[0001] The present application claims priority from Australian Provisional Application No. 2016903233 titled "A WHEEL HUB AND BRAKE ASSEMBLY FOR A BICYCLE" filed on 15 August 2016, the content of which is hereby incorporated by reference in its entirety.

Background of the Invention

[0002] The present invention relates to a wheel hub for a bicycle and brake assembly therefor, and in one example, to a disc brake assembly for a bicycle that may be integrated with a wheel hub.

Description of the Prior Art

[0003] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0004] Bicycles are typically fitted with either rim brakes or disc brakes and some older bikes have employed hub brakes.

[0005] Rim brakes employ a pair of friction pads located either side of a wheel rim that are operable to clamp the rim of the rotating wheel to apply a braking force thereto. Rim brakes are typically cable actuated (but can be hydraulically actuated) by a rider squeezing a brake lever attached to the handlebars of the bike which causes the brake caliper arms connected to the brake shoes to move together so that the pads squeeze the rim. Rim brakes tend to be lightweight and relatively inexpensive; however performance in the wet can be poor as the brake components and rim are exposed to the environment. In addition, the braking surface on the rims can wear which can lead to rim failure if not properly maintained. Due to positioning of the brake caliper typically above the front fork, the aerodynamic performance of the bicycle is often compromised by the use of rim brakes. [0006] Discs brakes employ a rotor disc attached externally to the wheel hub that rotates with the wheel. Brake calipers are mounted to the frame or fork and include pads that are designed to frictionally engage with the rotor disc to thereby brake the wheel. Disc brakes offer a number of potential advantages over rim brakes including increased stopping power, modulation, control and performance in wet weather. The world governing body for sports cycling, the Union Cycliste Internationale (UCI), allowed disc brakes to be trialled by professional road racing teams in 2016. However, in some races, riders have sustained serious injuries resulting from the rotor discs, which typically have a sharp edge. These injuries have included serious lacerations to limbs as a result of riders crashing and being sliced by the spinning rotors attached to the bikes of other riders.

[0007] There is therefore a serious concern about rider safety when disc brakes are used in professional road cycling, in which riders typically ride in tightly bunched groups and crashes frequently occur. In addition to the risk of being cut by the rotor disc, another risk with exposed rotors is that due to the heat dissipated during braking, the disc can get very hot which can lead to burns if accidentally touched.

[0008] Furthermore, as with rim brakes, the brake caliper used for disc brakes typically impedes the aerodynamic performance of the bicycle, due to its position in the air flow path. Further to this, the brake disc itself is typically located outside the wheel in a poor aerodynamic position.

[0009] It is against this background, and the problems and difficulties associated therewith, that the present invention has been developed.

Summary of the Present Invention

[0010] In one broad form, an aspect of the present invention seeks to provide a brake assembly for a bicycle, the brake assembly including:

a) a wheel hub, including:

i) a wheel axle defining an axis of rotation for the wheel; and, ii) a hub body rotatably coupled to the axle for rotation about the axis of rotation, the hub body including a hub flange extending around the perimeter of the hub body proximate an end thereof;

b) a brake disc mounted to the hub flange so that an outer periphery of the brake disc is at least partially shielded by the hub flange; and,

c) a brake caliper for applying a braking force to the brake disc, the brake caliper having a caliper housing arranged to at least partially surround a portion of an inner periphery of the brake disc.

[0011] In one embodiment, the hub flange includes:

a) a plate portion that projects radially outward from the hub body;

b) a sidewall portion that projects away from an outer edge of the plate portion in a direction of elongation of the hub body; and,

c) a lip portion that projects radially outward from a terminal edge of the sidewall portion.

[0012] In one embodiment, the brake disc is mounted to the lip portion of the hub flange.

[0013] In one embodiment, the brake disc includes mounting tabs that project away from the outer periphery of the brake disc to facilitate mounting of the brake disc to the hub flange.

[0014] In one embodiment, the brake disc is substantially annular.

[0015] In one embodiment, the outer periphery of the brake disc is at least partially shielded by the hub flange as a result of at least one of:

a) the brake disc being axially located so as to be disposed entirely within the hub flange;

b) the brake disc being axially located so as to be entirely outside the hub flange by no more than a distance corresponding to the thickness of the brake disc; and, c) a width or diameter of the hub flange being greater than an outer width or diameter of the brake disc.

