Patent Publication Number: US-2017370430-A1

Title: Heat dissipating brake rotor

Description:
BACKGROUND 
     1. Field of the Disclosure 
     This application is generally related to disc brakes for at least partially human powered vehicles, and more particularly to a heat dissipating brake rotor for same. 
     2. Description of Related Art 
     Disc brakes are well known for use on two-wheeled vehicles. Some disc brakes are also known for use specifically on bicycles. The typical disc brake system has a disc shaped brake rotor with a braking portion or friction region extending around the brake track or brake body. The system also has a brake caliper with brake pads that, when the caliper is actuated, contact the braking portion or friction region of the brake rotor to slow the bicycle or vehicle. In some instances, heavy braking may be required to slow the vehicle or bicycle, such as during high-speed downhill descents. Problems sometimes arise during such heavy braking situations that may not otherwise occur under normal or light use conditions. 
     In heavy or extreme braking conditions, excessive heat may be generated in the brake rotor. The typical brake rotor is not designed to dissipate excessive heat. Thus, the brake rotor is typically only capable of minimal heat dissipation. Excessive heat in the brake rotor can result in thermal fade in the brake system during heavy or extreme braking, which can render the brakes significantly less responsive. Excessive heat also increases the heat load on the brake rotor, as well as on the caliper, pads, fluid, and component seals. 
     Further, the typical brake rotor is not designed to handle thermal expansion in the brake rotor resulting from extreme temperatures during such heavy braking conditions or resulting from intermittent extreme usage and extreme temperature fluctuations during extended use. The brake rotor may warp during use when subjected to excessive heat or may even suffer permanent deformation. Existing solutions have been devised to try and improve heat dissipation in brake rotors for two-wheeled vehicles. One such solution has been to add aluminum material to the braking portion or friction region of the brake rotor. However, when exposed to excessive heat, such brake rotors can melt. Also, these attempted solutions have resulted in significantly higher manufacturing and part costs. As a result, such solutions have not been suitable for most two-wheeled vehicle markets or consumers. 
     SUMMARY 
     In one example according to the teachings of the present disclosure, a brake rotor for a two-wheeled vehicle, such as bicycle, has a brake body formed of a first material. The brake body has a generally annular shape with a radially outer friction region and a radially inner heat dissipation region. The heat dissipation region has a first axial contact surface. The brake rotor also has a carrier with a coupling region. The carrier is configured for transmitting a braking load between the braking body and the coupling region. The carrier includes a cooling body formed of a second material. The cooling body is coupled to the first axial contact surface of the brake rotor. The second material has a higher thermal conductivity than the first material. The cooling body is in contact with the first axial contact surface around the brake body for a majority of a circumference of the heat dissipation region. 
     In one example, the second material can be different from the first material. 
     In one example, the cooling body can be in contact with the first axial contact surface around the brake body for between 300 degrees and 360 degrees of the circumference of the heat dissipation region. 
     In one example, the cooling body can be in contact with the first axial contact surface around the brake body for 360 degrees of the circumference of the heat dissipation region. 
     In one example, the second material can be aluminum or an aluminum alloy. 
     In one example, the first material can be a stainless steel. 
     In one example, the heat dissipation region of the brake body can define or be part of an attachment portion of the brake body or such an attachment portion can define or be a part of the heat dissipation region. 
     In one example, the carrier can be disposed at least partially within a central opening of the brake body. The carrier can have one or more first contact sections in contact with the first axial contact surface. The first contact sections can be in contact with the heat dissipation region of the brake body. 
     In one example, the cooling body can include a second cooling body. One or both of the cooling body and the second cooling body can be disposed at least partially within a central opening of the brake body. The cooling body can have one or more first contact sections in contact with the first axial contact surface. The second cooling body can have one or more second contact sections in contact with a second axial contact surface of the brake body or of the heat dissipation region of the brake body. The second axial contact surface can face opposite the first axial contact surface on the brake body. The brake body or the heat dissipation region of the brake body can be captured or disposed between the one or more first contact sections and the one or more second contact sections. 
     In one example, the cooling body can include a second cooling body. One or more second contact sections of the second cooling body, one or more first contact sections of the first cooling body, or a combination thereof, can be configured and arranged to contact a second axial contact surface opposite the first axial contact surface on the brake body, the first axial contact surface, or both, for 360 degrees around the circumference of the heat dissipation region. 
     In one example, the braking load can result from a braking force applied to the friction region. 
     In one example, the coupling region of the carrier can be configured for mounting to a hub of a wheel of the bicycle. 
     In one example, at least a portion of the cooling body of the carrier can radially overlap the heat dissipation region of the brake body. 
     In one example according to the teachings of the present disclosure, a brake rotor for a two-wheeled vehicle, such as a bicycle, has a brake body formed of a first material. The brake body has a generally annular shape with a first axial surface and a second axial surface opposite the first axial surface. The brake rotor has a carrier formed of a second material. The carrier is coupled to the brake body such that one or more first contact sections of a first cooling body of the carrier contact the first axial surface of the brake body. The brake rotor has a second cooling body formed of a third material. The second cooling body is coupled to the brake body such that one or more second contact sections of the second cooling body contact the second axial surface of the brake body. At least one of the second material or the third material has a higher heat conductivity than the first material of the brake body. 
     In one example, the first material can be a stainless steel. 
     In one example, the second material and the third material can be different from one another. 
     In one example, either one of or both of the second and the third material can be different from the first material. 
     In one example, the third material can be substantially the same as the second material. 
     In one example, the second material can be aluminum or an aluminum alloy. 
     In one example, the second and third materials can both be aluminum or an aluminum alloy. 
     In one example, the brake body can further include a central opening, an outer periphery, an inner periphery facing radially inward around the central opening, an attachment portion or heat dissipation region adjacent the inner periphery, and a braking portion or friction region disposed radially outward of the attachment portion. 
     In one example, the brake rotor can include an attachment portion radially inward of a braking portion. The attachment portion can have a first thickness between the first axial surface and the second axial surface and the braking portion can have a second thickness between the first axial surface and the second axial surface. The first thickness can be less than the second thickness. 
     In one example, the brake rotor can include an attachment portion radially inward of a braking portion. A second axial braking surface of the braking portion and a second axial contact surface of the attachment portion on the second axial surface can be co-planar with one another. A first axial braking surface of the braking portion and a first axial contact surface of the attachment portion on the first axial surface can lie in different planes, i.e., not be co-planar with one another. 
     In one example, the cooling body or the second cooling body can reside in an axial recess in the first axial surface or the second axial surface of the brake body. 
     In one example, the one or more first contact sections of the carrier can contact an attachment portion on the first axial surface of the brake body. The one or more second contact sections of the second cooling body can contact the attachment portion on the second axial surface of the brake body. 
     In one example, the cooling body and second cooling body can contact one another in a mating region that is radially inward of an inner periphery of the brake body. 
     In on example, the carrier and second cooling body can be joined to one another and to the brake body via fasteners through an attachment portion of the brake body, the second cooling body, and the carrier. 
