inboard surface  202  of the clad spoke  210  and the outboard side  104  of the wheel spoke  116 . The inner surface  134  of the wheel spoke  116  may be machined and have a weight reduction pocket  136  formed therein through the removal of material. As shown, the weight reduction pocket  136  can be formed as a depression or recess generally in the middle portion of the inner surface  134  of the wheel spoke  116 . While this feature serves to lighten the wheel, it negatively impact aerodynamics of the inboard side  104  of the wheel  100 . 
     According to an aspect of the present disclosure, the aerodynamics of the wheel may be improved by altering the shape of the back, rear or inboard side of the wheel spoke. More specifically, according to an aspect, the inboard side of the wheel spoke can be formed to create an efficient surface that does not pump air, in the same fashion as a propeller or fan would. According to another aspect, the inboard side of the wheel can be formed to minimize the power used to rotate the wheel through the air or can be formed to create an effect that provides a pressure differential between the inboard side and the outboard side of the wheel, allowing the evacuation of high pressure air from underneath the vehicle, thereby reducing the overall drag coefficient of the wheel and vehicle. According to another aspect, the orientation of each of the spokes may be changed to provide an aerodynamic benefit, as discussed above. 
       FIG. 6  illustrates one exemplary design for a wheel assembly that yields improved aerodynamics. As shown,  FIG. 6  is a cross-section of a portion of wheel assembly  600  according to an aspect of the present disclosure, which yields improved aerodynamics through altering the configuration of the inboard side of the wheel. As shown, the wheel assembly  600  can include a wheel  602  and a wheel clad  604  and the basic components of the wheel and wheel clad may be configured as discussed above. The differences may reside in the configuration of the wheel spoke and the clad spoke. 
     According to an aspect, the wheel spoke  606  has an inboard surface  608 , an outboard surface  610 , a leading surface  612  extending between the inboard surface  608  and the outboard surface  610 , and a trailing surface  614  extending between the inboard surface  608  and the outboard surface  610 . According to another aspect, the inboard surface  608  may be configured as a generally convex shape such that it is generally arcuate in a direction from the leading surface  612  to the trailing surface  614  with a generally middle portion  616  of the inboard surface  608  is bowed away from the outboard surface  610  of the spoke  606 . Put another way, the generally middle portion  616  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  610  of the spoke  606 . An inner edge  618  of the leading surface  612  may be disposed a distance (D le ) from the reference plane (P). An inner edge  620  of the trailing surface  614  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, the distance (D m ) may be greater than each of distance (D le ) and distance (D te ). According to another aspect, distance (D le ) may be equal to distance (D te ). However, distances (D le ) and (D te ) do not need to be equal. 
     According to an aspect, the outboard surface  610  of the wheel spoke  606  can include a weight reduction pocket  622 , which can serve to decrease the amount of material that is required to form the wheel spoke thus making the wheel spoke lighter and less expensive. The weight reduction pocket  622  may be sized and shaped in order to maximize the removal of material without compromising the strength or structural integrity of the wheel spoke. The weight reduction pocket may obviously take on a variety of different shapes. Alternatively, instead of a weight reduction pocket, other weight reducing or relief structures may be employed. According to an aspect, the inboard surface of the wheel spoke may be left as-cast. Alternatively, the inboard surface of the spoke could include machining to achieve brake clearance tolerances. Additionally, by placing the weight reduction pocket on the outboard surface  610  of the spoke  606 , the inboard side of the spoke can be shaped to have increased aerodynamic effect. According to a still further aspect, the spoke  606  could be rotated either clockwise or counterclockwise (as viewed in  FIG. 6 ) about its center such that the inboard surface  608  is angled either downwardly or upwardly with respect to the clad leading surface  634 . 
     According to another aspect, a clad spoke  630  can overlie the wheel spoke  606 . The clad spoke  630  can include an outboard surface  632 , a leading side surface  634 , and a trailing side surface  636 . According to a further aspect, the leading side surface  634  has an outer edge  638  and an inner edge  640 . The trailing side surface  636  also has an outer edge  642  and an inner edge  644 . As shown, the inner edge  638  of the leading side surface  634  of the clad spoke  630  may be spaced a first distance (d 1 ) from the inner edge  618  of the leading surface  618  of the wheel spoke  606 . As also shown, the inner edge  644  of the trailing side surface  636  of the clad spoke  630  may be spaced a second distance (d 2 ) from the inner edge  620  of the trailing surface  612  of the wheel spoke  606 . According to an aspect, the first distance (d 1 ) may be greater than the second distance (d 2 ). According to another aspect, the first distance (d 1 ) may be substantially greater than the second distance (d 2 ). According to a further aspect, the leading surface  618  of the wheel spoke  606  may be oriented substantially parallel to the leading side surface  634 . As also shown, the trailing surface  614  of the wheel spoke  606  may be oriented such that it is not parallel to the trailing side surface  636 . Put another way, the leading side surface  634  can be disposed at an angle (α) with respect to the outboard surface  632  which angle may be less than an angle (θ) as measured between the trailing side surface  636  and the outboard surface  632 . 
