TECHNOLOGY ENABLING UTILIZATION OF WIRELESS GEAR SHIFTING CONTROLLERS WITH VIRTUAL SHIFTING PROVIDED VIA STATIONARY CYCLING TRAINER ASSEMBLIES

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of Australian Patent Application Serial No. 2024903831, filed Nov. 21, 2024, for “Technology Enabling Utilisation Of Existing Wireless Gear Shifting Controllers With Virtual Shifting Provided Via Stationary Cycling Trainer Assemblies.”

TECHNICAL FIELD

The present disclosure relates, in various embodiments, to technology enabling utilization of wireless gear shifting controllers (i.e. those which are by design configured to operate with a mechanical derailleur) with virtual shifting provided via with stationary cycling trainer. For example, some embodiments enable a user of a bicycle that has a wireless gear shifting components to transition between using their gear shifter component with a wireless derailleur and a virtual shifting system provided in the context of a stationary cycling trainer assembly. While embodiments will be described primarily in relation to such embodiments, it will be appreciated that the invention may have broader application.

BACKGROUND

Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.

It is known to provide virtual shifting functionality via a stationary cycling trainer assembly. For example, a bicycle having a derailleur/cassette arrangement is mounted (wheel off) to a stationary cycling trainer assembly that has a single speed cog (as opposed to a cassette). In such an arrangement, gear changes via the trainer assembly are virtual, in the sense that they are enabled (for example) via combination of control software and resistance control hardware provided in conjunction with the trainer. In some cases a physical controller is provided to allow a user to control such virtual gear shifting.

A problem can arise where a user inadvertently shifts gear via their bicycle's legacy gear shifters instead of the trainer's physical virtual shifting controller, and in doing so misaligns their derailleur/chain with respect to the single speed cog provided by the trainer assembly. An existing partial solution is to design a single speed cog that includes chain retention members to reduce the risk of such shifting resulting in chain drop/slip.

It is an object of the present disclosure to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

BRIEF SUMMARY

Example embodiments are described below in the section entitled “claims,” and in the section entitled “Detailed Description.”

Reference throughout this disclosure to “one embodiment,” “some embodiments,” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in some embodiments,” or “in an embodiment” in various places throughout this disclosure are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

As used herein, unless otherwise specified the use of the ordinal adjectives “first,” “second,” “third,” etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

In the claims below and the description herein, any one of the terms “comprising,” “comprised of,” or “which comprises” is an open term that means including at least the elements/features that follow, but not excluding others. Thus, the term “comprising,” when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression “a device comprising A and B” should not be limited to devices consisting only of elements A and B. Any one of the terms “including,” “which includes,” or “that includes” as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, “including” is synonymous with and means “comprising.”

As used herein, the term “exemplary” is used in the sense of providing examples, as opposed to indicating quality. That is, an “exemplary embodiment” is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 provides a diagram of a system according to one embodiment.

DETAILED DESCRIPTION

The present disclosure relates, in various embodiments, to technology enabling utilization of wireless gear shifting controllers (i.e. those which are by design configured to operate with a mechanical derailleur) with virtual shifting provided via with stationary cycling trainer. For example, some embodiments enable a user of a bicycle that has a wireless gear shifting components to transition between using their gear shifter component with a wireless derailleur and a virtual shifting system provided in the context of a stationary cycling trainer assembly. While embodiments will be described primarily in relation to such embodiments, it will be appreciated that the invention may have broader application.

Various embodiments described below are applicable in the context of stationary cycling trainers (“trainers”) known as “wheel-off” trainers. These are configured to receive a partially deconstructed bicycle, deconstructed in the sense that the rear wheel is removed. The bicycle is them mounted to the trainer, and the bicycle's chain coupled to a cassette or cog provided by the trainer. The trainer offers variable resistance to pedaling, for example, based on control via software (which may receive resistance controlling instructions from ride simulation software such as Zwift or MyWhoosh, noting that no approval or affiliation is suggested by use of these brand names).

Some known examples of trainers and/or simulation software provide what is referred to as “virtual shifting.” This refers to an arrangement whereby the trainer is controlled to provide a simulation of gear shifting, as opposed to conventional arrangements where the trainer provides a cassette for physical gear shifting via aa shifter/derailleur arrangement provided by the bicycle. In some such cases, the trainer includes a single speed cog (or other arrangement incompatible with physical gear shifting via the bicycle's existing gear shifter component).