     In one example, the one or more second contact sections and the one or more first contact sections can be substantially flat with the second cooling body and the carrier fastened to one another and to the brake body. However, the one or more second contact sections, the one or more first contact sections, or both may not be flat before the second cooling body and carrier are joined to one another and to the brake body. 
     In one example, the second cooling body can have a non-flat annular shape that is rendered substantially flat when the second cooling body and carrier are joined to one another and to the brake body. 
     In one example, the brake body can have a plurality of attachment features formed into an inner periphery of the brake body. An attachment portion of the brake body can be disposed or captured between the one or more second contact sections and the one or more first contact sections. The second cooling body and the carrier can be joined to one another and to the brake body by fasteners through the plurality of attachment features. The plurality of attachment features can be configured to permit relative radial expansion between the brake body and the second cooling body and carrier. 
     In one example, the brake rotor can be specifically constructed for a bicycle. 
     In one example, the one or more second contact sections, the one or more first contact sections, or both can contact the brake body 360 degrees around the brake body. 
     In one example according to the teachings of the present disclosure, a brake rotor for a two-wheeled vehicle, such as a bicycle, has a brake body formed of a first material. The brake body has a generally annular shape, a first axial surface, a second axial surface opposite the first axial surface, and an inner periphery that faces radially inward and extends circumferentially around the brake body. The brake rotor has a carrier formed of a second material that has a higher thermal conductivity than the first material. The carrier is coupled to the brake body with a portion of the carrier in contact with the first axial surface. The brake rotor also has a second cooling body. The second cooling body is coupled to the brake body with a portion of the second cooling body in contact with the second axial surface. The brake body is disposed between the portion of the second cooling body and the portion of the carrier. A plurality of attachment features are formed into the inner periphery of the brake body in a radial extending direction. The second cooling body and carrier are joined to one another and to the brake body by fasteners through the plurality of attachment features. The plurality of attachment features are configured to permit relative radial expansion between the brake body and the second cooling body and carrier. 
     In one example, the second cooling body can have a non-flat, wavy, or non-planar shape. 
     In one example, the second cooling body can have a non-flat or nonplanar configuration that can become substantially planar when the second cooling body and the carrier are joined with the fasteners. 
     In one example, the second cooling body can be annular or ring shaped. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which: 
         FIG. 1  shows a side elevational view of one example of a bicycle, which may be fitted with one or more brake rotors constructed in accordance with the teachings of this disclosure. 
         FIG. 2  shows a front or first side perspective view of one example of a brake rotor constructed in accordance with the teachings of the present disclosure and which can be used on the bicycle of  FIG. 1 . 
         FIG. 3  shows a front or first side plan view of the brake rotor of  FIG. 2 . 
         FIG. 4  shows a rear or second side plan view of the brake rotor of  FIG. 2 . 
         FIG. 5  shows an end or edge view of the brake rotor of  FIG. 2 . 
         FIG. 6  shows a front or first side perspective exploded view of the brake rotor of  FIG. 2 . 
         FIG. 7  shows a front or first side plan view of one example of a brake body part of the brake rotor of  FIG. 2 . 
         FIG. 8A  shows an enlarged segment of portions of the brake body taken from circle  8 A in  FIG. 7 . 
         FIG. 8B  shows a cross-section of the portions of the brake body taken along line  8 B- 8 B in  FIG. 8A . 
         FIG. 9  shows a front or first side plan view of another example of a brake body part that can be used on the brake rotor of  FIG. 2 . 
         FIG. 10  shows a front or first side plan view of another example of a brake body part that can be used on the brake rotor of  FIG. 2 . 
         FIG. 11  shows a front or first side plan view of one example of a carrier part of the brake rotor of  FIG. 2 . 
         FIG. 12A  shows a cross-section of portions of the carrier taken along line  12 A- 12 A in  FIG. 11 . 
         FIG. 12B  shows a cross-section of portions of the carrier taken along line  12 B- 12 B in  FIG. 11 . 
         FIG. 13  shows a front or first side plan view of one example of a second cooling body part of the brake rotor of  FIG. 2 . 
         FIG. 14  shows an end or edge view of the second cooling body of  FIG. 12 . 
         FIG. 15A  shows a cross-section of the brake rotor taken along line  15 A- 15 A in  FIG. 3 . 
         FIG. 15B  shows an enlarged segment of the brake rotor cross-section taken from circle  15 B in  FIG. 15A . 
         FIG. 15C  shows a cross-section of the brake rotor taken along line  15 C- 15 C in  FIG. 3 . 
         FIG. 16  shows a front or first side plan view of another example of a second cooling body part that can be used on the brake rotor or  FIG. 2 . 
         FIG. 17A  shows an end or edge view of the second cooling body of  FIG. 16 . 
         FIG. 17B  shows an enlarged portion of the second cooling body taken from circle  17 B in  FIG. 17A . 
         FIG. 18  shows a brake rotor with an alternate wheel coupling portion. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The brake rotors disclosed and described herein solve or improve upon one or more of the above-noted and/or other problems and disadvantages with prior known brake rotor deigns. The disclosed brake rotors can dissipate heat in the brake rotor to the surrounding environment during use. The disclosed brake rotors can aid in lowering the temperature of the brake rotor during use. The disclosed brake rotors, as a result, can reduce or eliminate thermal fade during heavy or extreme braking conditions. The disclosed brake rotors can also assist in reducing heat load on the brake rotor, the brake caliper, the brake pads, the brake fluid, and the component fluid seals. The disclosed brake rotors can withstand and allow for heat expansion in order to reduce or eliminate warping or permanent deformation in the brake rotor. The disclosed brake rotors can be fabricated and assembled using conventional manufacturing and assembly processes, including standard rivets, standard machining, and other standard operations. Thus, the disclosed brake rotors can be less expensive than other attempted heat dissipating rotor solutions. The disclosed brake rotors can be fabricated whereby the brake body portion is made entirely of stainless steel to withstand higher braking power and brake rotor temperatures. 
     Thus, brake rotors with heat dissipating characteristics are disclosed herein. The disclosed brake rotors can include a brake body and a heat sink or cooling element coupled to the brake body. In one example, the cooling element can be formed of a cooling body, which can be formed of a material having a higher thermal conductivity than the brake body material. In one example, the cooling body can be attached to or be an integral portion of a carrier that is coupled to the brake body. In one example, the cooling element or cooling body can include a second cooling body coupled to the brake body. In one example, the cooling element or cooling body can contact the brake body over a majority of the circumference of an attachment portion or heat dissipation region of the brake body. In one example, the cooling element can include both a cooling body, which is part of the carrier, and a second cooling body coupled to the brake body. One or both of the cooling body and second cooling body may be formed of the material having a higher thermal conductivity than the brake body material. In one example, both the cooling body of the carrier and the second cooling body can be formed of materials that are different from and that have a higher thermal conductivity than the material of the brake body. In one example, the brake body can be disposed or captured between portions of the carrier and the second cooling body. In one example, the cooling element, or the cooling body and second cooling body can continuously contact the brake body between 300 and 360 degrees around the circumference of an attachment portion or heat dissipation region of the brake body. In one example, the cooling body and second cooling body can contact one another and can each contact the brake body. These and other objects, features, and advantages of the disclosed brake rotors will become apparent to those having ordinary skill in the art upon reading this disclosure. 