     According to another aspect, foam adhesive  650  may be utilized to fill an area between the wheel spoke  606  and the clad spoke  630 . According to another aspect, foam adhesive can be utilized to assist in forming at least a portion of an inboard surface  608  of the wheel spoke  606 . As shown, a first foam portion  652  can extend between the inner edge  640  of the leading side surface  634  of the clad surface  630  and the inner edge  618  of the leading surface  612  of the wheel spoke  606 . According to an aspect, the first foam portion  652  may be disposed flush to the edges  618 ,  640  and configured to match a contour of the inboard surface  608  of the wheel spoke  606 . As also shown, a second foam portion  654  can extend between the inner edge  644  of the trailing side surface  636  of the clad spoke  630  and the inner edge  620  of the trailing surface  614  of the wheel spoke  606 . According to another aspect, the second foam portion  654  may be disposed flush to those edges  620 ,  644  and also configured to match a contour of the inboard surface  608  of the wheel spoke  606 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A spoke inboard surface  608  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 7  illustrates another exemplary design for a wheel assembly that yields improved vehicle aerodynamics through altering the configuration of the rear side of the wheel spoke. As shown,  FIG. 7  is a cross-section of a portion of a wheel assembly  700  according to an aspect of the present disclosure. The wheel assembly  700  can include a wheel  702  and a wheel clad  704 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences may reside in the configuration of the wheel spoke and the clad spoke. 
     According to an aspect, the wheel  702  includes the wheel spoke  706  having an inboard surface  708 , an outboard surface  710 , and a leading surface  712  extending between the inboard surface  708  and the outboard surface  710 , and a trailing surface  714  extending between the inboard surface  708  and the outboard surface  710 . According to another aspect, the inboard surface  708  may be configured as a generally concave shape such that it is generally arcuate in a direction from the leading surface  712  to the trailing surface  714  where a generally middle portion  716  of the inboard surface  708  is bowed toward from the outboard surface  710  of the spoke  706 . Put another way, the generally middle portion  716  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  710  of the spoke  706 . An inner edge  718  of the leading surface  712  can be disposed a distance (D le ) from the reference plane (P). An inner edge  720  of the trailing surface  714  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, the distance (D m ) may be greater than the distance (D le ) and less than the distance (D te ). However, the relative distances can vary. By this configuration, the leading surface  712  may be shorter than the trailing surface  714 . According to an aspect, the outboard surface  710  of the wheel spoke  706  as defined by the reference plane may be oriented at an angle with respect to the wheel outer surface. According to a further aspect, the wheel spoke  706  could be rotated (either clockwise or counter-clockwise) about a center point so that one of the leading surface  712  or the trailing surface  714  is lower with respect to the Plane (P) than the other. By this configuration, the length of these surfaces  712 ,  714  could be equal L 1 =L 2 . 
     According to another aspect, a clad spoke  730  can overlie the wheel spoke  706 . The clad spoke  730  can include an outboard surface  732 , a leading side surface  734 , and a trailing side surface  736 . According to a further aspect, the leading side surface  734  has an outer edge  738  and an inner edge  740 . The trailing side surface  736  also has an outer edge  742  and an inner edge  744 . According to this aspect, the inner edge  738  of the leading side surface  734  of the clad spoke  730  may be spaced apart generally the same distance as the distance between the inner edge  744  of the trailing side surface  736  of the clad spoke  730  and the inner edge  720  of the trailing surface  712  of the wheel spoke  706 . According to an aspect, the leading side surface  734  of the clad spoke  730  may have a shorter length (L l ) than the length (L t ) of the trailing side surface  736 . This configuration can yield a pitch in the wheel spoke that creates a pressure differential between outboard pressure zone (Po) and the inboard pressure zone (Pi). Again, the pitch of the spoke could be created through rotation of the spoke about its center. 
     According to another aspect, foam adhesive  750  may be utilized to fill an area between the wheel spoke  706  and the clad spoke  730 . According to another aspect, foam adhesive can be utilized to assist in forming an inboard surface  708  of the wheel spoke  706 . As shown, a first foam portion  752  can extend between the inner edge  740  of the leading side surface  734  of the clad surface  730  and the inner edge  718  of the leading surface  712  of the wheel spoke  706 . According to an aspect, the first foam portion  752  may be disposed flush to the edges  718 ,  740  are configured to match a contour of the inboard surface  708  of the wheel spoke  706 . As also shown, a second foam portion  754  can extend between the inner edge  744  of the trailing side surface  736  of the clad spoke  730  and the inner edge  720  of the trailing surface  714  of the wheel spoke  706 . According to another aspect, the second foam portion  754  may be disposed flush to those edges  720 ,  744  and also configured to match a contour of the inboard surface  708  of the wheel spoke  706 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A spoke inboard surface  708  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 8  illustrates an exemplary design for a wheel that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 8  is a cross-section of a portion of wheel  802  according to an aspect of the present disclosure. The basic components of the wheel may be configured, as discussed above. The differences may reside in the configuration of the wheel spoke. As shown, the wheel spoke  806  of  FIG. 8  has the same configuration as the wheel spoke of  FIG. 7 . However, with respect to  FIG. 8 , there is no wheel clad disposed overtop of the wheel surface. The outboard surface  810  of the wheel spoke and thus the wheel is exposed. According to an aspect, the outboard surface of the wheel, including the wheel spoke geometry, are configured to provide the aerodynamic benefits. 
       FIG. 9  illustrates still another exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 9  is a cross-section of a portion of wheel assembly  900  according to an aspect of the present disclosure. The wheel assembly  900  can include a wheel  902  and a wheel clad  904 . The basic components of the wheel and wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and clad spoke. 