The present disclosure provides a control system for a cycling trainer assembly, wherein the trainer assembly is configured to provide such virtual shifting function (and wherein the trainer assembly is configured to be used with a partially deconstructed conventional bicycle as descried above). The control system includes: (i) an input for receiving a wireless control signal from a gear shifter component provided by the bicycle; and (ii) a component configured to process the control signal and in response trigger functionality that results in a virtual gear shifting operation by the cycling trainer assembly.

By way of example, the gear shifter component provided by the bicycle may be a SRAM AXS (or compatible) gear shifter component, or a Shimano Di2 (or compatible) gear shifter component. These are examples only, and it will be appreciated that embodiments may operate with these and other (including future) wireless gear shifter arrangements. These may operate based on wireless protocols including the likes of Bluetooth, Bluetooth LE, ANT and/or other protocols (including future developed protocols). It will be appreciated by those skilled in the relevant art how embodiment may be adapted to operate with a wide range of gear shifter technologies and communications protocols.

For the purpose of embodiment described below, it is generally assumed that the gear shifter component is, during normal use of the bicycle without the trainer assembly, configured to wirelessly control a component of the bicycle, specifically being a derailleur. However, in alternate embodiments, the gear shifter component may be another form of component, for example, a dropper post controller or the like. That being said, the use of a gear shifter component that in normal cycling operation controls the bicycle's derailleur is preferable, on the basis that it enables virtual gear shifting during trainer user to be achieved via the same user input as physical gear shifting during conventional cycling.

The control system may be provided via any one or more: (i) trainer assembly; (ii) software that enables control of a trainer assembly; (iii) a gear shifter component that is configured to enable wireless gear shifting via the bicycle; and embedded software (including firmware) provided via a gear shifter component that is configured to enable wireless gear shifting via the bicycle.

FIG. 1 illustrates an example embodiment. A bicycle includes a wireless gear shifter 100 and a wireless derailleur 101, which is adapted to work with shifter 100 to enable physical gear changes during normal cycling operation. A cycling trainer arrangement 110 includes trainer assembly hardware/software 111 and optionally ride simulation hardware/software 112 (for example, a device such as a mobile device, gaming device, streaming device or other smart device that executes software such as Zwift or MyWhoosh). Shifter 100 is able to communicate with wireless derailleur 101 during normal cycling operation for the purposes of controlling physical gear shifting, and also able to communicate (although preferably not concurrently) with trainer arrangement 110 during trainer operation for the purposes of controlling virtual gear shifting during use of the trainer assembly.

In some embodiments, the technology is configured to transition between cycling operation and trainer operation based on a user input. In other embodiments, a prioritization protocol is implemented via one or more of the components shown in FIG. 1 thereby to manage transition between cycling operation and trainer operation. For example, in some embodiments, during cycling operation the shifter pairs with (or otherwise links with for the purpose of control) the derailleur, whereas during trainer operation, the shifter pairs with (or otherwise links with for the purpose of control) the trainer assembly (or optionally the ride simulation hardware/software).

The prioritization protocol preferably causes the gear shifter to pair with the control system in preference to the derailleur when predefined trainer connection conditions are met (or pair with the derailleur in preference to the control system when predefined trainer disconnection conditions are met). The predefined trainer connection conditions include any one or more of the following:

• • the trainer assembly is in an active state;
  • the trainer assembly is in a pairing mode;
  • software associated with the trainer assembly is in an active state;
  • software associated with the trainer assembly is in a pairing mode active state; or
  • a predefined command is provided via a user.

The predefined trainer disconnection conditions include any one or more of the following:

• • the gear shifter is unable to identify connect to the control system;
  • the trainer assembly is in an inactive mode;
  • software associated with the trainer assembly is in an inactive mode;
  • a predefined command is provided via a user.

In this regard, any one or more of the following use cases may be implemented:

• • The gear shifter connects to whichever of the trainer or the derailleur is switched on.
  • If both the gear shifter and the derailleur is switched on and within range, the gear shifter connects to the trainer.
  • Upon losing connection to the trainer, the gear shifter seeks to connect to the derailleur.