     Turning now to the drawings,  FIG. 1  illustrates one example of a two-wheeled vehicle on which the disclosed brake rotors may be implemented. In this example, the two-wheeled vehicle is one possible type of bicycle  20 , such as a mountain bicycle. The bicycle  20  has a frame  22 , handlebars  24  near a front end of the frame, and a seat  26  for supporting a rider over a top of the frame. The bicycle  20  also has a first or front wheel  28  supporting the front end of the frame  22  and a second or rear wheel  30  supporting a rear end of the frame. The bicycle  20  also has a drive train  32  with a crank assembly  34  that is operatively coupled via a chain  36  to a rear cassette (not shown) near a rotation axis of the rear wheel  30 . While the bicycle  20  depicted in  FIG. 1  is a mountain bicycle, the brake rotor embodiments and examples disclosed herein may be implemented on other types of bicycles such as, for example, road bicycles, as well as bicycles with mechanical (e.g., cable, hydraulic, pneumatic, etc.) and non-mechanical (e.g., wired, wireless) drive systems. The disclosed brake rotors may also be implemented on other types of two-wheeled vehicles as well. 
     With that in mind, the bicycle  20  of  FIG. 1  also has a hydraulic brake system  40 . In the illustrated embodiment, the hydraulic brake system  40  includes a first brake lever assembly  42  disposed on the handlebars  24  and a second brake lever assembly (not shown), also disposed on the handlebars. The first brake lever assembly  42  is hydraulically coupled to a first brake caliper  44  via a first hydraulic brake line  46 . On the bicycle  20  in this embodiment, the first brake caliper  44  is operatively coupled to the front wheel  28 . The second brake lever assembly is hydraulically coupled to a second brake caliper  48  via a second hydraulic brake line  50 . On the bicycle  20 , the second brake caliper  48  is operatively coupled to the rear wheel  30 . In other embodiments, the hydraulic brake system  40  may include one or more additional and/or alternative components and/or may be configured in other ways. Additionally, the hydraulic brake system  40  may be replaced by a different type of brake system, such as a non-hydraulic brake system using mechanical brake cables, wires, or the like or such as a non-mechanical brake system utilizing electronic or wireless components. 
     In this example, the bicycle  20  also has a first or front brake rotor  60  carried at the rotation axis A of the front wheel  28  for rotation therewith. The bicycle  20  also has a rear brake rotor  62  carried at the rotation axis of the rear wheel  30  for rotation therewith. Each of the front and rear brake rotors  60  and  62  can be constructed according to the teachings of the present disclosure, as described in more detail below. When the first brake lever assembly  42  is actuated, brake fluid flows within the first brake line  46  to the first brake caliper  44  and actuates brake pads carried by the first brake caliper. The pads, though not shown herein, are in contact with a portion of the first brake rotor  60 . Friction between the brake pads and the brake rotor  60  acts to slow rotation of and thus brake the front wheel  28 . Likewise, when the second brake lever assembly is actuated, brake fluid flows within the second brake lines  50  to the second brake caliper  48  and actuates brake pads carried by the second brake caliper. The pads are in contact with a portion of the second brake rotor  62  and friction between the brake pads and the brake rotor  62  acts to slow rotation of and thus brake the rear wheel  30 . 
     When the brake pads of the first brake caliper  44  contact and apply pressure against surfaces of the first brake rotor  60 , the friction generates heat. Likewise, when the pads of the second brake caliper  48  contact and apply pressure against surfaces of the second brake rotor  62 , the friction generates heat. The disclosed brake rotor embodiments are configured to effectively dissipate heat generated during such a braking operation, as described in more detail below. The first and second brake rotors  60 ,  62  may be of the exact same size on the bicycle  20  or the two brake rotors may be of a different size. It is possible that the brake rotors  60  and  62  also have the identical construction on the bicycle  20 . However, it is also possible that the two brake rotors  60 ,  62  have different constructions and/or that only one of the brake rotors, such as the front brake rotor  60 , is constructed according to the teachings of the present disclosure. In the description below, only the front brake rotor  60  is described in detail. However, the description may be equally applicable to the rear brake rotor as well, though not mentioned after this point herein. 
       FIG. 2  shows one example of the front brake rotor  60  constructed in accordance with the teachings of the present disclosure. In this example, the brake rotor  60  generally has a brake track or brake body, hereinafter referred to as the brake body  70 , and a cooling element or heat sink, hereinafter referred to as the heat sink  72 , coupled to the brake body. The brake body  70  can be formed of a first material. At least part of the heat sink  72  can be formed of a heat dissipating material that is different from and/or that has a higher thermal conductivity than the first material of the brake body  70 . The heat dissipating material that forms at least part of the heat sink  72  has a higher thermal conductivity than the first material of the brake body  70  to absorb or conduct heat from the brake body to the heat sink  72 , as discussed in more detail below. 
     Basic details of the front brake rotor  60  are described below with reference to  FIGS. 2-5 . As shown in  FIGS. 2 and 3 , the brake body  70  can be generally annular or have somewhat of a ring shape. The brake body  70  can have or define a radially outer friction region or braking portion, hereinafter referred to as the friction region  74 . A periphery  76  of the brake body  70  is defined by the outer radial edge of the friction region  74 . In one example, the brake rotor  60  has a carrier  78  that is coupled or connected to the brake body  70 . The carrier  78  is configured to join or mount the brake body  70  to a hub or other part of the front wheel  28  of the bicycle  20  for rotation with the front wheel. The carrier  78  in this example is disposed radially inward of the friction region  74  on the brake body  70 . Details of the carrier  78 , including a cooling body or a first cooling body of the heat sink  72 , are described below. 
     As shown in  FIGS. 4 and 5 , the brake rotor  60  in one example can also have a backing body or second cooling body, hereinafter referred to as the second cooling body  80 , coupled or connected to the brake body  70 . The second cooling body  80  is configured to assist in securing the carrier  78  to the brake body and forms part of the heat sink  72 . The second cooling body  80  is also disposed radially inward of the friction region  74  on the brake body  70 . The rotation axis A is depicted in  FIG. 5  and provides the reference herein for the use of the terms radial, radial direction, axial and axial direction. 
     In one example, the second cooling body  80  can be formed of the heat dissipating material and may define the entire heat sink  72 . In another example, the carrier  78  or a cooling body thereof can be formed of the heat dissipating material and may define the entire heat sink  72 . In such examples, the other of the cooling body or carrier  78  or the second cooling body  80  can be formed of another material, i.e., a third material. The third material may be different from both the first material and the heat dissipating material or may be the same as the first material of the brake body  70 . In still another example, as disclosed herein, each of the carrier  78  or a cooling body thereof and the second cooling body  80  can form a part of the heat sink  72 . In such an example, the carrier  78  or the cooling body can be formed of a second material and the second cooling body  80  can be formed of a third material. Both of the second and third materials can then be heat dissipating materials, i.e., with a higher thermal conductivity than the first material of the brake body  70 . In one example, the second and third materials can be substantially similar to one another. In other words, the second and third materials would then each have at least similar thermal conductivity characteristics and a thermal conductivity that is higher than that of the first material of the brake body  70 . In still another example, as in the disclosed embodiment of  FIGS. 2-4 , each of the carrier  78  or a cooling body thereof and second cooling body  80  can form a part of the heat sink  72  and each of the second and third materials can be the same material. 