     According to an aspect, the wheel spoke  906  has an inboard surface  908 , an outboard surface  910 , and a leading surface  912  extending between the inboard surface  908  and the outboard surface  910 , and a trailing surface  914  extending between the inboard surface  908  and the outboard surface  910 . According to another aspect, the inboard surface  908  can be configured as a generally convex shape such that it is generally arcuate in a direction from the leading surface  912  to the trailing surface  914  with a generally middle portion  916  of the inboard surface  908  that is bowed away from the outboard surface  910  of the spoke  906 . Put another way, the generally middle portion  916  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  910  of the spoke  906 . According to another aspect, the middle portion  916  can be configured with at least a generally planar section for manufacturing purposes without altering the overall convex shape of the inboard surface  908 . An inner edge  918  of the leading surface  912  may be disposed a distance (D le ) from the reference plane (P). An inner edge  920  of the trailing surface  914  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, distance (D m ) may be greater than each of distance (D le ) and distance (D te ). According to another aspect, distance (D le ) may be equal to distance (D te ). However, distances (D le ) and (D te ) do not need to be equal. 
     According to another aspect, a clad spoke  930  can overlie the wheel spoke  906 . The clad spoke  930  can include an outboard surface  932 , a leading side surface  934 , and a trailing side surface  936 . According to a further aspect, the leading side surface  934  has an outer edge  938  and an inner edge  940 . The trailing side surface  936  also has an outer edge  942  and an inner edge  944 . As shown, the inner edge  938  of the leading side surface  934  of the clad spoke  930  may be spaced a first distance (d 1 ) from the inner edge  918  of the leading surface  918  of the wheel spoke  906 . As also shown, the inner edge  944  of the trailing side surface  936  of the clad spoke  930  may be spaced a second distance (d 2 ) from the inner edge  920  of the trailing surface  912  of the wheel spoke  906 . According to an aspect, the first distance (d 1 ) and the second distance (d 2 ) may be generally equal. According to a further aspect, the leading surface  918  of the wheel spoke  906  may be oriented substantially parallel to the leading side surface  934  of the wheel spoke. As also shown, the trailing surface  914  of the wheel spoke  906  may also be oriented substantially parallel to the trailing side surface  936  of the clad spoke. 
     According to another aspect, foam adhesive  950  may be utilized to fill an area between the wheel spoke  906  and the clad spoke  930 . According to another aspect, foam adhesive can be utilized to assist in forming an inboard surface  908  of the wheel spoke  906 . As shown, a first foam portion  952  may extend between the inner edge  940  of the leading side surface  934  of the clad surface  930  and the inner edge  918  of the leading surface  912  of the wheel spoke  906 . According to an aspect, the first foam portion  952  can be disposed flush to the edges  918 ,  940  and configured to match a contour of the inboard surface  908  of the wheel spoke  906 . As also shown, a second foam portion  954  can extend between the inner edge  944  of the trailing side surface  936  of the clad spoke  930  and the inner edge  920  of the trailing surface  914  of the wheel spoke  906 . According to another aspect, the second foam portion  954  may be disposed flush to those edges  920 ,  944  and also configured to match a contour of the inboard surface  908  of the wheel spoke  906 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A wheel spoke having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. According to an aspect, the surface shape of the inboard surface, the outboard surface, and the side surfaces can create a shape for efficient ventilation drag by reducing the pumping effect. 
       FIG. 10  illustrates still a further exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 10  is a cross-section of a portion of a wheel assembly  1000  according to an aspect of the present disclosure. The wheel assembly  1000  can include a wheel  1002  and a wheel clad  1004 . The basic components of the wheel and wheel clad may be configured, as discussed above. The differences can reside in the configuration of the wheel and clad spoke. 
     According to an aspect, the wheel spoke  1006  has an inboard surface  1008 , an outboard surface  1010 , and a leading surface  1012  extending between the inboard surface  1008  and the outboard surface  1010 , and a trailing surface  1014  extending between the inboard surface  1008  and the outboard surface  1010 . According to another aspect, the inboard surface  1008  is configured with a generally convex shape such that it is generally arcuate in a direction from the leading surface  1012  to the trailing surface  1014  where a generally middle portion  1016  of the inboard surface  1008  is bowed away from the outboard surface  1010  of the spoke  1006 . Put another way, the generally middle portion  1016  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  1010  of the spoke  1006 . According to another aspect, the middle portion  1016  can be configured with at least a generally planar portion for manufacturing purposes without altering the overall convex shape of the inboard surface  1008 . An inner edge  1018  of the leading surface  1012  may be disposed a distance (D le ) from the reference plane (P). An inner edge  1020  of the trailing surface  1014  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, distance (D m ) can be greater than each of distance (D le ) and distance (D te ). According to another aspect, distance (D le ) may be equal to distance (D te ). However, distances (D le ) and (D te ) do not need to be equal. Again, as discussed above, the spokes could be rotated about its center to change its pitch. 
     According to an aspect, the outboard surface  1010  of the wheel spoke  1006  can include a pair of weight reduction structures  1022 , which can serve to decrease the amount of material that is required to form the wheel spoke. As shown, the weight reduction structures  1022  may be formed in the leading surface  1012  and the trailing surface  1014 . The weight reduction structures  1022  may be sized and shaped in order to maximize the removal of material without compromising the strength or structural integrity of the wheel spoke. The weight reduction structures  1022  may obviously take on a variety of different shapes. Alternatively, other weight reducing or relief structures may be employed. Additionally, by placing the weight reduction structures on the outboard side and side surfaces of the spoke, the inboard side of the spoke can be shaped to have increased aerodynamic effect. 