[0016] In one embodiment, the brake caliper includes a caliper mount that is rotationally fixed with respect to the wheel hub. [0017] In one embodiment, the caliper mount is attached directly to the wheel hub.

[0018] In one embodiment, the caliper mount includes at least one support arm that is coupled to the caliper housing.

[0019] In one embodiment, the at least one support arm is coupled to the caliper housing by at least one pin which provides a degree of lateral float for the caliper housing relative to the caliper mount.

[0020] In one embodiment, the at least one support arm has a support arm lug positionable between a pair of spaced apart caliper housing lugs, each of the lugs having an aperture for receiving the pin therethrough.

[0021] In one embodiment, the caliper housing houses one or more hydraulic cylinders that are operatively disposed on one side of the brake disc for actuating one or more pistons that act to urge a pair of brake pads on either side of the brake disc into clamping engagement with braking surfaces of the brake disc to apply braking forces thereto.

[0022] In one embodiment, in use, the caliper housing floats laterally so that braking forces exerted on opposing braking surfaces of the brake disc are balanced.

[0023] In one embodiment, the one or more hydraulic cylinders are disposed on an outer side of the brake disc so as to be outside of the hub flange.

[0024] In one embodiment, the at least one support arm is coupled to the caliper housing by at least one bolt which fixes the caliper housing with respect to the at least one support arm.

[0025] In one embodiment, the at least one support arm has a support arm lug positionable in abutment with a caliper housing lug, each of the lugs having an aperture for receiving the bolt therethrough.

[0026] In one embodiment, the caliper housing houses one or more hydraulic cylinders that are operatively disposed on opposing sides of the brake disc for actuating pistons which urge a pair of brake pads on either side of the brake disc into clamping engagement with braking surfaces of the brake disc to apply braking forces thereto. [0027] In one embodiment, one or more cylinders are disposed on an inner side of the brake disc within a recessed portion of the hub flange and one or more opposing cylinders are disposed on an outer side of the brake disc so as to be outside of the hub flange.

[0028] In one embodiment, the caliper mount is attached directly to a portion of the bicycle frame.

[0029] In another broad form, an aspect of the present invention seeks to provide a wheel hub for a bicycle, the wheel hub including a hub body rotatable about an axle, the hub body including a hub flange extending around the perimeter of the hub body proximate an end thereof, the hub flange adapted for mounting a brake disc thereto so that an outer periphery of the brake disc is at least partially shielded by the hub flange.

[0030] In one embodiment, the hub flange includes:

a) a plate portion that projects radially outward from the hub body;

b) a sidewall portion that projects away from an outer edge of the plate portion in a direction of elongation of the hub body; and,

c) a lip portion that projects radially outward from a terminal edge of the sidewall portion.

[0031] In one embodiment, the brake disc is mountable to the lip portion of the hub flange.

[0032] In one embodiment, the outer periphery of the brake disc is at least partially shielded by the hub flange as a result of at least one of:

a) the brake disc being axially located so as to be disposed entirely within a recessed portion of the hub flange;

b) the brake disc being axially located so as to be entirely outside the hub flange by no more than a distance corresponding to the thickness of the brake disc; and, c) a width or diameter of the hub flange being greater than an outer width or diameter of the brake disc.

[0033] In a further broad form, an aspect of the present invention seeks to provide a bicycle wheel assembly, the wheel assembly including:

a) a wheel hub, including: i) a wheel axle defining an axis of rotation for the wheel; and,

ii) a hub body rotatably coupled to the axle for rotation about the axis of rotation, the hub body including a hub flange extending around the perimeter of the hub body proximate an end thereof;

b) a bicycle wheel coupled to the wheel hub by a plurality of spokes;

c) a brake disc mounted to the hub flange so that an outer periphery of the brake disc is at least partially shielded by the hub flange; and,

d) a brake caliper for applying a braking force to the brake disc, the brake caliper having a caliper housing arranged to at least partially surround a portion of an inner periphery of the brake disc.