     In an embodiment, the third material may have a higher thermal conductivity than both the first material and the second material. For example, the first material may be a steel, such as a stainless steel, to allow for braking forces applied thereon, the second material may be aluminum or an aluminum alloy so as to have structural properties to transmit torque resulting from the braking forces yet have a higher thermal conductivity than the first steel material, and the third material may be a material such as copper or a copper alloy so as to provide the second cooling body  80  an even higher thermal conductivity than the carrier  78  (e.g. the first cooling body). Other high thermal conductivity materials may be used in the construction of the second cooling body  80  as well to provide high thermal conductivity, even relative to the first cooling body. For example, diamond based materials such as natural, isotopically enriched, and/or other manmade diamond materials, gold or gold alloys, silver or silver alloys, graphene, graphite, and/or combinations thereof may be used in the construction of the second cooling body to provide for the higher thermal conductivity. 
       FIG. 6  shows an exploded perspective view of the brake rotor  60  depicted in  FIGS. 2-5 , including the brake body  70 , the carrier  78 , and the second cooling body  80 . Details of the brake body  70  are first described with reference to  FIGS. 6, 7, 8A, and 8B . As shown in  FIGS. 6 and 7 , the brake body  70 , as noted above, is annular or generally ring shaped and includes the radially outer friction region  74 . The outer periphery of the brake body  70  is defined by the outermost radial edge of the friction region  74 . The brake body  70  also has an attachment portion which may be a part of a heat dissipation region, hereinafter the heat dissipation region  82 , that is disposed radially inward of the friction region  74 . The annular shape of the brake body  70  defines a central opening  84  disposed radially inward of the heat dissipation region  82 . An innermost edge or inner periphery  86  of the brake body  70  faces inward toward and extends circumferentially around the central opening  84 , thus defining the central opening. In this example, the radial inner most extent of the heat dissipation region  82  defines the inner periphery  86 . The heat dissipation region  82  is thus positioned directly adjacent the inner periphery  86 . However, additional sections or segments of an attachment portion of the brake body  70  could be disposed between the heat dissipation region  82  and the inner periphery  86 , if desired. 
     With reference to  FIGS. 7 and 8A , a plurality of attachment features are provided in the attachment portion or heat dissipation region  82  of the brake body  70 . The attachment features can be elongate holes, non-round holes, closed slots, open ended slots, or the like. In this example, the attachment features include multiple open ended slots  88  formed into the inner periphery  86  in a radial outward direction. Each slot  88  is open toward the central opening  84 . With reference to  FIGS. 7, 8A, and 8B , the brake body  70  has a first face or first axial surface, hereinafter referred to as the first axial surface  90 , which is facing in a first axial direction. The brake body  70  also has a second face or second axial surface, hereinafter referred to as the second axial surface  92 , which is facing in a second axial direction opposite the first axial surface. The heat dissipation region  82  has a first axial contact surface  94  on the brake body  70  that is facing in the first axial direction or in the same direction as the first axial surface  90 . The heat dissipation region  82  also has a second axial contact surface  96  on the brake body  70  that is facing in the second axial direction and opposite the first axial contact surface  94 . The friction region  74  has a first axial braking surface  98  on the brake body  70  that is facing in the first axial direction. The friction region  74  also has a second axial braking surface  100  that is facing in the second axial direction and opposite the first axial braking surface  98 . 
     In the disclosed example, the heat dissipation region  82  has a first thickness T (HD)  between the first axial surface  90  and the second axial surface  92  on the brake body  70  or, more specifically, between the first axial contact surface  94  and the second axial contact surface  96 . The friction region  74  has a second thickness T (F)  between the first axial surface  90  and second axial surface  92  on the brake body  70 . The first thickness T (HD) , i.e., the thickness of the heat dissipation region  82  in this example is less than the second thickness T (F) , i.e., the thickness of the friction region  74 . As shown in  FIG. 8B , the second axial braking surface  100  and the second axial contact surface  96  are co-planar with one another on the second axial surface  92  of the brake track. Thus, the second axial surface  92  is substantially flat in this example. The first axial braking surface  98 , however, and the first axial contact surface  94  are not co-planar with one another on the first axial surface  90  of the brake body  70 . Thus, the thinner heat dissipation region  82  defines a recess or pocket in the first axial surface  90  in this example. An axial shoulder  102  extends circumferentially around the brake body  70  and faces or opens to the first axial contact surface  94  on the heat dissipation region  82 . The axial shoulder  102  creates the transition between the different thicknesses of the two regions  74 ,  82 . In this example, the axial shoulder is circular, as depicted in  FIG. 7 . 
     The inner periphery  86  of the heat dissipation region  82  is not circular in this example. However, the heat dissipation region  82  in this example is a continuous circumferential structure that extends radially inward relative to the axial shoulder  102 . As shown in  FIG. 7 , the heat dissipation region  82  has a radial dimension inward from the axial shoulder  102  that varies circumferentially around the brake body  70 . The heat dissipation region  82  has taller segments  104  and shorter segments  106  that are intermittently spaced around the circumference of the heat dissipation region  82 . The plurality of slots  88  are formed into the inner periphery  86  in the taller segments  104  and the shorter segments  106  are interspersed between the slots  88  and the taller segments  104 . 
     In other examples, the heat dissipation region of the brake body may not be a continuous circumferential structure. As shown in  FIG. 9 , a brake body  110  is depicted with similar features to the brake body  70 . These similar features are identified with the same reference numbers in each example. The brake body  110  in this example, however, has a heat dissipation region  112  that is not a continuous circumferential structure. Instead the heat dissipation region  112  is a segmented structure with individual segments  114  that are circumferentially spaced apart around the brake body  110 . In this example, the opposite axial facing sides of the segments  114  each form a portion of the first and second axial contact surfaces  94 ,  96  of the heat dissipation region  112 . The segments  114  each extend radially inward from an axial shoulder  116  and are separated by gaps  118  between the segments. Each segment  114  has a radial dimension inward from the axial shoulder  116  that varies over the length of each segment. Each segment  114  is taller near the center and shorter near the adjacent gaps  118 . The plurality of slots  88  are formed into the inner periphery  86  in the taller center part of each segments  114 . 