The prioritization protocol may be implemented via embedded firmware/software of the shifter, the trainer hardware/software, the ride simulation hardware/software and/or other components. Ultimately, preferably this is configured in a manner that streamlines transition between cycling and trainer modes, and reduces the risk of effecting derailleur control when the trainer is being used.

In some embodiments, existing technology platforms (for example, those made available by Shimano and SRAM) are modified to enable use of their shifters with a trainer device. Examples are provided below. Nothing should be read to suggest approval from SRAM or Shimano in the context of this disclosure.

Electronic wireless shifting systems for bicycles are well known. Shimano and SRAM each provide commercially available wireless or semi-wireless groupsets in which handlebar-mounted shifters communicate with one or more derailleurs by means of proprietary, encrypted radio protocols. In Shimano systems, the rear derailleur typically acts as a central controller that manages wireless links to the shifters and wired links to other drivetrain components. In SRAM AXS systems, shifters typically transmit commands directly over a decentralized wireless mesh to one or more derailleurs or other AXS components.

Indoor smart trainers, such as the JetBlack Victory, Wahoo KICKR trainer family, and comparable devices, provide electronically controlled resistance and may support “virtual gearing,” in which a trainer simulates changes in gear ratio without requiring a physical shift in the bicycle's mechanical drivetrain. In existing systems, virtual gearing is usually controlled either by software applications running on a computing device (for example, a laptop or smartphone) or by a dedicated auxiliary controller. A rider who uses an electronic groupset outdoors and a smart trainer indoors typically must either: (a) use different controls for indoor virtual gear changes and outdoor mechanical shifting; or (b) manually re-pair or reconfigure their shifter for different operating contexts.

This separation of control paradigms leads to inconvenience and a discontinuity in user experience. Riders would benefit from being able to use the same wireless shifters (for example, Shimano Di2 wireless shifters or SRAM AXS wireless shifters) both to actuate the physical derailleur while riding outdoors, and to actuate virtual gearing of an indoor trainer while the bicycle is mounted to the trainer and the trainer is active. A naïve approach in which the same shifter simply transmits commands to both trainer and derailleur simultaneously, however, would result in simultaneous control of both virtual and physical gears. When the rear wheel is fixed in a trainer, unintended physical gear changes may be undesirable or mechanically problematic.

According to one aspect of the present disclosure, there is provided a method of operating an electronic bicycle shifting system that includes a wireless shifter and a physical derailleur, and an indoor trainer capable of receiving gear shift commands. The method comprises:

• • (a) operating the shifter in a normal mode in which shift commands generated by the shifter are communicated to the derailleur and cause mechanical gear shifting;
  • (b) detecting activation of a known indoor trainer associated with the shifter;
  • (c) in response to detecting trainer activation, entering a trainer mode in which subsequent shift commands generated by the shifter are communicated to the trainer as virtual gear shift commands and are not acted upon by the derailleur; and
  • (d) detecting deactivation or absence of the trainer and, in response, reverting from the trainer mode to the normal mode such that subsequent shift commands again actuate the derailleur.
  • In preferred embodiments, the method is implemented by suitable modifications to firmware executing on existing commercial wireless shifters and associated drivetrain components. The invention is described in separate embodiments for Shimano-type systems, in which a rear derailleur or other central controller manages the wireless network, and SRAM-type systems, in which shifters directly transmit commands in a decentralized AXS network. In each case, one or more indoor trainer activation-detection mechanisms, mode-switching algorithms, and fail-safe behaviors are provided so that the shift commands are directed exclusively to one control target (the derailleur or the trainer) at a given time.

In further aspects, the present disclosure contemplates multiple alternative implementations of trainer detection and mode switching, including: (i) beacon-based detection in which the trainer broadcasts an activation signal; (ii) device-initiated handshakes in which the trainer explicitly requests control; (iii) host-orchestrated switching via an intermediate head unit or computing device; and (iv) local state-based logic incorporating wheel speed, cadence, accelerometer data, or power-sensor information to confirm an indoor training context.

Generic Architecture and Operating Modes

In a generic embodiment, a system according to the present disclosure comprises:

• • (1) At least one wireless shifter mounted at or near a bicycle handlebar;
  • (2) At least one electronically actuated derailleur, such as a rear derailleur, capable of receiving wireless or wired shift commands from the shifter directly or via a central controller;
  • (3) An indoor smart trainer capable of receiving gear-related control messages and implementing virtual changes in resistance or simulated gear ratio; and
  • (4) One or more communication links, which may include proprietary low-latency radio links, ANT+ links, Bluetooth Low Energy (BLE) links, or manufacturer-specific links between the shifter, derailleur and trainer.