     According to another aspect, a clad spoke  1030  can overlie the wheel spoke  1006 . The clad spoke  1030  can include an outboard surface  1032 , a leading side surface  1034 , and a trailing side surface  1036 . According to a further aspect, the leading side surface  1034  has an outer edge  1038  and an inner edge  1040 . The trailing side surface  1036  also has an outer edge  1042  and an inner edge  1044 . As shown, the inner edge  1038  of the leading side surface  1034  of the clad spoke  1030  may be spaced a first distance (d 1 ) from the inner edge  1018  of the leading surface  1012  of the wheel spoke  1006 . As also shown, the inner edge  1044  of the trailing side surface  1036  of the clad spoke  1030  may be spaced a second distance (d 2 ) from the inner edge  1020  of the trailing surface  1014  of the wheel spoke  1006 . According to an aspect, the first distance (d 1 ) and the second distance (d 2 ) may be generally equal. According to a further aspect, the first distance (d 1 ) and the second distance (d 2 ) may be very small such that there is little space between the inner edges  1018 ,  1020  of the wheel spoke  1006  and the inner edges  1040 ,  1044  of the clad spoke  1030 . By this configuration, the inboard surface  1008  of the wheel spoke  1006  may be almost entirely responsible for the spoke shape. According to an aspect, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     According to another aspect, foam adhesive  1050  may be utilized to fill an area between the wheel spoke  1006  and the clad spoke  1030 . 
     A wheel spoke having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. According to an aspect, the surface shape of the inboard surface, the outboard surface, and the side surfaces can create a shape for efficient ventilation drag by reducing the pumping effect. 
       FIG. 11  illustrates one exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 11  is a cross-section of a portion of a wheel assembly  1100  according to an aspect of the present disclosure. The wheel assembly  1100  includes a wheel  1102  and a wheel clad  1104 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and clad spoke. 
     According to an aspect, the wheel  1102  includes the wheel spoke  1106  having an inboard surface  1108 , an outboard surface  1110 , and a leading surface  1112  extending between the inboard surface  1108  and the outboard surface  1110 , and a trailing surface  1114  extending between the inboard surface  1108  and the outboard surface  1110 . According to another aspect, the inboard surface  1108  may be configured as a generally concave shape such that it is generally arcuate in a direction from the leading surface  1112  to the trailing surface  1114  where a generally middle portion  1116  of the inboard surface  1108  is bowed toward from the outboard surface  1110  of the spoke  1106 . Put another way, the generally middle portion  1116  may be disposed a distance (D m ) away from a reference plane P defined by the outboard surface  1110  of the spoke  1106 . An inner edge  1118  of the leading surface  1112  may be disposed a distance (D le ) from the reference plane (P). An inner edge  1120  of the trailing surface  1114  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, distance (D m ) may be greater than distance (D le ) and less than distance (D te ). However, the relative distances can vary. By this configuration, the leading surface  1112  may be shorter than the trailing surface  1114 . According to an aspect, the outboard surface  1110  of the wheel spoke  1106  as defined by the reference plane (P) may be oriented at an angle with respect to the wheel outer surface, as shown. According to a further aspect, the wheel spoke  1106  could be rotated (either clockwise or counter-clockwise) about a center point so that one of the leading surface  1112  or the trailing surface  1114  is lower with respect to the Plane (P) than the other. By this configuration, the length of these surfaces  1112 ,  1114  could be equal L 1 =L 2 . 
     According to an aspect, the outboard surface  1100  of the wheel spoke  1106  can include a pair of weight reduction structures  1122 , which can serve to decrease the amount of material that is required to form the wheel spoke. As shown, the weight reduction structures may be formed in the leading surface  1112  and the trailing surface  1114 . The weight reduction structures  1122  may be sized and shaped in order to maximize the removal of material without compromising the strength or structural integrity of the wheel spoke. The weight reduction structures  1122  may obviously take on a variety of different shapes. Alternatively, other weight reducing or relief structures may be employed. Additionally, by placing the weight reduction structures on the outboard side and side surfaces of the spoke, the inboard side of the spoke can be shaped to have increased aerodynamic effect. 
     According to another aspect, a clad spoke  1130  can overlie the wheel spoke  1106 . The clad spoke  1130  can include an outboard surface  1132 , a leading side surface  1134 , and a trailing side surface  1136 . According to a further aspect, the leading side surface  1134  has an outer edge  1138  and an inner edge  1140 . The trailing side surface  1136  also has an outer edge  1142  and an inner edge  1144 . According to this aspect, the inner edge  1138  of the leading side surface  1134  of the clad spoke  1130  may be spaced apart generally the same distances as the distance between the inner edge  1144  of the trailing side surface  1136  of the clad spoke  1130  and the inner edge  1120  of the trailing surface  1112  of the wheel spoke  1106 . According to an aspect, the leading side surface  1134  of the clad spoke  1130  may have a shorter length (L l ) than the length (L t ) of the trailing side surface  1136 . This configuration can yield a pitch in the wheel spoke that creates a pressure differential between outboard pressure zone (Po) and the inboard pressure zone (Pi). As first distance (d 1 ) between the inner edge  1118  of the wheel spoke leading surface  1112  and the inner edge  1138  of the clad spoke leading side surface  1134  may be very small. Similarly, a second distance (d 2 ) between the inner edge  1144  of the clad spoke trailing side surface  1134  and the inner edge  1120  of the wheel spoke trailing surface  1112  is also very small. By this configuration, the inboard surface  1108  of the wheel spoke  1106  may be almost entirely responsible for the shape if the inner side of the spoke. According to a further aspect, the wheel spoke  1106  could be rotated (either clockwise or counter-clockwise) about a center point so that one of the leading surface  1112  or the trailing surface  1114  is lower with respect to the Plane (P) than the other. By this configuration, the length of these surfaces  1112 ,  1114  could be equal L 1 =L 2 . 