       FIG. 10  shows another example of a brake body  120 , also with similar features to the brake body  70 . These similar features are again identified with the same reference numbers in each example. The brake body  120  in this example, however, has a different heat dissipation region  122  that is also a segmented structure with individual segments  124  that are circumferentially spaced apart around the brake body  120 . In this example, the opposite axial facing sides of the segments  124  again each form a portion of the first and second axial contact surfaces  94 ,  96  of the heat dissipation region  122 . The segments  124  each extend radially inward from an axial shoulder  126  and are separated by gaps  128  between the segments. Each segment  124  in this example has a radial dimension inward from the axial shoulder  126  that again varies over the length of each segment. Each segment  124  in this example has three taller sections  130 , one near the center of the segment  124 , separated by two shorter sections  132  and two shorter ends near the adjacent gaps  128 . The plurality of slots  88  are formed into the inner periphery  86  in the taller sections  130  of each segment  124  so that each segment includes three of the slots. As indicated by these alternate examples, the configuration and construction of the heat dissipation region  82  can vary. The thickness and the radial dimension or height of the heat dissipation region can vary. The number of gaps can vary, as can the number of segments, if any. 
     In each brake body example, the friction region  74  has a number of shaped perforations or through holes  140  and slots  142  formed through the region. The size, number, shape, arrangement, orientation, and the like of these holes  140  and slots  142  can vary considerably. These holes  140  and slots  142  can be provided to reduce material usage, reduce component weight, and/or to create air flow through the friction region  74  of the brake body  70  to increase cooling of the brake body material, if desired. These holes  140  and slots  142 , however, can be eliminated, if desired or not needed for adequate cooling of the brake rotor  60 . 
     Other examples and constructions of the brake body  70  including the friction region  74  and the heat dissipation region  82  are also possible, as will become evident to those having ordinary skill in the art. Some additional alternatives are discussed below when describing the assembled brake rotor  60  and its function. However, the first material used to form the brake body  70  can vary. In one example, the brake body  70  can be formed of a stainless steel material. The brake body material, in order to meet performance requirements, may have a hardness of about 30 HRC (Rockwell C scale hardness) or higher to avoid brake pad and debris abrasion and wear in the first and second axial braking surfaces  98  and  100 . Though possible to use a less hard material, a lower hardness may cause premature or otherwise undesirable brake wear. The brake body  70  may have a harness in a range of between about 36-42 HRC, which is achievable by heat treating a martensitic stainless steel alloy. Other first or brake body materials, however, are certainly possible. 
     The size of the brake rotor  60  and brake body  70  can also vary. In some examples, the range of diameters for the brake body  70  can be anywhere from about 100 mm to about 250 mm. The disclosed brake rotor  60  may be optimally designed for current mountain and road bike standard diameters, such as 140 mm, 160 mm, 180 mm, and 200 mm. Brake rotor diameters larger than such standard sizes may require additional or altered features to accommodate thermal growth or heat dissipation performance, as needed. 
     With reference to  FIGS. 6 and 11-12B , the carrier  78  in this example has an outer annular or circular ring or first cooling body, hereinafter referred to as the cooling body  150 . The carrier  78  also has a coupling region or hub mount, hereinafter referred to as coupling region  152 , joined to the cooling body  150  and having a plurality of bifurcated spokes  154 . Each bifurcated spoke  154  has a radial outer end joined to the cooling body  150 . Each bifurcated spoke  154  also has a pair of spoke arms  156  that, from a common radial outer end, extend in a radial inward direction but not directly toward the center of the carrier  78 . Instead, each spoke arm  156  of a bifurcated spoke  154  angles away from the other and the radial inner end is joined with the inner end of a spoke arm of an adjacent bifurcated spoke. Each such joint forms a mounting portion  158  of the coupling region  152 . Each mounting portion  158  includes a mounting hole  160  that is formed therethrough. The configuration of the mounting portions  158  and/or mounting holes  160  can vary but in this example is designed to mate with and mount the brake rotor to a hub on the front wheel  28  of the bicycle  20 . An alternate coupling portion  152  is illustrated in  FIG. 18  with a central hub  307  and a mounting interface  310 , such as a splined interface, that may be coupled with a corresponding interface of a wheel to transfer the braking forces applied to the friction region  74  of the brake rotor  60  to the wheel. 
     The disclosed carrier  78  has a six bolt pattern with six bifurcated spokes  154 , twelve spoke arms  156 , six mounting portions  158  and six mounting holes  160 . Other bolt patterns are certainly possible. Other coupling region constructions are also possible as well. In one example, the bifurcated spokes may be replaced by more conventional single spoke arms. In another example, the coupling region may define a single splined mounting arrangement at the center of the carrier for attaching the carrier to a wheel. In another example, the carrier can have a closed body configuration instead of an open ring body and spoke configuration, if desired. In any example, the coupling region is designed to mount the carrier, and thus the brake rotor to the wheel of the bicycle or other vehicle. The coupling region is configured for transmitting a braking load between the brake body and the coupling region, and thus the wheel. The braking load is a result of a braking force applied to the friction region on the brake body, as noted below when describing the operation of the brake rotor. 
     As shown in  FIGS. 12A and 12B , the coupling region  152  may also have a construction that is configured to impart strength and rigidity to the carrier  78 . In the disclosed example, the spoke arms  156  each have a non-flat construction. Each spoke arm  156  has a cavity  162  defined by a concave surface on a front side and a back side and thus has a concave cavity on both sides flanked by adjacent ribs  163 . The coupling region  152  can also be thicker radially inward toward the center of the carrier  78  nearer the mounting portions  158  and can be thinner radially outward nearer the cooling body  150 . The spoke arms  156  or bifurcated spokes  154  can also be wider along portions of their length, such as nearer the cooling body  150  as in this example. The configuration of the carrier  78  can vary. For example, the carrier  78  can have a corrugated coupling region and/or ring body, one or more flat surfaces, cooling ribs, cooling fins, weight reduction and/or cooling slots and holes, and/or other such features. Other configurations are certainly possible as well. 
     As shown in  FIGS. 6 and 11 , the cooling body  150  of the carrier  78  also has a radial outer edge  164  and a radial inner edge  166 . The cooling body  150  also has an axial front facing side  168  and an axial rear facing side  170  (see  FIGS. 12A and 12B ). In this example, at least a portion of the rear facing side  170  can be substantially flat or planar. That portion of the rear facing side  170  on the cooling body  150  can define a circumferentially continuous first contact section  172  of the heat sink  72  or the carrier  78 . The first contact section  172  is configured to contact a portion of the brake body  70  in the assembled brake rotor  60  as described below. In other examples, the rear facing side  170  can be configured to form a plurality of the first contact sections on the cooling body  150 . This can be achieved using a radially or circumferentially segmented or discontinuous ring body or by providing protruding landings or bosses on the rear facing side  170 . The first contact section  172  in this example is a radially outward circumferential section of the cooling body  150  on the rear facing side  170 . 
     In this example, the bifurcated spokes  154  extend inward from the radial inner edge  166  of the cooling body  150 . A plurality of mounting holes  174  are provided axially through the cooling body  150 . The number of mounting holes  174  coincides with the number of attachment features or slots  88  in the brake body  70  for reasons described below. The outer edge  164  of the cooling body  150  in this example is circular and thus gives the carrier  78  an overall circular shape at its radial outermost extent. The shape of the outer edge  164 , however, can be something other than circular, as long as the carrier  78  can mate with the brake body  70  and/or the second cooling body  80  to assemble the brake rotor  60 , as described below. 
