⚙ TORQUEHUB H14: Planetary Bicycle Gear Hub Exploded in 3D

About this simulation

How a 14-Speed Planetary Bicycle Hub Works: Interactive 3D Exploded Assembly

SEO title: 14-Speed Bicycle Hub Exploded View & Assembly Simulator | TORQUEHUB H14
Meta description: Explore 137 mechanical parts inside a fictional 14-speed bicycle hub. Disassemble planetary gears, operate a shifting mechanism, and rebuild the transmission in interactive 3D.
Suggested URL: /simulators/torquehub-h14-exploded-bicycle-hub/
Audience: Students, mechanics, cyclists, STEM educators, engineering visualisation enthusiasts.

Discover the hidden gearbox inside a bicycle wheel

Most bicycles change gears by moving the chain across different sprockets. An internally geared bicycle hub takes a different approach: several combinations of gears live inside the rear wheel hub itself. From the outside, the mechanism may look like a compact metal cylinder, but its interior includes precision gear wheels, bearings, pawls, clutch elements and a carefully indexed shift control. Understanding that arrangement from a flat illustration is challenging. TORQUEHUB H14 is an interactive exploded-view laboratory that lets you look at the mechanism from any angle, separate each component, study its role, and build the assembly back together.

The simulation contains 137 independently selectable mechanical components, arranged into seven educational subsystems. Its mechanism is a fictional, stylised 14-ratio compound planetary hub designed specifically for exploring engineering principles. It is not a dimensional replica of any commercial transmission; the ratios, dimensions, masses, engagement logic and materials are illustrative. The tooth-count relationships are grounded in elementary planetary gear geometry, while the simplified gear profiles and visible component motion make the underlying principles easier to observe. No specification should be used to fabricate a riding component.

The central idea: a compact planetary gear train

A simple planetary stage has a central sun gear, several smaller planet gears, a surrounding internally toothed ring gear, and a carrier supporting the planet pins. All four elements share a central axis, though the planets are positioned around it. A gear stage can transmit speed, change torque, or reverse relative motion when one of its members is held or driven. The particular behaviour depends on which element receives input, which element outputs motion, and which element reacts against the stationary frame.

For an ideal, rigid, simple planetary stage, angular velocities satisfy the Willis relation:

Nₛ ωₛ + Nᵣ ωᵣ = (Nₛ + Nᵣ) ω꜀

Here Nₛ and Nᵣ are sun and ring tooth counts, and ωₛ, ωᵣ, and ω꜀ are their respective angular velocities. This equation is useful because it describes a family of operating conditions rather than one fixed speed ratio. When the ring is stationary, the carrier and sun follow one relation; when the sun is stationary, another relation applies. Compound hub transmissions combine several such states to provide a wider selection of usable wheel speeds.

TORQUEHUB H14 visualises three stages with sun gears of 16, 20 and 24 teeth, planet pinions of 12 teeth, and internal rings of 40, 44 and 48 teeth. These counts satisfy the elementary same-module packaging relation Nᵣ = Nₛ + 2Nₚ, where Nₚ is the planet tooth count. Real tooth geometry also demands correct module, profile, backlash, centre distance, carrier construction and lubrication, which a teaching model does not validate.

Seven subsystems you can explore

1. Axle and bearings. The hardened central axle is the fixed reference for the assembly. Bearing seats, dust washers, locknuts, splines and races help show how rotating members can be supported while the axle remains attached to a bicycle frame. In the assembly challenge, the axle is the only initially installed part: everything else is built relative to that datum.

2. Planetary Stage A. The first stage introduces the sun, carrier, ring, four planet pinions, separate planet pins, needle bearings, thrust washers, pawls and carrier fasteners. This section provides a useful introduction to internal and external gear meshing. The gold-toned pinions are deliberately visible through the translucent housing.

3. Planetary Stage B. A second stage demonstrates why compound transmissions have more options than single-stage devices. A shift system can selectively couple members or establish reaction paths, creating a different effective ratio. Selecting the entire subsystem lets you isolate its pieces without losing their assembly positions.

4. Planetary Stage C. The final stage illustrates how multiple small mechanisms can be arranged along one axial line. Gear stages may share load paths and selector components. This laboratory deliberately simplifies real compound clutch tables, but it demonstrates that several independent stage states can contribute to one output.

5. Selector and clutches. The selector rod, dog-clutch sleeves, detent springs and indexing barrel represent the control mechanism that changes which gear members are engaged. The Operate mode moves the selector along its axis as the displayed gear number changes. In a real product, this subsystem also requires shift timing, positive engagement and careful prevention of incompatible simultaneous clutch states.

6. Freehub and chain input. A chain-driven sprocket rotates the input driver. Roller-clutch and ratchet components illustrate one-way coupling. The coasting control demonstrates the concept of a wheel turning without the rider continuing to pedal. The simulated pawls and rollers are instructional representations, not a validated clutch design.

7. Hub shell and seals. The exterior contains two removable shell sectors, spoke flanges, service bearings, seals and anchor bosses. The shell is translucent in the default viewer so the internal power path remains legible. Use X-Ray for a more transparent view of the internal train.

Why an exploded view is useful

A conventional product photograph hides the order in which parts fit together. An exploded view moves related components apart while preserving their identity and orientation. This makes fastening relationships, bearing placement, and mechanical clearances easier to understand. TORQUEHUB H14 offers five different explosion patterns, all driven by continuous, reversible transforms computed from the same original component positions.