     According to another aspect, foam adhesive  1150  may be utilized to fill an area between the wheel spoke  1106  and the clad spoke  1130 . A spoke inboard surface  1108  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 12  illustrates one exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 12  is a cross-section of a portion of a wheel assembly  1200  according to an aspect of the present disclosure. The wheel assembly  1200  includes a wheel  1202  and a wheel clad  1204 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and the clad spoke. 
     According to an aspect, the wheel spoke  1206  has an inboard surface  1208 , an outboard surface  1210 , and a leading surface  1212  extending between the inboard surface  1208  and the outboard surface  1210 , and a trailing surface  1214  extending between the inboard surface  1208  and the outboard surface  1210 . According to another aspect, the inboard surface  1208  can be configured as a generally convex shape such that it is generally arcuate in a direction from the leading surface  1212  to the trailing surface  1214  with a generally middle portion  1216  of the inboard surface  1208  being bowed away from the outboard surface  1210  of the spoke  1206 . Put another way, the generally middle portion  1216  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  1210  of the spoke  1206 . An inner edge  1218  of the leading surface  1212  may be disposed a distance (D le ) from the reference plane (P). An inner edge  1220  of the trailing surface  1214  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, distance (D m ) may be greater than each of distance (D le ) and distance (D te ). According to another aspect, distance (D le ) may be equal to distance (D te ). However, distances (D le ) and (D te ) do not need to be equal. According to a further aspect, the wheel spoke  1206  could be rotated (either clockwise or counter-clockwise) about a center point so that one of the leading surface  1212  or the trailing surface  1214  is lower with respect to the Plane (P) than the other. By this configuration, the length of these surfaces  1212 ,  1214  could be equal L 1 =L 2 . 
     According to another aspect, a clad spoke  1230  can overlie the wheel spoke  1206 . According to an aspect, the clad spoke  1230  may be generally egg-shaped. As shown, the clad spoke  1230  can include an outboard surface  1232 , a leading side surface  1234 , and a trailing side surface  1236 . According to a further aspect, the leading side surface  1234  has an outer edge  1238  and an inner edge  1240 . The trailing side surface  1236  also has an outer edge  1242  and an inner edge  1244 . As shown, the leading side surface  1234  and the trailing side surface  1234  may terminate at their inner edges  1240 ,  1244  adjacent the outboard surface  1232  of the wheel spoke  1206 . Additionally, the shapes and degrees of curvature of the leading side surface  1234  and the trailing side surface  1236  may vary. As shown, the leading side surface  1234  may extend inwardly with respect to the clad spoke outboard surface  1232  such that its downturn (as viewed in the FIG) is relatively sharp. According to an aspect, this can generally match the orientation of the wheel spoke leading surface  1212 . As also shown, the trailing side surface  1236  may extend inwardly with respect to the clad spoke outboard surface  1232  such that its downturn (as viewed in the FIG) is more gradual. According to an aspect, this can generally match the orientation of the wheel spoke trailing edge  1214 . 
     According to another aspect, foam adhesive  1250  may be utilized to fill an area between the wheel spoke  1206  and the clad spoke  1230 . According to another aspect, foam adhesive can be utilized to assist in forming an inboard surface  1208  of the wheel spoke  1206 . As shown, a first foam portion  1252  may extend between the inner edge  1240  of the leading side surface  1234  of the clad surface  1230  and the inner edge  1218  of the leading surface  1212  of the wheel spoke  1206 . According to an aspect, the first foam portion  1252  can be disposed flush to the edges  1218 ,  1240  and configured to match a contour of the inboard surface  1208  of the wheel spoke  1206 . As also shown, a second foam portion  1254  can extend between the inner edge  1244  of the trailing side surface  1236  of the clad spoke  1230  and the inner edge  1220  of the trailing surface  1214  of the wheel spoke  1206 . According to another aspect, the second foam portion  1254  may be disposed flush to those edges  1220 ,  1244  and also configured to match a contour of the inboard surface  1208  of the wheel spoke  1206 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A wheel spoke having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. According to an aspect, the surface shape of the inboard surface, the outboard surface, and the side surfaces can create a shape for efficient ventilation drag by reducing the pumping effect. 
       FIG. 13  illustrates one exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 13  is a cross-section of a portion of a wheel assembly  1300  according to an aspect of the present disclosure. The wheel assembly  1300  can include a wheel  1302  and a wheel clad  1304 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and the clad spoke. 