The system operates in at least two logical modes:

• • (a) A “normal” or “derailleur” mode in which shift commands emitted by the shifter cause mechanical gear shifts through movement of the derailleur; and
  • (b) A “trainer” mode in which shift commands emitted by the shifter are translated into virtual gear shift commands delivered to the trainer and do not cause mechanical derailleur movement.

The system transitions between these modes based on the detection of activation or deactivation of a known trainer associated with the shifter.

Shimano-Type System Embodiments

Shimano wireless groupsets, such as those in the Dura-Ace R9200, Ultegra R8100 and 105 Di2 R7100 series, employ a hybrid architecture in which the shifters communicate wirelessly with a rear derailleur that acts as a central controller. The rear derailleur is typically connected by wired links to a battery and to a front derailleur, and manages system state, configuration, and routing of shift commands. Wireless messages from the shifters are received by the rear derailleur, which then directly actuates itself and/or issues wired commands to the front derailleur.

In a first Shimano-type embodiment of the present disclosure, the firmware of the rear derailleur is modified to implement multi-target control and trainer-aware routing, while the firmware of the shifters is minimally extended to support state reporting and optional trainer-specific communication profiles.

Alternative 1: Rear Derailleur-Centric Trainer Detection and Routing

In this alternative, the rear derailleur is responsible for detecting the presence of a compatible trainer and determining whether the system should be in normal mode or trainer mode. The shifters continue to send wireless shift messages to the rear derailleur using largely unmodified message formats.

Firmware modifications for the rear derailleur include at least the following elements:

• • (1) A trainer profile store, in which one or more trainer identifiers (TrainerIDs) and associated authentication or pairing data are stored in non-volatile memory. The trainer profile store may be configured via an external configuration application, such as an updated version of the manufacturer's configuration software.
  • (2) A trainer detection module, executed by a microcontroller of the rear derailleur, which periodically listens for trainer activation signals. In one implementation, the trainer broadcasts a beacon using a radio protocol compatible with the groupset's wireless transceiver. The beacon contains at least a TrainerID that can be matched against the trainer profile store, and may include version or capability information.
  • (3) A mode state machine implementing at least two states: a derailleur mode state and a trainer mode state. State transitions are triggered by detection or loss of trainer activation, with optional hysteresis or timeout parameters to avoid oscillation.
  • (4) A routing module that, in derailleur mode, interprets incoming shift messages as commands to actuate the rear derailleur (and, as appropriate, the front derailleur) and that, in trainer mode, suppresses physical actuation and instead generates trainer control messages based on the same incoming shift messages.

In use, when the trainer is inactive or absent, the rear derailleur resides in the derailleur mode state. Shift messages received from the shifters are processed according to existing Di2 logic and result in mechanical movement of the derailleur(s). When the trainer detection module detects a valid activation beacon corresponding to a known TrainerID, and optional corroborating signals (for example, an indication that the rear wheel speed is zero or that the bicycle has not experienced acceleration consistent with road riding), the mode state machine transitions into the trainer mode state. In the trainer mode state, the routing module does not energize the derailleur motors in response to incoming shift messages. Instead, it constructs and transmits virtual gear shift commands to the trainer. These commands may be sent via a proprietary protocol, a modified ANT+FE-C profile, or another wireless control channel supported by the rear derailleur's radio hardware.

Transition back to derailleur mode occurs when the trainer detection module determines that the trainer is no longer active. This may be based on the absence of trainer beacons for a predetermined timeout period, receipt of an explicit deactivation message from the trainer, a reduction in signal strength below a threshold, or any combination of such factors. When a transition to derailleur mode occurs, the rear derailleur resumes interpreting incoming shift messages as commands for mechanical actuation.

Alternative 2: Shifter-Centric Trainer Detection and Mode Switching

In a second Shimano-type alternative, the primary trainer detection and mode selection logic resides in the shifters themselves. Each wireless shifter is updated to maintain multiple communication profiles, including a profile for normal communication with the rear derailleur and one or more profiles for direct communication with a trainer.