Full explosion spreads components out along individual directions. Layered explosion emphasises axial order through the centre of the hub. Subsystem explosion moves only a selected mechanism, making it especially helpful for tracing one planetary stage. Technical explosion organises parts with interactive labels and relationship lines. Cinematic explosion varies separation timing for a carefully staggered presentation. In every mode, a slider from zero to one hundred percent lets you move smoothly between installed and separated layouts. Returning to zero restores the exact stored positions rather than incrementally accumulating transforms.

Building the hub back together

Exploration becomes a practical learning exercise when the object must be assembled rather than merely animated in reverse. In Assemble mode, every removable part is uninstalled and the central axle remains on the workbench. Select a component in the searchable tree. It appears near its target anchor, where you can translate it along the hub axis or across the radial plane. Rotate the part to align it with its socket, inspect dependency hints and attempt a magnetic snap.

The snap operation is a real rule check in the simulation. It verifies that all named prerequisite components are installed and that translation and angular offsets fall inside defined tolerances. The educational tolerances are 0.22 scene units and approximately 20 degrees; they are interface tolerances, not physical manufacturing clearances. A rejected snap explains the blocking dependency or misalignment. The Align Near button is an optional assist that brings a part close enough to practise the final operation; the selected piece is not magically installed until the Snap check succeeds.

In Free Assembly, any component whose dependencies are satisfied can be installed. Guided Assembly recommends the next eligible piece and enforces a suggested order. Challenge mode retains dependency and tolerance checks while recording mistakes. A progress meter shows how many of the 136 removable parts are installed and signals completion when every part returns to its required position.

Operating the illustrated gearbox

Switch to Operate and use the gear buttons to move between fourteen sample output ratios. The display reports the selected ratio relative to a nominal input rotation. The available values run from 0.279 to 1.467, with an illustrative direct-drive state of 1.000. Those exact ratios are not derived from a complete manufacturing-grade clutch truth table. Instead, they are a carefully labelled educational control series for observing how speed choices alter a moving gear train.

The simulation rotates the input driver and individual sun, ring, carrier and planet meshes. The planet components both revolve around a carrier axis and spin around their individual pins, visually demonstrating two distinct types of motion. Shaft rotation and indexing motion are deterministic functions of simulation time, selected gear and control state. A coasting toggle disconnects the simplified input movement from wheel-output motion. Adjust the pedalling rate or pause playback to inspect the relationship frame by frame.

The design deliberately avoids suggesting that every animated shaft has been verified against a full multi-stage constraint solver. For classroom use, compare the Willis equation with one isolated stage, then discuss what additional fixed members, couplings and losses a real fourteen-ratio drivetrain would require.

Materials, bearings and mechanical credibility

Many bicycle hubs use a combination of hardened steels, aluminium components, bearings, seals and lubricated gear interfaces. The laboratory distinguishes metals, darkened housings, copper-toned thrust surfaces, ceramic-coloured bearing parts and flexible seals with different colours and simulated surface properties. The Three.js source uses PBR metallic-roughness materials and multiple lights; the standalone distribution includes its own native WebGL2 lighting shader. Three exported GLB scenes retain named components and material assignments for independent inspection in compatible 3D software.

A real internal hub also needs tolerances, lubricant flow, gear tooth root strength, contact stresses, bearing life, thermal considerations and sealing against water. None of these is certified by this browser model. In particular, gear profiles are faceted procedural approximations rather than standards-compliant involute teeth. Its purpose is to explain the arrangement and movement of parts, not to serve as a parts catalogue or machine-shop blueprint.

Controls, camera views and accessibility

Drag to orbit around the gearbox and use the scroll wheel or pinch gesture to zoom. Shift-drag or a middle/right mouse drag pans the camera. Camera presets provide isometric, top, front, rear and side views, while Focus centres the selected part. The left assembly tree can be searched by component name, identifier or material. The right inspector provides each part's educational description, grouped system, visual material, approximate dimensions and dependency list.

You can hide an individual component, isolate a subsystem, and restore visibility at any time. Playback controls include Play/Pause, Replay, Reset and selectable animation speed. The viewport is designed for desktop and mobile layouts, with the tree and inspector stacking below the viewer on smaller screens. Actual frame rate varies by browser, graphics hardware, display size and number of visible components; the simulation does not guarantee a particular FPS.

Save locally and continue learning

The Save Local command stores the current assembly and interface state in browser localStorage. This includes selected mode, installed parts, the camera, explosion setting, shift position and learning progress. Load Local restores the saved snapshot on that browser and device. The scene also automatically saves changes to supported localStorage environments. No sign-in, remote server or API key is required for the shipped standalone viewer, although the site itself must be served over HTTP or HTTPS so its ES modules and component JSON can load properly.

Use the Mark Studied control to track inspected components. In a classroom, learners can work through one stage at a time, make a sketch of the expected torque path, validate the placement sequence, and then compare their explanation with the animated inspection. This turns a technical cutaway into an interactive spatial reasoning exercise.

Deployment on MySimulator.uk

Upload the contents of the dist/ directory as static files. Keep index.html, main.js, app.js, renderer.js, core.js, geometry.js, parts.json and style.css together. The default distribution uses browser-native WebGL2 and has a Canvas 2D fallback for environments where 3D acceleration is unavailable. An optional Three.js, TypeScript and Vite source project is also included for advanced rendering work and future production builds after dependencies can be installed.

With a single subject, a searchable part catalogue and meaningful assembly logic, TORQUEHUB H14 is suitable for interactive lessons about gear ratios, kinematic constraints, fastening relationships and mechanical packaging. Try the exploded animation first, inspect the planets and bearings next, then complete the assembly challenge to discover just how many smaller mechanisms cooperate inside an apparently simple wheel hub.

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