     According to an aspect, the wheel  1302  includes the wheel spoke  1306  having an inboard surface  1308 , an outboard surface  1310 , and a leading surface  1312  extending between the inboard surface  1308  and the outboard surface  1310 , and a trailing surface  1314  extending between the inboard surface  1308  and the outboard surface  1310 . According to another aspect, the inboard surface  1308  may be configured as a generally convex shape such that it is generally arcuate in a direction from the leading surface  1312  to the trailing surface  1314  where a generally middle portion  1316  of the inboard surface  1308  is bowed toward the outboard surface  1310  of the spoke  1306 . The outboard surface  1310  may have a similar shape. Put another way, the generally middle portion  1316  may be disposed a distance (D m ) away from a reference plane (P) defined by the outboard surface  1310  of the spoke  1306 . An inner edge  1318  of the leading surface  1312  may be disposed a distance (D le ) from the reference plane (P). An inner edge  1320  of the trailing surface  1314  may be disposed a distance (D te ) from the reference plane (P). According to an aspect, the distance (D m ) may be greater than the distance (D le ) and less than the distance (D te ). However, the relative distances can vary. By this configuration, the leading surface  1312  may be shorter than the trailing surface  1314 . According to an aspect, the outboard surface  1310  of the wheel spoke  1306  as defined by the reference plane may be oriented at an angle with respect to the wheel outer surface. According to a further aspect, the wheel spoke  1306  could be rotated (either clockwise or counter-clockwise) about a center point so that one of the leading surface  1312  or the trailing surface  1314  is lower with respect to the Plane (P) than the other. By this configuration, the length of these surfaces  1312 ,  1314  could be equal L 1 =L 2 . 
     According to another aspect, a clad spoke  1330  can overlie the wheel spoke  1306 . The clad spoke  1330  can include an outboard surface  1332 , a leading side surface  1334 , and a trailing side surface  1336 . According to a further aspect, the leading side surface  1334  has an outer edge  1338  and an inner edge  1340 . The trailing side surface  1336  also has an outer edge  1342  and an inner edge  1344 . According to this aspect, the inner edge  1338  of the leading side surface  1334  of the clad spoke  1330  may be spaced apart generally the same distances as the distance between the inner edge  1344  of the trailing side surface  1336  of the clad spoke  1330  and the inner edge  1320  of the trailing surface  1312  of the wheel spoke  1306 . According to an aspect, the leading side surface  1334  of the clad spoke  1330  may have a shorter length (L l ) than the length (L t ) of the trailing side surface  1336 . This configuration can yield a pitch in the wheel spoke that creates a pressure differential between outboard pressure zone (Po) and the inboard pressure zone (Pi). 
     According to another aspect, foam adhesive  1350  may be utilized to fill an area between the wheel spoke  1306  and the clad spoke  1330 . According to another aspect, foam adhesive can be utilized to assist in forming an inboard surface  1308  of the wheel spoke  1306 . As shown, a first foam portion  1352  may extend between the inner edge  1340  of the leading side surface  1334  of the clad surface  1330  and the inner edge  1318  of the leading surface  1312  of the wheel spoke  1306 . According to an aspect, the first foam portion  1352  may be disposed flush to the edges  1318 ,  1340  and configured to match a contour of the inboard surface  1308  of the wheel spoke  1306 . As also shown, a second foam portion  1354  can extend between the inner edge  1344  of the trailing side surface  1336  of the clad spoke  1330  and the inner edge  1320  of the trailing surface  1314  of the wheel spoke  1306 . According to another aspect, the second foam portion  1354  may be disposed flush to those edges  1320 ,  1344  and also configured to match a contour of the inboard surface  1308  of the wheel spoke  1306 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A spoke inboard surface  1308  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 14  illustrates an exemplary design for a wheel that yields improved aerodynamics through altering the configuration of the inboard side of the wheel spoke. As shown,  FIG. 14  is a cross-section of a portion of wheel  1302  according to an aspect of the present disclosure. The basic components of the wheel may be configured, as discussed above. The differences may reside in the configuration of the wheel spoke. As shown, the wheel spoke  1306  of  FIG. 14  has the same configuration as the wheel spoke of  FIG. 13 . However, with respect to  FIG. 14 , there is no wheel clad disposed overtop of the wheel surface. According to an aspect, the outboard surface  1410  of the wheel spoke and thus the wheel is exposed. The outboard surface of the wheel, including the wheel spoke geometry are configured to provide the aerodynamic benefits. 
       FIG. 15  illustrates another exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the leading edge and trailing edge of the wheel clad. As shown,  FIG. 15  is a cross-section of a portion of a wheel assembly  1500  according to an aspect of the present disclosure. The wheel assembly  1500  can include a wheel  1502  and a wheel clad  1504 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and the clad spoke. 
     According to an aspect, the wheel  1502  includes a wheel spoke  1506  having an inboard surface  1508 , an outboard surface  1510 , a leading surface  1512  extending between the inboard surface  1508  and the outboard surface  1510 , and a trailing surface  1514  extending between the inboard surface  1508  and the outboard surface  1510 . According to another aspect, the inboard surface  1508  and the outboard surface  1510  may each be generally planar and parallel to one another. Similarly, the wheel leading surface  1512  and the wheel trailing surface  1514  may be configured as generally planar surfaces that are parallel to one another. However, the surfaces could each have a variety of different configurations. For example, the wheel spoke surfaces can match the configuration of the clad spoke surfaces, as discussed below. According to a further aspect, the wheel spoke  1506  can include one or more pockets  1520  formed in its interior. For example, the wheel spoke  1506  may be formed by a hollow core casting process such that the pockets  1520  are formed in the spoke interiors such that they spokes are generally hollow. As will be appreciated, interior spoke pockets can decrease the weight of the wheel without affecting its structural integrity, which can provide a lighter wheel assembly resulting in improved fuel economy for a vehicle as well as other aerodynamic benefits. It will be appreciated that hollow pockets in the spokes can be formed in a variety of different ways by a variety of different processes. It will further be appreciated that the pockets  1520  can have a variety of different configurations. 