     In this example, another portion of the rear facing side  170 , also shown in  FIGS. 12A and 12B , can also be substantially flat or planar, but can be out of plane with the first contact section  172 . That portion of the rear facing side  170  on the cooling body  150  can define a circumferentially continuous first mating section  176  of the heat sink  72 , the cooling body  150 , or the carrier  78 . The first mating section  176  is configured to contact a portion of the second cooling body  80  in the assembled brake rotor  60  as described below. In other examples, the rear facing side  170  can be configured to form a plurality of the first mating sections on the cooling body  150  in the same manner described above for the first contact sections. The first mating section  176  in this example is a radially inward circumferential section of the cooling body  150  on the rear facing side  170  and is disposed inward of the first contact section  172 . The cooling body  150  between the front and rear facing sides  168 ,  170  at the first mating section  176  is thicker than the cooling body between the first and second facing sides at the first contact section  172 . The first mating section  176  is out of plane in a rearward axial direction relative to the first contact section  172 . An annular, outward facing step surface  178  transitions between the two sections, as shown in  FIGS. 12A and 12B . 
     In one example, the carrier  78 , or at least part of the carrier, can be designed to form at least part of the cooling element or heat sink  72 . Thus, the carrier  78 , or at least the cooling body  150 , can be formed of a second material, which may be considered to be a heat dissipation material as compared to the first material of the brake body  70 . In one example, the entire carrier  78 , including the coupling region  152  and the ring or cooling body  150 , can be formed of aluminum or an aluminum alloy material. Thus, the entire carrier can be considered as the cooling body. The second material in this example should have good heat sink properties, such as with respect to specific heat and thermal conductivity. The heat sink characteristics or properties of the second material should be superior in comparison to the first material of the brake body  70 . In other words, the carrier material in this example should have specific heat and thermal conductivity that are greater than the first or brake body material for best heat sink functionality. Aluminum alloys may be well suited as the carrier material because the carrier can be light weight, have high strength, and provide good thermal properties. However, other heat sink materials such as copper and copper alloys also have excellent thermal properties but would add weight to the brake rotor  60 . Pure aluminum, a variety of aluminum alloys, copper, copper alloys, ceramics, or other composites or alloys are all certainly possible options for the carrier material, as are other materials, if the carrier is to provide all or part of the heat sink functionality in the brake rotor  60 . 
     With reference to  FIGS. 6, 13, and 14 , the second cooling body  80  in this example is annular or has a circular ring shape. The shape of the second cooling body  80  can vary widely from this example, however. One purpose of the second cooling body  80  is to aid in assembling the brake rotor  60 , as described below. The second cooling body  80  in this example has a radial outermost edge  180  and a radial innermost edge  182 . The second cooling body  80  also has an axial front face  184  and an opposite axial rear face  186 . In this example, at least the front face  184 , or a portion thereof, can be substantially flat or planar. That portion of the front face  184  can define a circumferentially continuous second contact section  188  on the heat sink  72  or the second cooling body  80  that is configured to contact a portion of the brake body  70  in the assembled brake rotor  60  as described below. In other examples, the front face  184  can be configured to form a plurality of the second contact sections on the second cooling body  80 . This can be done using a radially or circumferentially segmented or discontinuous body or by providing protruding landings or bosses on the front face  184 . The second contact section  188  in this example is a radially outward circumferential section of the second cooling body  80  on the front face  184 . 
     In this example, another portion of the front face  184  (also shown in  FIGS. 14 and 15B ) can also be substantially flat or planar and co-planar with the second contact section  188 . That portion of the front face  184  on the second cooling body  80  can define a circumferentially continuous second first mating section  190  of the heat sink  72  or the second cooling body  80 . The second mating section  190  is configured to contact a portion of the carrier  78  or the cooling body  150  in the assembled brake rotor  60  as described below. In other examples, the front face  184  can be configured to form a plurality of the second mating sections on the second cooling body  80  in the same manner described above for the first and second contact sections. The second mating section  190  in this example is a radially inward circumferential section of the second cooling body  80  on the front face  184  and is disposed inward of the second contact section  188 . 
     In alternate examples, the axial front and rear facing sides  168 ,  170  of the cooling body  150  on the carrier  78  can both be planar or can both be non-planar. The first contact section  172  and the first mating section  176  can lie in the same plane or can lie out of plane but with the first mating section  176  offset toward the front side. Also, one or both of the front and rear faces  184 ,  186  of the second cooling body  80  can also be non-planar or only one may be planar. The second contact section  188  and the second mating section  190  can lie in different planes and can be offset in either the front or rear direction. 
     In the disclosed example, the second cooling body  80  also has a plurality of fastener holes  192  formed axially through the body. The number of the holes  192  again corresponds to the number of slots  88  in the brake body  70  and the mounting holes  174  in the carrier to facilitate assembly of the brake rotor as described below. 
     Another purpose of the second cooling body  80  in this example may be to form all of the heat sink  72 , or at least part of the heat sink in combination with the carrier  78  or the cooling body  150  of the carrier. Thus, the second cooling body  80  can be formed of a third material, which may be considered to be a heat dissipation material as compared to the first material of the brake body  70 . In one example, the second cooling body  80  can be formed of aluminum or an aluminum alloy material. The third material in this example should also have good heat sink properties, such as with respect to specific heat and thermal conductivity. The heat sink characteristics or properties of the third material should therefore have specific heat and thermal conductivity that are greater than the first or brake body material for best heat sink functionality. Aluminum alloys may be well suited as the second cooling body material because the second cooling body can be light weight, have high strength, and provide good thermal properties. However, as with the carrier  78  or the cooling body  150 , pure aluminum, a variety of aluminum alloys, copper, copper alloys, ceramics, or other composites or alloys are all certainly possible options for the second cooling body material, if the second cooling body is to provide all or part of the heat sink functionality in the brake rotor  60 . As noted above, the second and third material can be the same material or can be substantially the same material with similar specific heat and thermal conductivity properties. 
     The assembled brake rotor  60  is now described with reference to  FIGS. 2-6 and 15A-15C  and to the foregoing descriptions of the brake body  70 , carrier  78 , and second cooling body  80 . In this example, the carrier  78  is positioned concentric with the brake body  70  over the central opening  84  on the first axial surface  90 . At least the coupling region  152  and the first mating section  176  of the carrier  78  may be disposed within the central opening  84  in the brake body  70 . The radial outer edge  164  of the cooling body  150  faces and is seated adjacent and radially inward of the axial shoulder  102 . The first contact section  172  on the rear facing side  170  of the cooling body  150  is borne against the first axial contact surface  94  of the heat dissipation region  74  on the brake body  70 . The mounting holes  174  on the carrier  78  are aligned with the slots  88  on the brake body  70 , as shown in  FIGS. 15A and 15B . The second cooling body  80  is positioned concentric with the brake body  70  on the second axial surface  92 . At least the second mating section  190  of the second cooling body  80  may be disposed radially within the central opening  84  of the brake body  70 . The second contact section  188  on the front face  184  of the second cooling body  80  is borne against the second axial contact surface  96  of the heat dissipation region  74  on the brake body  70 . The fastener holes  192  in the second cooling body  80  are aligned with the slots  88  in the heat dissipation region and the mounting holes  174  on the carrier, also as shown in  FIGS. 15A and 15B . 