[0034] In yet a further broad form, an aspect of the present invention seeks to provide a bicycle including a brake assembly as previously described.

[0035] It will be appreciated that the broad forms of the invention and their respective features can be used in conjunction, interchangeably and/or independently, and reference to separate broad forms in not intended to be limiting.

Brief Description of the Drawings

[0036] Non-limiting examples of the present invention will now be described with reference to the accompanying drawings, in which: -

[0037] Figure 1A is a perspective view of an example of a bicycle wheel having a brake assembly mounted thereto;

[0038] Figure IB is a side view of the bicycle wheel of Figure 1 A;

[0039] Figure 2 is a perspective view of an example of the brake assembly depicted in Figure 1A;

[0040] Figure 3 A is a perspective partial cut-away view of the brake assembly of Figure 2;

[0041] Figure 3B is an exploded view of the brake assembly as depicted in Figure 3 A;

[0042] Figure 4 is a sectional top view of the brake assembly shown in Figure 2 taken through the centreline of the wheel hub;

[0043] Figure 5A is a perspective view of a further example of a bicycle wheel having a brake assembly mounted thereto; [0044] Figure 5B is a side view of the bicycle wheel of Figure 5 A;

[0045] Figure 6 is a perspective view of an example of the brake assembly depicted in Figure 5A;

[0046] Figure 7 A is a perspective partial cut-away view of the brake assembly of Figure 6;

[0047] Figure 7B is an exploded view of the brake assembly as depicted in Figure 7A; and,

[0048] Figure 8 is a sectional top view of the brake assembly shown in Figure 6 taken through the centreline of the wheel hub.

Detailed Description of the Preferred Embodiments

[0049] An example of a brake assembly 100 for a bicycle will now be described with reference to Figures 1 A to 2.

[0050] The brake assembly 100 is integrated with a wheel hub 110 and forms part of a bicycle wheel assembly 10. The wheel hub 110 is connected to a wheel rim 20 by a plurality of spokes 40 which may be fitted in a conventional manner to flange portions of the hub 110. Although in Figures 1 A and IB there is shown a wheel having a deep dish rim, this is for purposes of illustration only and it is to be understood that the brake assembly 100 may be fitted to any desired style of wheel rim.

[0051] In this example, the brake assembly 100 includes a wheel hub 110 including a wheel axle (not shown) defining an axis of rotation for the wheel 10. The wheel hub 110 further includes a hub body 111 rotatably coupled to the axle for rotation about the axis of rotation. The hub body 111 further includes a hub flange 120 extending around the perimeter of the hub body 111 proximate an end 112 thereof. Whilst typically, the hub flange 120 is integral with the hub body 111, in other examples, the hub flange 120 may be a separate component which is secured to the hub body 111.

[0052] A brake disc 140 is mounted to the hub flange 120 so that an outer periphery 144 of the brake disc 140 is at least partially shielded by the hub flange 120 as will be described in further detail below. The brake disc 140 is formed from a thin plate providing a pair of opposing braking surfaces and is typically formed as an annular ring. The brake assembly 100 further includes a brake caliper 150 for applying a braking force to the brake disc 140, the brake caliper 150 having a caliper housing 152 arranged to at least partially surround a portion of an inner periphery 142 of the brake disc 140.

[0053] The above described arrangement provides a number of advantages.

[0054] Firstly, the brake assembly 100 provides a disc brake having improved safety in comparison to conventional disc brake systems in which the outer edge of the rotor disc is exposed. The above described disc brake is at least partially shielded by the hub flange which is designed to reduce the exposure of the outer edge of the disc, thereby reducing the risk of injury, in particular by way of laceration or burns. Accordingly, this arrangement provides a safer alternative to known disc brakes.

[0055] In the above described brake assembly 100, the brake caliper 150 is operatively arranged about an inner periphery of the disc which is opposite to a conventional disc brake in which the caliper is arranged about an outer periphery of the disc. This arrangement permits the brake disc to be in close proximity to the hub flange enabling it to be at least partially shielded by the hub flange.