     According to another aspect, a clad spoke  1530  can overlie the wheel spoke  1506 . The clad spoke  1530  can include an outboard surface  1532 , a leading side surface  1534 , and a trailing side surface  1536 . According to a further aspect, the leading side surface  1534  has an outer edge  1538  adjacent the outboard surface  1532  and an inner edge  1540  opposite the outer edge  1538 . The trailing side surface  1536  also has an outer edge  1542  adjacent the outboard surface  1532  and an inner edge  1544  opposite the outer edge  1538 . According to this aspect, the leading side surface  1534  may be configured as a generally concave shape such that it is generally arcuate in a direction from the outer edge  1538  to the inner edge  1540  where a generally middle portion  1546  of the leading side surface  1534  is bowed inwardly. The trailing side surface  1536  may have a similar shape. According to a still further aspect, the trailing side surface  1536  may have a different shape than the leading side surface  1534 . Further, the trailing and leading side surfaces  1536 ,  1534  may have other non-planar shapes. 
     According to another aspect, foam adhesive  1550  may be utilized to fill an area between the wheel spoke  1506  and the clad spoke  1530 . According to another aspect, foam adhesive can be utilized to assist in forming the inboard surface  1508  of the wheel spoke  1506 . As shown, a first foam portion  1552  may extend between the inner edge  1540  of the leading side surface  1534  of the clad surface  1530  and an inner edge  1516  of the leading surface  1512  of the wheel spoke  1506 . According to an aspect, the first foam portion  1552  may be disposed flush to the edges  1518 ,  1540  and configured to match a contour of the inboard surface  1508  of the wheel spoke  1506 . As also shown, a second foam portion  1554  can extend between the inner edge  1544  of the trailing side surface  1536  of the clad spoke  1530  and an inner edge  1518  of the trailing surface  1514  of the wheel spoke  1506 . According to another aspect, the second foam portion  1554  may be disposed flush to those edges  1520 ,  1544  and also configured to match a contour of the inboard surface  1508  of the wheel spoke  1506 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A spoke leading side surface  1534  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 16  illustrates another exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the leading edge and trailing edge of the wheel clad. As shown,  FIG. 16  is a cross-section of a portion of a wheel assembly  1600  according to an aspect of the present disclosure. The wheel assembly  1600  can include a wheel  1602  and a wheel clad  1604 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and the clad spoke. 
     According to an aspect, the wheel  1602  includes a wheel spoke  1606  having an inboard surface  1608 , an outboard surface  1610 , a leading surface  1612  extending between the inboard surface  1608  and the outboard surface  1610 , and a trailing surface  1614  extending between the inboard surface  1608  and the outboard surface  1610 . According to another aspect, the inboard surface  1608  and the outboard surface  1610  may each be generally planar and parallel to one another. Similarly, the wheel leading surface  1612  and the wheel trailing surface  1614  may be configured as generally planar surfaces that are parallel to one another. However, the surfaces could each have a variety of different configurations. For example, the wheel spoke surfaces can match the configuration of the clad spoke surfaces, as discussed below. According to a further aspect, the wheel spoke  1606  can include one or more pockets  1620  formed in its interior. For example, the wheel spoke  1606  may be formed by a hollow core casting process such that the pockets  1620  are formed in the spoke interiors such that they spokes are generally hollow. As will be appreciated, interior spoke pockets can decrease the weight of the wheel without affecting its structural integrity, which can provide a lighter wheel assembly resulting in improved fuel economy for a vehicle as well as other aerodynamic benefits. It will be appreciated that hollow pockets in the spokes can be formed in a variety of different ways by a variety of different processes. It will further be appreciated that the pockets  1620  can have a variety of different configurations. 
     According to another aspect, a clad spoke  1630  can overlie the wheel spoke  1606 . The clad spoke  1630  can include an outboard surface  1632 , a leading side surface  1634 , and a trailing side surface  1636 . According to a further aspect, the leading side surface  1634  has an outer edge  1638  adjacent the outboard surface  1632  and an inner edge  1640  opposite the outer edge  1638 . The trailing side surface  1636  also has an outer edge  1642  adjacent the outboard surface  1632  and an inner edge  1644  opposite the outer edge  1638 . According to this aspect, the leading side surface  1634  may be configured as a generally convex shape such that it is generally arcuate in a direction from the outer edge  1638  to the inner edge  1640  where a generally middle portion  1646  of the leading side surface  1634  is bowed outwardly. The trailing side surface  1636  may have a similar shape. According to a still further aspect, the trailing side surface  1636  may have a different shape than the leading side surface  1634 . Further, the trailing and leading side surfaces  1636 ,  1634  may have other non-planar shapes. 