The shifter firmware is extended to store a BikeID profile for the rear derailleur and a TrainerID profile for the trainer. The shifter periodically scans for trainer activation beacons. When a known trainer is detected, the shifter's internal state machine transitions from a derailleur profile to a trainer profile. In the trainer profile, the shifter's radio is configured to send shift messages directly to the trainer. Under this arrangement, the rear derailleur may be left unmodified, or may optionally be configured to ignore shift messages while trainer mode is active.

To prevent unintended mechanical shifting while the shifter controls the trainer, the shifter may either cease sending any messages using the BikeID profile during trainer mode, or may send a specific “control transferred” message to the rear derailleur instructing it to suspend motor actuation until control is restored. When the trainer beacons cease or a timeout is reached, the shifter reverts to the BikeID profile and resumes sending normal shift commands to the rear derailleur.

Alternative 3: Head Unit or External Device-Orchestrated Switching

A third Shimano-type alternative uses an external head unit or computing device, such as a cycling computer or smartphone application, as an orchestrator of control switching. In this embodiment, the head unit maintains connections to both the rear derailleur (or its controller) and the trainer, and receives shift event data from the shifters. The head unit then selects whether to route the shift events to the derailleur or the trainer based on trainer activation state.

The shifters in this embodiment may transmit shift events as data messages rather than direct actuation commands. The head unit receives these data messages and, when the trainer is inactive, translates them into commands sent to the rear derailleur. When the trainer is active, the head unit instead translates the data messages into virtual gear commands sent to the trainer. The rear derailleur may optionally receive a control suspension signal from the head unit or may simply fail to receive any commands while trainer mode is active.

Initial Pairing Procedures—Shimano-Type Systems

In Shimano-type embodiments of the present disclosure, initial pairing of the smart trainer to the bicycle system is performed so that the rear derailleur or the shifters (depending on which embodiment is used for mode detection and routing) recognize the trainer as an authorized device capable of receiving virtual shift commands. The pairing process establishes secure association, authentication credentials, and corresponding TrainerID profiles.

Alternative 1: Rear Derailleur-Centric Pairing Procedure

In this alternative, the initial pairing occurs between the smart trainer and the rear derailleur, which holds the trainer profile and performs trainer detection.

The process includes the following steps:

• • (1) The rear derailleur is placed into a pairing mode via a physical button press, software command, or sequence of shifter inputs. In pairing mode, the derailleur transceiver listens for pairing frames.
  • (2) The trainer is placed into pairing mode, during which it broadcasts pairing advertisements containing a temporary pairing token and a permanent trainer identifier (TrainerID).
  • (3) The rear derailleur receives the trainer's pairing token and responds with a cryptographic challenge using Shimano's proprietary wireless protocol.
  • (4) Upon successful response from the trainer, the derailleur stores the TrainerID and associated secure keys in non-volatile memory.
  • (5) The derailleur exits pairing mode and acknowledges successful trainer registration via an LED pattern or via an application interface.

In subsequent use, the derailleur uses the stored TrainerID to validate activation beacons emitted by the trainer.

Alternative 2: Shifter-Centric Pairing Procedure

In the shifter-centric Shimano embodiment, the shifters themselves store both BikeID and TrainerID profiles and perform the initial pairing with the trainer.

The pairing steps are as follows:

• • (1) The shifter is placed into pairing mode, either via a hardware input or via the manufacturer's configuration software. In this mode, the shifter advertises its availability for control association.
  • (2) The trainer transmits pairing advertisements. The shifter selects an advertisement that matches protocol requirements and then initiates a secure session key exchange with the trainer.
  • (3) The shifter stores a TrainerID profile containing trainer capabilities, authentication data and protocol versions.
  • (4) Optionally, the shifter transmits a “trainer pairing complete” message to the rear derailleur so that the derailleur can update its internal state and recognize the trainer when trainer mode is entered.
  • Following initial pairing, the shifter may automatically switch between TrainerID and BikeID when trainer activation is detected.

Alternative 3: Head Unit-Mediated Pairing

In the head-unit-centric embodiment, initial pairing is orchestrated by a head unit or application that maintains profiles for the derailleur system and the trainer.

The pairing process includes:

• • (1) The head unit scans for both the bicycle drivetrain controller (rear derailleur or central node) and the trainer.
  • (2) When both are detected, the head unit establishes secure connections, negotiates pairing tokens, and stores trainer information in a configuration profile.
  • (3) The head unit may push a configuration message to the shifters and/or derailleurs indicating that a trainer has been paired and providing a TrainerID profile.