[0056] In addition, mounting the caliper inside the brake disc in this way also provides an aerodynamic benefit as at least part of the caliper is disposed within the hub flange and out of the aerodynamic flow. Further to this, the brake disc is also substantially out of the air flow around the wheel which provides an aerodynamic benefit compared to standard disc brakes in which the disc is positioned outside of the wheel in the air flow.

[0057] Whilst improving safety and aerodynamic performance, the present design also ensures that braking forces generated by the assembly are at least equal to braking forces generated by conventional disc brakes. Braking performance is therefore not compromised by this improved arrangement.

[0058] In contrast to rim brakes, the above described arrangement also improves wheel life by eliminating the brake friction wear on wheel rims which in some cases can lead to catastrophic wheel failure. As the rims are not used in braking, the rim section can be made thinner which can enable the wheel rim to be lighter than rims designed for use with rim brakes. [0059] The above described arrangement may also be retrofitted to existing wheels, by simply replacing an existing hub with a hub and brake assembly as described.

[0060] A number of further features will now be described.

[0061] In one example, the hub flange 120 includes a plate portion that projects radially outward from the hub body, a sidewall portion that projects away from an outer edge of the plate portion in a direction of elongation of the hub body, and a lip portion that projects radially outward from a terminal edge of the sidewall portion. Accordingly, the hub flange 120 may therefore form a type of cage structure that provides an open cavity in which part of the disc and/or caliper may be located to assist in shielding the outer edge of the disc and improving aerodynamic performance.

[0062] Typically, the brake disc 140 is mounted to the lip portion of the hub flange 120. In one example, the brake disc 140 includes mounting tabs that project away from the outer periphery of the brake disc 140 to facilitate mounting of the brake disc 140 to the hub flange 120. Whilst the mounting tabs may simply abut the outer surface of the lip, in other examples, the lip may have complementary recessed portions for receiving the mounting tabs therein so that the outer surface of the disc is flush with the outer surface of the lip portion of the hub flange 120. In other examples, the disc may be mounted entirely within the hub flange.

[0063] The outer periphery (i.e. outer edge) of the brake disc 140 may be at least partially shielded by the hub flange 120 in a number of ways. In one example, the brake disc may be axially located so as to be disposed entirely within the hub flange. The outer edge of the disc would then be fully shrouded by the sidewall portion of the hub flange.

[0064] In the illustrated example, the brake disc 140 is axially located so as to be entirely outside the hub flange 120 by no more than a distance corresponding to the thickness of the brake disc 140. This is the case for example, when the brake disc has mounting tabs which are in abutment with the outer surface of the lip portion of the hub flange. In this example, although the outer periphery is not disposed axially within the hub flange, it is in close proximity thereto and remains substantially shielded by the hub flange. Furthermore, a width or diameter of the hub flange is greater than an outer width or diameter of the brake disc. The brake disc is therefore disposed within a peripheral boundary of the hub flange so that exposure of the outer edge is minimised.

[0065] Typically, the brake caliper includes a caliper mount that is rotationally fixed with respect to the wheel hub. In one example, the caliper mount is attached directly to the wheel hub. The connection between the caliper mount and the wheel hub may be for example through a spline, keyway or other suitable structure that prevents relative rotation so as to transmit braking torque to the through axle.

[0066] Alternatively, the caliper mount may be attached directly to a portion of the bicycle frame, such as the fork at a position proximate the wheel hub for front wheel brakes and directly to the rear of the bike frame for rear brake applications.

[0067] Typically, the caliper mount includes at least one support arm that is coupled to the caliper housing. The at least one support arm typically projects radially away from the axis of rotation and is coupled to the caliper housing.

[0068] In one example, the at least one support arm is coupled to the caliper housing by at least one pin which provides a degree of lateral float for the caliper housing relative to the caliper mount. In this arrangement, the at least one support arm has a support arm lug positionable between a pair of spaced apart caliper housing lugs, each of the lugs having an aperture for receiving the pin therethrough.

[0069] In this example, referred to as the 'floating caliper' example, the caliper housing houses one or more hydraulic cylinders that are operatively disposed on one side of the brake disc for actuating one or more pistons that act to urge a pair of brake pads on either side of the brake disc into clamping engagement with braking surfaces of the brake disc to apply braking forces thereto. In operation, the caliper housing floats laterally so that braking forces exerted on opposing braking surfaces of the brake disc are in balance.