     As best illustrated in  FIGS. 6, 15A, and 15B , fasteners  194  can then be used to secure the components together. In one example, the fasteners  194  can be stainless steel rivets. However, other fastener type, fastener materials, and/or fastening techniques may be utilized, if suitable and desired, to assemble the brake rotor  60 . In the assembled brake rotor  60 , part of the brake body  70  is captured or sandwiched between portions of the carrier  78  and portions of the second cooling body  80 . More specifically, the first and second axial contact surfaces  94 ,  96  on the attachment portion or heat dissipation region  74  of the brake body  70  are in contact with and captured between the first contact section  172  of the carrier and the second contact section  188  of the second cooling body. Portions of the carrier  78  and second cooling body  80  are in direct contact with one another in a mating region that is radially inward of the heat dissipation region  74  and its inner periphery  86 . More specifically, the first mating section  176  on the carrier  78  and the second mating section  190  on the second cooling body are borne against one another in the mating region, as depicted in  FIGS. 15B and 15C . 
     The combination of the carrier  78 , or the cooling body  150 , and second cooling body  80  creates a sizable cooling element or heat sink  72  that is directly coupled to the brake body  70 . In this example, at least a portion of the heat sink  72 , i.e., the cooling body  150  of the carrier  78 , is in contact with the first axial contact surface  94  around the brake body  70  for 360 degrees of the circumference of the heat dissipation region  74 . This is because both the first axial contact surface  94  and/or the heat dissipation region  74  and the first contact section  172  of the carrier  78  are circumferentially continuous and substantially planar. Likewise, at least a portion of the heat sink  72 , i.e., the second cooling body  80 , is in contact with the second axial contact surface  96  around the brake body  70  for 360 degrees of the circumference of the heat dissipation region  74 . This is again because the second axial contact surface  96  and/or the heat dissipation region  74  and the second contact section  188  are circumferentially continuous and substantially planar. 
     In other examples, the heat sink  72 , i.e., the carrier  78 , the second cooling body  80 , or both, may be in contact with the first axial contact surface  94 , the second axial contact surface  96 , or both, over less than 360 degrees around the brake body but for at least a majority of the circumference of the heat dissipation region. For example, one of the brake bodies  110  or  120  could be used, which have segmented or discontinuous heat dissipation regions. The brake body  110  of  FIG. 9  has twelve segments  114  of the heat dissipation region  112  and twelve gaps  118 . Each of the twelve gaps in one example is 5 degrees of the circumference of the brake body  110 . Thus, the heat sink  72  contacts the heat dissipation region  112  over 300 degrees of the circumference of the brake body  110 . The brake body  120  has four elongate segments  124  in the heat dissipation region  122  and has four 5 degree gaps separating the segments. Thus, the heat sink  72  contacts the heat dissipation region  122  over 340 degrees of the circumference of the brake body  120 . In either example, the heat sink contact around the brake body would be over a majority of the circumference, though less than 360 degrees, and still be quite effective in dissipating heat from the brake body through the heat sink. In other examples, combinations of the heat dissipation region contact surfaces and the cooling body and second cooling body contact sections may yield  360  heat sink contact around the brake body though neither the cooling body nor the second cooling body do so alone. In still another example, the heat sink contact with the brake body may amount to 300 degrees or more of circumferential contact around the brake body. In yet another example, the heat sink contact with the brake body may be substantially all, but not entirely all, of the circumference around the brake body. Substantially all would mean at least one break one location where there is no circumferential contact between the heat sink and brake body. 
       FIGS. 16, 17A, and 17B  show one alternate example of a portion of the heat sink where the heat sink portion is corrugated or otherwise non-planar or non-flat prior to assembly. In this example, a second cooling body  200  has contact surfaces that are not flat or planar before assembly. These surfaces, however, can be configured to become flat against the contact surfaces of the brake body when the brake rotor is assembled. In this example, the second cooling body  200  is depicted in  FIGS. 16 and 17A  as an annular body or ring shape. The second cooling body  200  has a radial outermost edge  202 , a radial innermost edge  204 , a front face  206 , a rear face  208 , and fastener holes  210  through the body, similar to the second cooling body  80  described previously. 
     However, in this example, the second cooling body  200  is not completely flat or planar, as can be seen in  FIGS. 17A and 17B . The second cooling body  200  can include a plurality of discreet or subtle corrugations, waves, or non-planar features around the body in a circumferential direction. In the example shown in  FIG. 16 , radial extending shade lines C are shown spaced circumferentially between and among the fastener holes  210  around the annular body. The lines C may represent a curvature transition line to indicate a subtle convex or concave curve in the second cooling body  200  at the location of each line. As shown in  FIG. 17B , this subtle curve can result in a portion of the cooling body  200  being out of plane by a dimension or gap D relative to adjacent portions of the cooling body. The location, number, and out of plane dimension D can vary. 
     The second cooling body  200  can be assembled via the fasteners  194  to complete a brake rotor that is otherwise identical to the brake rotor  60 . When assembled, the corrugated second cooling body  200  can become flat under compression applied by the fasteners  194 . The forcibly flattened second cooling body  200  can thus apply or impart a preload against the fasteners  194  and between the front face  206  on the second cooling body  200  and the second axial contact surface  94  on the heat dissipation region  74  of the brake body  70 . The preload can aid in preventing the fasteners  194  from inadvertently backing out. The preload can also aid in increasing and maintaining thermal surface contact between the second cooling body  200  and the carrier  78  in the mating region and between the second cooling body and the brake body  70  in the heat dissipation region  74 . This may be particularly useful as these parts thermally grow and deform under heavy or extreme braking conditions during use. 
     The disclosed second cooling bodies can vary in configuration and construction, if desired, from the simple annular bodies disclosed above. The second cooling body can have a shape other than a circular ring or annular shape. The thickness of the second cooling body can vary over portions of the second cooling body in a radial direction, a circumferential direction, or both. As described, the second cooling body can be corrugated, non-planar, slightly conical, wavy, or otherwise non-flat in a pre-assembled condition. Such non-flat configurations can thus render the second contact section or sections of the front face to be non-flat as well, which can become flat when secured by the fasteners. The second cooling body can instead be a flat ring shape, as in the disclosed example of  FIGS. 13 and 14 . The second cooling body can also include other features and characteristics to reduce weight, reduce material usage, improve heat conduction, absorption, and/or dissipation, and the like. For example, the second cooling body can include cooling ribs, fins, additional holes, added slots, or other such features. 