SRAM-Type System Embodiments

SRAM AXS systems employ a decentralized architecture in which shifters typically send encrypted wireless commands directly to one or more derailleurs or other AXS components. There is no dedicated central controller analogous to the Shimano rear derailleur hub; instead, each AXS component participates in a wireless network using an AXS device identifier and shared encryption material.

In SRAM-type embodiments of the present disclosure, the shifters are modified to maintain multiple authenticated profiles corresponding to both the physical derailleur system and one or more indoor trainers, and to dynamically select which profile is active. The derailleurs may also be modified to recognize and respond to a control transfer signal that places them in a non-responsive state while trainer mode is active.

Alternative 1: Shifter-Driven Multi-Profile Routing

In a first SRAM-type alternative, each AXS shifter maintains a profile store that includes at least a BikeID profile for a derailleur set and a TrainerID profile for a compatible trainer. The profiles include device identifiers, session keys and radio configuration parameters. The shifter's firmware implements a mode state machine analogous to the generic operating modes described earlier.

In derailleur mode, the shifter configures its radio transceiver using the BikeID profile and transmits shift commands in the same manner as in conventional AXS systems. When the trainer is powered on and begins transmitting a trainer activation beacon bearing a recognized TrainerID, the shifter's trainer detection module determines that a trainer is present. Upon such detection, the mode state machine transitions into trainer mode.

In trainer mode, the shifter reconfigures its active communication profile from BikeID to TrainerID. Subsequent shift events are encoded as virtual gear increment/decrement commands and transmitted to the trainer. To prevent the derailleurs from also acting on legacy commands, the shifter either ceases any transmissions targeting the BikeID profile or sends a specific control suspension packet to the derailleurs before entering trainer mode.

When the trainer becomes inactive, as indicated by loss of trainer beacons, an explicit shutdown message, or a timeout condition, the shifter reverts to the BikeID profile and resumes standard transmissions to the derailleurs. The derailleurs may additionally interpret a control restoration packet to resume normal operation.

Alternative 2: Derailleur-Side Suppression of Mechanical Shifts

In a second SRAM-type alternative, the shifters may continue transmitting commands to the derailleurs in both modes, while the derailleurs themselves become trainer-aware and suppress mechanical actuation during trainer mode. In this arrangement, the trainer detection and mode state machine may be implemented in one of the derailleurs, for example, the rear derailleur.

The rear derailleur is modified to store one or more TrainerIDs and to listen for trainer activation beacons. When such a beacon is detected and validated, the derailleur enters a trainer mode in which it ignores or acknowledges but does not mechanically execute incoming shift commands. The derailleur may also initiate a separate communication session with the trainer to relay a representation of the incoming shift commands as virtual gear commands, or such relay may be performed by a head unit or other device that subscribes to the same shift events.

Alternative 3: Intermediate Device-Orchestrated Control for AXS

In a third SRAM-type alternative, an intermediate device such as a cycling head unit, smartphone, or dedicated bridge receives shift event data from the AXS shifters and, based on trainer activation state, forwards appropriate commands either to the derailleurs or to the trainer. The AXS shifters may in this case be configured to broadcast shift events as data packets to the intermediate device rather than sending direct actuation commands to the derailleurs. The intermediate device determines trainer presence by monitoring a connection with the trainer, and selectively routes the shift events accordingly.

To avoid conflicting control, the intermediate device can send a control suspension or control restoration signal to the derailleurs, or alternatively the derailleurs can simply act only upon direct AXS commands and ignore higher-level data messages used exclusively for trainer control.

Initial Pairing Procedures—SRAM-Type Systems

In SRAM AXS-type embodiments, initial pairing is achieved by enabling the AXS shifter to store a multi-device profile list that includes both a BikeID (the derailleur system) and one or more TrainerIDs (indoor trainers). Because the AXS system uses a decentralized architecture with shifter-initiated shift commands, initial pairing is performed primarily at the shifter level.

Alternative 1: Shifter-Centric Pairing Procedure

In the primary SRAM-type pairing embodiment, the shifter stores multi-target profiles and performs the pairing procedure with the trainer.