[0070] Furthermore, the one or more hydraulic cylinders are disposed on an outer side of the brake disc so as to be outside of the hub flange. With the cylinders in this position, the profile of the inner portion of the caliper housing (that is disposed in closer proximity to the hub) can be minimised therefore permitting a compact arrangement and reducing the required depth of the hub flange.

[0071] In another example, the at least one support arm is coupled to the caliper housing by at least one bolt which fixes the caliper housing with respect to the at least one support arm. In this example, the at least one support arm has a support arm lug positionable in abutment with a caliper housing lug, each of the lugs having an aperture for receiving the bolt therethrough. In this arrangement, the caliper housing is fixed relative to the caliper mount and unable to float as in the previously described example.

[0072] As such, the caliper housing houses one or more hydraulic cylinders that are operatively disposed on opposing sides of the brake disc for actuating pistons which urge a pair of brake pads on either side of the brake disc into clamping engagement with braking surfaces of the brake disc to apply braking forces thereto. In this example, referred to as the "opposing cylinder" example, the cylinders are able to hydraulically balance the clamping forces on either side of the brake disc and as such the caliper does not need to float in order to centralise alignment with the brake disc.

[0073] In this example, one or more cylinders are disposed on an inner side of the brake disc within a recessed portion of the hub flange and one or more opposing cylinders are disposed on an outer side of the brake disc so as to be outside of the hub flange. As a result of the one or more cylinders disposed on an inner side of the brake disc within a recessed portion of the hub flange, the caliper housing for the opposing cylinder design must be wider than the caliper housing of the floating caliper design. Also, the depth of the hub flange must be greater to accommodate the additional cylinder(s) disposed on the inner side of the brake disc.

[0074] In a broad aspect, there is also provided a wheel hub for a bicycle, the wheel hub including a hub body rotatable about an axle, the hub body including a hub flange extending around the perimeter of the hub body proximate an end thereof, the hub flange adapted for mounting a brake disc thereto so that an outer periphery of the brake disc is at least partially shielded by the hub flange in a manner previously described. It will be appreciated that in order to at least partially shield the brake disc, the hub flange is significantly wider than a traditional hub flange to which the spokes are attached.

[0075] In another broad aspect, there is provided a bicycle wheel assembly, the wheel assembly including a wheel hub, including a wheel axle defining an axis of rotation for the wheel, and a hub body rotatably coupled to the axle for rotation about the axis of rotation, the hub body including a hub flange extending around the perimeter of the hub body proximate an end thereof. A bicycle wheel is coupled to the wheel hub by a plurality of spokes. The assembly further includes a brake disc mounted to the hub flange so that an outer periphery of the brake disc is at least partially shielded by the hub flange, and a brake caliper for applying a braking force to the brake disc, the brake caliper having a caliper housing arranged to at least partially surround a portion of an inner periphery of the brake disc.

[0076] The brake assembly 100 having a "floating caliper" shall now be described in further detail with reference to Figures 2, 3 A, 3B and 4.

[0077] As previously described, the brake assembly 100 includes a wheel hub 1 10 having a cylindrical body or shell 111. The hub 110 includes a first flange 113 at a first end to which spokes 40 of the bicycle wheel 10 are attached. Proximate a second end 112, the hub 110 includes a second flange 120 that radially projects away from the hub body 111. As shown in the figures, the second flange 120 defines a significantly larger diameter than the first flange. Typically, the ratio between the diameter of the second and first flanges is between, but not limited to, 2: 1 to 3: 1.

[0078] In the example shown, the second flange 120 (referred to herein as the "hub flange") includes a radially projecting plate portion 122 which typically includes a series of cut-outs 123 such that the plate portion 122 defines a series of spaced apart arm or strut members 122.1 that extend away from the hub body 111 towards an outer edge 122.2 of the plate portion 122. A sidewall portion 124 projects away from an outer edge 122.2 of the plate portion 122 in a direction of elongation of the hub body 111 and terminates in an out-turned lip portion 126 that provides a mating interface for the brake disc 140. In this way, the hub flange 120 forms a shallow top-hat section. [0079] The brake disc 140 is an annular plate having a series of circumferentially spaced apart tab portions 145 that abut an outer surface 126.1 of the lip portion 126. As shown in Figure 2, the brake disc 140 is aligned with the hub flange 120 so that the mounting tab portions 145 of the disc 140 are aligned with mounting boss portions 128 of the hub flange 120 that are typically arranged about an exterior surface of the sidewall 124. Any suitable fasteners may then be used to fix the brake disc 140 to the hub flange 120 such that in use, the brake disc 140 rotates together with the hub flange 120.