     In other examples, it is possible that the first contact section or sections on the carrier can also be non-flat in the same manner prior to assembling the brake rotor. Thus, the ring shaped cooling body of the carrier may have a subtle non-flat, corrugated, non-planar, or wavy construction as well. In still other examples, either or both of the cooling body and second cooling body can be so constructed. However, as with the second cooling body, the carrier cooling body can become flat or substantially planar when the brake rotor is assembled. It is further possible to fabricate the brake body such that the first and/or second axial contact surfaces  94 ,  96  on the heat dissipation region  82  may also be non-flat, corrugated, non-planar, wavy, or the like. These contact surfaces can be so constructed whether or not the aforementioned carrier and second cooling body are so constructed. 
     In the disclosed example, the brake body  70  includes twelve slots  88 . The carrier correspondingly has twelve mounting holes  174  and the second cooling body correspondingly has twelve fastener holes  192 . Likewise, the brake rotor has twelve fasteners  194 , for example rivets, received through the mounting holes  174 , slots  88 , and fastener holes  192  to assemble the rotor. The various slots and holes are arranged in a circumferential alignment with one another and are spaced equidistant from one another around the brake rotor. However, any number more or less than twelve, and many different arrangements of the fasteners, holes, and slots may be used in order to assemble the brake rotor  60 . 
     The disclosed construction of the front brake rotor  60  is equally applicable to the rear brake rotor  62 , as noted above. The brake rotors disclosed herein are heat dissipating rotors. In the examples shown and described, the brake rotor  60  has a stainless steel brake body, an aluminum alloy heat sink, i.e., an aluminum alloy carrier and an aluminum alloy second cooling body, and stainless steel rivets. The brake body is in contact with the heat sink, i.e., both the carrier and the second cooling body at a heat dissipation region around a majority of a circumference of the brake body. This contact allows for and encourages heat transfer from the stainless steel brake body to the heat sink body or bodies. The slots  88  in the heat dissipation region  82  on the brake body  70  are configured and provided to permit relative radial expansion between the brake body and heat sink. As the brake body heats up and expands or grows relative to the heat sink, the slots  88  allow the rivets or fasteners  194  to move slightly in a radial direction relative to one another. The aluminum heat sink, i.e., the carrier and second cooling body act as a heat sink in transferring or conducting excess heat from the brake body to the heat sink. In the disclosed example, both the carrier and the second cooling body contact surfaces of the brake body and contact one another. Thus, both components can very effectively transfer heat from the brake body to the heat sink. 
     The disclosed heat dissipating brake rotors can be used as a lightweight component on bicycles to lower the operating temperatures in a disc brake system. Extreme braking condition may result from greater deceleration rates, steeper downhill gradients, and higher speeds. Braking friction under these conditions generates higher wattages, which results in higher brake component temperatures. Therefore, there is a need for the disclosed brake rotors, which can efficiently remove excess heat from the brake body of the braking system, hold a significant portion of the brake body generated heat, and release the heat to the surrounding environment through convection and radiation. 
     The disclosed heat sink can be fabricated from different suitable heat ink materials. Aluminum and aluminum alloys have high relative specific heat and thermal conductivity properties, which renders such materials particularly useful for heat sink applications. Aluminum and aluminum alloys are also relatively high strength materials, which renders them particularly useful for the brake rotors disclosed herein. 
     During use of the disclosed bicycle and brake rotors, a rider applies the brakes to control vehicle speed. The brake pads make contact with the friction region of the brake rotors, which, under heavy or extreme braking conditions, generates substantial friction in controlling the rotational speed of the brake rotors and thus the wheels. The friction at the friction region on the brake body converts the bicycle&#39;s kinetic energy into heat. A portion of the heat is transferred into the brake pads, but a greater portion of the heat is transferred into the brake body. 
     As the brake body heats up, its larger diameter grows through thermal expansion. The brake body attachment features or slots allow for radial movement of the rivets. Thus, the slots render the brake body unconstrained in the radial direction, allowing the brake body to thermally grow. This feature can aid in avoiding heat warping or deformation of the brake body that can otherwise occur in a conventional over-constrained round hole style rivet mount. Also, the aluminum alloy carrier and second cooling body are in contact with the brake body and function as a heat sink. The carrier and second cooling body absorb or conduct heat from the brake body through their mutual contact surfaces at the heat dissipation region. The aluminum alloy carrier and second cooling body can share, through their contact in the mating region, the temperature or heat of the brake body and can hold a portion of the heat. A portion of the heat can be dissipated or released through the external surface area of the carrier and second cooling body. Thus, the surface area of these parts can be designed to increase or maximize the surface area of the heat sink. This heat is transferred through convection and radiation to the surrounding air and environment. 
     When the rider releases the brakes, the brake system ceases to generate heat. However, the brake rotor, with its now elevated temperature, can continue to transfer heat to the surrounding environment, as well as to the heat sink. As time passes without the brakes being applied, the brake rotor continues to release heat, approaching the temperature of the surrounding environment until the next braking event. 
     One existing brake rotor design uses aluminum in the brake body itself in an attempt to dissipate heat more efficiently. However, it is the brake body that experiences the highest temperatures in a brake system. Testing has shown that the aluminum in the brake body can melt during heavy or extreme braking conditions. This melting of the aluminum brake body material deforms the brake body, compromises its strength, and contaminates the brake surface with molten aluminum. The disclosed brake rotors do not use aluminum in the brake body where the temperatures are the greatest, thus improving the rotor&#39;s resistance from melting, but achieve the advantages and benefits of using a high thermal conductivity material. 
     Another existing brake rotor design uses a stainless steel brake body with aluminum material attached on one side of the brake body and in between structural arms of a mounting hub. Adding the aluminum material reduced the contact surface area of the brake body, reduced the volume of aluminum in the proximity of the brake body, and therefore reduced the heat sink capabilities of the material with the brake body. In comparison, the disclosed brake rotors have aluminum heat sink contact on both sides of the brake body, can have a majority or 360 degree circumferential contact with the brake body but radially inward of the friction region, and have a much greater volume of aluminum in proximity to the brake body, all of which maximize the heat sink capabilities of the brake rotor design. 
     Both of the foregoing existing brake rotor designs also employ rivets that join the parts of the brake rotor through circular holes. The circular holes over-constrain the brake body, thus not allowing for thermal growth. The disclosed brake rotors improve upon this disadvantage by using slots in the brake body for receiving the rivets to assemble the brake rotor. The slots allow the brake body to thermally grow unconstrained, which greatly assist in avoiding in-use warping and permanent deformation of the brake body. 
     The disclosed brake rotors may be particularly well suited for use on mountain bicycles. However, the brake rotor may also be used on other at least partially human-powered vehicles such as on light weight road bikes, off-road bicycles, road bicycles, and electric motor assisted bikes. Braking applications above this size or weight range of vehicles could require design modifications to improve strength. Braking applications below this size or weight range of vehicles may not require the heat dissipation performance provided by the disclosed brake rotors. 
     The illustrations of the embodiments and examples described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of ordinary skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may or may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive. 
     While this specification contains many specifics, these should not be construed as limitations on the scope of the inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are apparent to those of skill in the art upon reviewing the description. 
     The Abstract is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter. 
     It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the invention. The claims should not be read as limited to the described order or elements unless stated to that effect. Therefore, all embodiments that come within the scope and spirit of the following claims and equivalents thereto are claimed as the invention.