The procedure includes:

• • (1) The shifter is placed into AXS pairing mode (commonly invoked by pressing a component pairing button). The shifter begins broadcasting a pairing beacon.
  • (2) The trainer is placed into pairing mode and sends pairing advertisements compatible with the modified AXS trainer protocol.
  • (3) The shifter selects the trainer advertisement and initiates a session key exchange following SRAM's AXS encryption framework.
  • (4) A secure TrainerID profile is stored in the shifter's memory, including trainer capabilities and virtual gear mapping information.
  • (5) Optionally, a control-suspension notification is sent to the derailleurs indicating that trainer mode may be entered when activation occurs.

Alternative 2: Derailleur-Enhanced Pairing Procedure

• • In alternative SRAM embodiments that rely on derailleur-side suppression logic, the rear derailleur is also paired with the trainer to allow it to correctly recognize when to suppress mechanical shifts.

The process includes:

• • (1) The rear derailleur enters a modified pairing state in which it listens for trainer pairing advertisements.
  • (2) The trainer transmits a pairing advertisement containing a temporary key and static TrainerID.
  • (3) The derailleur validates the trainer, stores the TrainerID, and enters a ready state for trainer-aware operation.
  • (4) The derailleur may send an acknowledgement to the shifters via the AXS mesh, indicating that trainer pairing is complete

Alternative 3: Head Unit or Bridge Device-Orchestrated Pairing

• • In this alternative, pairing is mediated by a third-party device (head unit, smartphone, or dedicated AXS bridge). The shifters broadcast shift events, while the mediating device maintains pairing with both the trainer and the derailleur system.

The pairing flow includes:

• • (1) The head unit scans for and detects both AXS drivetrain components and trainer broadcasts.
  • (2) The head unit establishes session keys with each and creates TrainerID and BikeID profiles.
  • (3) The head unit optionally distributes trainer pairing information to the shifters so that they may locally detect trainer presence.

Common Safety and Fail-Safe Considerations

In all of the Shimano-type and SRAM-type embodiments described, common safety and fail-safe mechanisms are preferably implemented. These may include: enforcing mutual exclusivity of control such that at no time do the derailleur and trainer simultaneously act on the same shift commands; timeouts and automatic reversion to derailleur mode if trainer communication is lost; verification codes or session keys to ensure that only known trainers can request control; and hysteresis in state transitions to prevent rapid mode toggling in marginal signal conditions. Additionally, the user interface in associated configuration applications may provide the ability to enable or disable trainer mode, to select which trainer devices are recognized, and to set thresholds for trainer detection and timeout.

The described embodiments illustrate how existing Shimano and SRAM wireless shifting components may be modified at firmware and protocol levels to permit virtual gear shifting via an indoor trainer while preventing undesired mechanical gear shifting of a physical derailleur, and how seamless transitions between these two operating modes can be achieved without manual re-pairing or complex user interaction.

Further Embodiments: Manual Intervention

In some embodiments, the approaches above may be modified to facilitate implementations where a shifter is manually controlled to transition between the “normal” mode and the “trainer” mode, for example, making use of a predefined button operation on the shifter device (e.g., a long hold of one or more buttons, a sequence of button presses or the like).

Further Embodiments: Use of Auxiliary Buttons

In some embodiments, the approaches above may be modified to facilitate implementations where a shifter has: (i) gear shift buttons; and (ii) auxiliary buttons; and the technology is configured such that the auxiliary buttons are used to facilitate virtual gear shifting for the trainer (as opposed to dual-purposing the gear shift buttons).

Conclusions

The above disclosure provides valuable technologies to assist with the use of wireless shifters (e.g., Shimano and SRAM) with indoor trainer devices. It should be appreciated that embodiments may include:

• • Shifter and other components that have been modified to operate as described above;
  • Firmware for shifter and other components that have been modified to operate as described above;
  • Methods for modifying shifter and other components that have been to operate as described above;
  • Trainer devices configured to operate with shifter and other components that have been modified to operate as described above; and
  • Trainer device firmware and/or software (including external simulation software) configured to operate with shifter and other components that have been modified to operate as described above.
  • It should further be appreciated that in the above description of exemplary embodiments of the present disclosure, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this disclosure, with each claim standing on its own as a separate embodiment of this disclosure.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this disclosure.

Thus, while there has been described what are believed to be the preferred embodiments of the present disclosure, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present disclosure.