[0080] As shown in Figure 2, it is to be appreciated that the lip portion 126 of the hub flange 120 includes spoke mounting holes 129 to which spokes of the wheel are attached during assembly. As both the spokes 40 and brake disc 140 are both attached to the lip portion 126 of the hub flange 120, it is to be appreciated that the brake disc 140 is therefore located substantially within the wheel and therefore out of the direct air flow path which provides an aerodynamic advantage compared to standard disc brake designs.

[0081] In the above-described arrangement, the brake disc 140 includes an inner peripheral edge 142 and an outer peripheral edge 144. The outer peripheral edge 144 is typically sharp and in standard disc brake systems is exposed therefore presenting a safety hazard to riders, in particular during a crash in which the disc may continue spinning and cause lacerations or burns to riders. In this arrangement, the outer edge 144 is at least partially shielded by the hub flange 120 as shown most clearly for example in Figure 2 and Figure 4.

[0082] As the diameter of the brake disc 140 is less than the diameter of the hub flange 120, the outer edge 144 is disposed within the boundary of the hub flange 120. In other words, the brake disc 140 does not extend radially beyond the hub flange 120 and as such the hub flange 120 acts as a shield or barrier preventing the outer edge 144 of the brake disc 140 from posing a hazard. In the example shown, the mounting tab portions 145 of the brake disc 140 abut the outer surface 126.1 of the lip portion 126 of the hub flange 120. Furthermore, the outer periphery 144 of the brake disc 140 has a diameter less than or equal to the inner diameter of the lip portion 126 in order to allow operation of the brake caliper 150 as shall be described below. Accordingly, in this example there is a step between the inner edge of the lip portion 126 and the outer edge 144 of the brake disc 140 equal to the thickness of the brake disc 140. The close proximity between the outer edge 144 of the brake disc 140 and the lip portion 126 of the hub flange 120 further provides a shielding effect and substantially reduces exposure of the outer edge 144 of the brake disc 140 leading to improved rider safety.

[0083] In other examples, the brake disc 140 may in fact be recessed within the sidewall portion 124 of the hub flange 120, however such a design would depend on spatial limitations imposed by the brake caliper.

[0084] In order for the hub flange 120 to shield the outer edge 144 of the brake disc 140 as described, the brake caliper 150 must be arranged in an opposite manner to standard calipers in which the caliper slides over the outer edge of the brake disc. In this arrangement, the brake caliper 150 slides over the inner periphery or edge 142 of the brake disc 140 and is fitted from the wheel centre radially outwards.

[0085] The brake caliper 150 includes a caliper mount 170 including a base which is an anti- rotation member 172 that is keyed, splined etc. to the wheel hub 110 proximate end 112. Any suitable form of engagement may be used such that the caliper mount 170 is rotationally fixed with respect to the hub 110. The caliper mount 170 further includes support arms 174 that project away from the base 172 and which are coupled to the caliper housing 152.

[0086] In this floating caliper example, each support arm 174 terminates in a support arm lug 176 having an aperture therethrough. The spaced apart support arm lugs 176 are disposed between corresponding pairs of caliper housing lugs 156, 158 which also have apertures that align with the support arm lug apertures. A pin member 180 is inserted through each pair of support arm and caliper housing lugs so that the caliper housing 150 is able to float laterally relative to the caliper mount 170 on said pins 180.

[0087] The caliper housing 152 is generally shaped like a horse-shoe having a first side portion 152.1 and a second side portion 152.2 that in use, are disposed about opposing sides of the brake disc 140. The first side portion 152.1 is disposed outside the brake disc proximate first braking surface 141 whilst the second side portion 152.2 is disposed inside the brake disc (and within a recessed portion 127 of the hub flange 120 defined by the sidewall portion 124) proximate second braking surface 143.