     According to another aspect, foam adhesive  1650  may be utilized to fill an area between the wheel spoke  1606  and the clad spoke  1630 . According to another aspect, foam adhesive  1650  can be utilized to assist in forming the inboard surface  1608  of the wheel spoke  1606 . As shown, a first foam portion  1652  may extend between the inner edge  1640  of the leading side surface  1634  of the clad surface  1630  and an inner edge  1616  of the leading surface  1612  of the wheel spoke  1606 . According to an aspect, the first foam portion  1652  may be disposed flush to the edges  1618 ,  1640  and configured to match a contour of the inboard surface  1608  of the wheel spoke  1606 . As also shown, a second foam portion  1654  can extend between the inner edge  1644  of the trailing side surface  1636  of the clad spoke  1630  and an inner edge  1618  of the trailing surface  1614  of the wheel spoke  1606 . According to another aspect, the second foam portion  1654  may be disposed flush to those edges  1620 ,  1644  and also configured to match a contour of the inboard surface  1608  of the wheel spoke  1606 . In other words, the foam exposed on the back side of the wheel can be shaped to provide an aero-efficient surface as the front-side to rear-side surface geometry is achieved. 
     A spoke leading side surface  1634  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
       FIG. 17  illustrates another exemplary design for a wheel assembly that yields improved aerodynamics through altering the configuration of the inboard side and outboard side of the wheel clad. As shown,  FIG. 17  is a cross-section of a portion of a wheel assembly  1700  according to an aspect of the present disclosure. The wheel assembly  1700  can include a wheel  1702  and a wheel clad  1704 . The basic components of the wheel and the wheel clad may be configured as discussed above. The differences can reside in the configuration of the wheel and the clad spoke. 
     According to an aspect, the wheel  1702  includes a wheel spoke  1706  having an inboard surface  1708 , an outboard surface  1710 , a leading surface  1712  extending between the inboard surface  1708  and the outboard surface  1710 , and a trailing surface  1714  extending between the inboard surface  1708  and the outboard surface  1710 . According to another aspect, the inboard surface  1708  and the outboard surface  1710  may each be generally planar and parallel to one another. Similarly, the wheel leading surface  1712  and the wheel trailing surface  1714  may be configured as generally planar surfaces that are parallel to one another. However, the surfaces could each have a variety of different configurations. According to a further aspect, the wheel spoke  1706  can include one or more pockets  1720  formed in its interior. For example, the wheel spoke  1706  may be formed by a hollow core casting process such that the pockets  1720  are formed in the spoke interiors such that they spokes are generally hollow. As will be appreciated, interior spoke pockets can decrease the weight of the wheel without affecting its structural integrity, which can provide a lighter wheel assembly resulting in improved fuel economy for a vehicle as well as other aerodynamic benefits. It will be appreciated that hollow pockets in the spokes can be formed in a variety of different ways by a variety of different processes. It will further be appreciated that the pockets  1720  can have a variety of different configurations. 
     According to another aspect, a clad spoke  1730  can overlie the wheel spoke  1706 . The clad spoke  1730  can include an outboard surface  1732 , a leading side surface  1734 , and a trailing side surface  1736 . According to a further aspect, the leading side surface  1734  has an outer edge  1738  adjacent the outboard surface  1732  and an inner edge  1740  opposite the outer edge  1738 . The trailing side surface  1736  also has an outer edge  1742  adjacent the outboard surface  1732  and an inner edge  1744  opposite the outer edge  1738 . According to this aspect, the leading side surface  1734  and the trailing side surface  1736  may have a variety of different configurations. 
     According to another aspect, foam adhesive  1750  may be utilized to fill an area between the wheel spoke  1706  and the clad spoke  1730 . According to another aspect, foam adhesive can be utilized to assist in forming the inboard side of the wheel assembly  1700 . As shown, the inboard surface  1752  of the wheel  1708  may be recessed with respect to the inner edge  1740  of the leading side surface  1734  and the inner edge  1744  of the trailing side surface  1736 . According to this aspect, the foam adhesive  1750  may fully encapsulate the wheel spoke  1706  such that its forms the inboard side  1752  of the wheel assembly. According to another aspect, the adhesive foam  1750  may be disposed flush with the inner edge  1740  of the leading side surface  1734  and the inner edge  1744  of the trailing side surface  1736 . Utilization of the foam adhesive  1750  to form the inboard side of the wheel assembly  1700  allows the inboard side  1752  to be formed in a variety of shapes, including planar, curved, convex, and concave. A variety of other shapes may also be employed. 
     A wheel assembly  1700  having this configuration can provide an aero-efficient shape that results from the configuration of both the outboard surface and the inboard surface to reduce pumping losses. 
     Other variants could also be employed as well as any combination of features from the aspects above. As will be appreciated according to the disclosure wheel and the cladding collectively can provide aero-efficient surface geometry on the front and the back side of the wheel. According to an aspect, the shape of the spoke can be achieved by moving the parting line of a wheel mold, or forging die, to the center section of the spoke relative to the face and back surface of the spoke. The parting line left on the wheel spoke surface could be covered by a cladding or other decorative insert that would also provide a decorative and aero-efficient shape to the front side of the spoke. The efficient surface geometry transitions and the shape of the wheel backbone, enabled by the move of the mold or die parting line on the backbone wheel to a more center location on the spoke relative to the spoke face and rear surface, can be achieved on either the leading-edge, trailing edge, or on both edges of the spoke. 
     The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive. 
     Certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub combination. Further, reference to values stated in ranges includes each and every value within that range. 
     Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims. 
     The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover any and all such modifications, enhancements, and other embodiments that fall within the scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description. 
     Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the embodiments of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the embodiments of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.