[0088] The first side portion 152.1 houses one or more hydraulic cylinders 160 that are operable to drive one or more pistons coupled to a first brake pad 162 towards braking surface 141 of the brake disc 140. A second brake pad 164 is housed within the second side portion 152.2 of the caliper housing 152 and in operation, when the one or more cylinders 160 are hydraulically actuated to apply a braking force to the brake disc 140, the caliper housing floats so as to align and centralise the caliper housing 152 around the brake disc 140 so that braking forces are balanced between brake pad 162 applying a force to braking surface 141 and brake pad 164 applying an equal and opposite force to braking surface 143.

[0089] A brake assembly 200 having an "opposing cylinder" caliper arrangement shall now be described in further detail with reference to Figures 5A, 5B, 6, 7 and 8.

[0090] Similar to the previously described example, the brake assembly 200 includes a wheel hub 210 having a cylindrical body or shell 211. The hub 210 includes a first flange 213 at a first end to which spokes 40' extending from the rim 20' of the bicycle wheel 10' are attached. Proximate a second end 212, the hub 210 includes a second flange 220 that radially projects away from the hub body 211. As shown in the figures, the second flange 220 defines a significantly larger diameter than the first flange 213. Typically, the ratio between the diameter of the second and first flanges is between, but not limited to, 2: 1 to 3 : 1.

[0091] In the example shown, the second flange 220 (referred to herein as the "hub flange") includes a radially projecting plate portion 222 which typically includes a series of cut-outs 223 such that the plate portion 222 defines a series of spaced apart arm or strut members 222.1 that extend away from the hub body 211 towards an outer edge 222.2 of the plate portion 222. A sidewall portion 224 (having a plurality of cut-outs) projects away from an outer edge 222.2 of the plate portion 222 in a direction of elongation of the hub body 211 and terminates in an out-turned lip portion 226 that provides a mating interface for the brake disc 240. In this way, the hub flange 220 forms a shallow top-hat section. [0092] The brake disc 240 is an annular plate having a series of circumferentially spaced apart tab portions 245 that abut an outer surface 226.1 of the lip portion 226. As shown in Figure 6, the brake disc 240 is aligned with the hub flange 220 so that the mounting tab portions 245 of the disc 240 are aligned with mounting boss portions 228 of the hub flange 220 that are typically arranged rearward of the lip portion 226. Any suitable fasteners may then be used to fix the brake disc 240 to the hub flange 220 such that in use, the brake disc 240 rotates together with the hub flange 220.

[0093] As shown in Figure 6, it is to be appreciated that the lip portion 226 of the hub flange 220 includes spoke mounting holes 229 to which spokes of the wheel are attached during assembly. As both the spokes 40' and brake disc 240 are both attached to the lip portion 226 of the hub flange 220, it is to be appreciated that the brake disc 240 is therefore located substantially within the wheel and therefore out of the direct air flow path which provides an aerodynamic advantage compared to standard disc brake designs.

[0094] In the above-described arrangement, the brake disc 240 includes an inner peripheral edge 242 and an outer peripheral edge 244. The outer peripheral edge 244 is typically sharp and in standard disc brake systems is exposed therefore presenting a safety hazard to riders, in particular during a crash in which the disc may continue spinning and causes lacerations or burns to riders. In this arrangement, the outer edge 244 is at least partially shielded by the hub flange 220 as shown most clearly for example in Figure 6 and Figure 8.

[0095] As the diameter of the brake disc 240 is less than the diameter of the hub flange 220, the outer edge 244 is disposed within the boundary of the hub flange 220. In other words, the brake disc 240 does not extend radially beyond the hub flange 220 and as such the hub flange 220 acts as a shield or barrier preventing the outer edge 244 of the brake disc 240 from posing a hazard. In the example shown, the mounting tab portions 245 of the brake disc 240 abut the outer surface 226.1 of the lip portion 226 of the hub flange 220. Furthermore, the outer periphery 244 of the brake disc 240 has a diameter less than the inner diameter of the lip portion 226 in order to allow operation of the brake caliper 250 as shall be described below. In particular, in this example, as the brake caliper 250 includes one or cylinders on the inside of the brake disc 140, the caliper housing 152 requires more space within the hub flange 220 and accordingly further spacing is required between the inner edge of the lip portion 226 and the outer edge 244 of the brake disc 240 to facilitate this type of caliper.

[0096] However, it is to be understood that in this arrangement the brake disc 240 extends axially proud of the outer surface 226.1 of the lip portion 226 by no more than a thickness of the brake disc 240. As such, the hub flange 220 still provides a shielding effect and substantially reduces exposure of the outer edge 244 of the brake disc 240 leading to improved rider safety.

[0097] In other examples, the brake disc 240 may in fact be recessed within the sidewall portion 224 of the hub flange 220, however such a design would depend on spatial limitations imposed by the brake caliper.

[0098] In order for the hub flange 220 to shield the outer edge 244 of the brake disc 240 as described, the brake caliper 250 must be arranged in an opposite manner to standard calipers in which the caliper slides over the outer edge or periphery of the brake disc. In this arrangement, the brake caliper 250 slides over the inner periphery 242 of the brake disc 240 and is fitted from the wheel centre radially outwards.

[0099] The brake caliper 250 includes a caliper mount 270 including a base which is an anti- rotation member 272 that is keyed, splined etc. to the wheel hub 210 proximate end 212. Any suitable form of engagement may be used such that the caliper mount 270 is rotationally fixed with respect to the hub 210. The caliper mount 270 further includes support arms 274 that project away from the base 272 and which are coupled to the caliper housing 252.

[0100] In this "opposing cylinder" caliper example, each support arm 274 terminates in a support arm lug 276 having an aperture therethrough. The spaced apart support arm lugs 276 are disposed in abutment with corresponding pairs of caliper housing lugs 256 which also have apertures that align with the support arm lug apertures. A fastener such as a bolt 280 is inserted through each pair of support arm and caliper housing lugs so that the caliper housing 250 is fixed relative to the caliper mount 270.

[0101] The caliper housing 252 is generally shaped like a horse-shoe having a first side portion 252.1 and a second side portion 252.2 that in use, are disposed about opposing sides of the brake disc 240. The first side portion 252.1 is disposed outside the brake disc 240 proximate first braking surface 241 whilst the second side portion 252.2 is disposed inside the brake disc (and within a recessed portion 227 of the hub flange 220 defined by the sidewall portion 224) proximate second braking surface 243.

[0102] The first side portion 252.1 houses one or more hydraulic cylinders 260.1 that are operable to drive one or more pistons coupled to a first brake pad 262 towards braking surface 241 of the brake disc 240. The second side portion 252.2 houses one or more opposing hydraulic cylinders 260.2 that are operable to drive one or more pistons coupled to a second brake pad 264 towards braking surface 243 of the brake disc 240. In this arrangement, the opposing cylinders are able to balance the braking forces applied to brake disc 240 such that no float is necessary in the caliper 250.

[0103] In the opposing cylinder caliper example, as the caliper housing 252 is required to house cylinders and pistons on opposing sides of the brake disc 240, the housing 252 is typically wider than the housing 152 for the floating caliper arrangement. As such, the hub flange 220 is typically deeper than the hub flange 120 which permits a more compact arrangement. For this reason, in order to reduce weight, the hub flange 220 may have more cut-outs. In both examples, the brake caliper is substantially out of the aerodynamic flow (at least partially concealed by the hub flange) and the brake disc is substantially within the wheel profile which also leads to an improvement in aerodynamic performance.

[0104] Accordingly, it will be appreciated that in at least one example the above described brake assemblies provide improvements in disc brake designs which significantly reduce existing risks associated with standard disc brakes. As the outer peripheral edges of the discs are shielded to eliminate or at least substantially reduce exposure thereof, the risks associated with accidental lacerations or burns are mitigated. The examples presented herein are therefore able to achieve improved safety and whilst not compromising braking performance and additionally providing a degree of aerodynamic benefit as a result of arranging the brake calipers out of the aerodynamic flow around the bicycle.

[0105] Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

[0106] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.