Design Intent
Axlow V1 should feel stable, low, comfortable, and precise. The first build should avoid unnecessary complexity and focus on a chassis that can be fabricated, adjusted, tested, and improved.
The design should be suitable for SolidWorks refinement, jig planning, and review by experienced fabricators before cutting metal.
- Low recumbent seating with real back support
- Two front steering wheels and one rear driven wheel
- Side steering handles with natural hand position
- Front crank boom with adjustment
- Rear chain drive for the first prototype
- Dual front disc brakes
- Mounting points for lighting, reflectors, flag, and future accessories
- Frame designed around local fabrication and repeatability
Preliminary Geometry
These are concept targets for CAD review. They should be tested against rider fit, turning radius, pedal clearance, ground clearance, and transport/storage constraints.
| Parameter | Concept Target | Review Notes |
|---|---|---|
| Overall length | 1850-2050 mm | Depends on boom adjustment and rear wheel size |
| Overall width | 820-880 mm | Should remain manageable for gates, storage, and transport |
| Front track width | 760-820 mm center-to-center | Wider improves stability but increases bulk |
| Wheelbase | 1200-1350 mm | Front axle line to rear axle |
| Seat base height | 300-380 mm | Lower is stable; too low may hurt entry/exit |
| Seat back angle | 42-50 degrees from ground | Adjustable preferred for rider comfort |
| Bottom bracket height | 430-520 mm | Slightly above seat base for recumbent pedaling |
| Ground clearance | 120-150 mm | Must handle uneven Indian surfaces |
| Front wheels | 20 inch | Common tadpole trike size and easier packaging |
| Rear wheel | 26 inch preferred, 20 inch alternate | 26 inch improves rollout; 20 inch keeps package compact |
| Boom adjustment | 180-250 mm | Final range depends on rider fit targets |
| Turning circle | Under 5 m target | Needs physical validation |
| Rider capacity | 100-120 kg | To be validated structurally |
| Prototype weight | 30-38 kg | Acceptable for mild steel Prototype 0, reduce later |
Frame Architecture
The frame should be simple enough for Prototype 0 while leaving clean paths for refinement. Every bracket should have a reason: fit, steering, chain management, lighting, safety, or serviceability.
- Main spine tube from boom receiver toward rear wheel structure
- Front cross-member carrying steering assemblies
- Rear fork or rear triangle supporting the driven wheel
- Seat base supports tied into the main spine
- Seat back supports tied into the rear frame
- Telescoping boom receiver with clamp and anti-rotation feature
- Gussets at front cross-member, seat mounts, and steering load points
- Idler bracket near the front/seat transition
- Welded tabs for brake cables, chain guards, lights, and reflectors
Steering Concept
The steering should be predictable before it is sporty. Side steering with link rods, adjustable rod ends, and modeled Ackermann geometry is the recommended starting point.
| Parameter | Concept Target | Why It Matters |
|---|---|---|
| Caster | 8-12 degrees | Self-centering and straight-line confidence |
| Camber | 0 to -2 degrees | Contact patch and cornering behavior |
| Toe-in | 1-3 mm total | Tracking stability and tire scrub control |
| Steering lock | Limited mechanically | Prevents heel, wheel, and linkage interference |
| Rod ends | Threaded adjustment | Allows tuning after fabrication |
Drivetrain Direction
The first prototype should use a chain drive because it is serviceable, available, and easy to test. Belt drive, custom gearing, or internal hubs may be attractive later, but they should not slow down Prototype 0.
- Standard bicycle crankset mounted on the adjustable front boom
- 1x8, 1x9, or 3x7 bought-out drivetrain for first testing
- Long chain routed along the main spine to the rear wheel
- Power-side idler near the front/seat transition
- Return chain through low-friction chain tube or protected guide
- Rear derailleur and cassette/freewheel
- Chain guards near rider hands, seat edge, clothing contact zones, and return path
Braking, Lighting, And Safety
- Dual front mechanical disc brakes as the Prototype 0 baseline
- Linked vs independent brake lever setup to be tested
- Rear parking brake if simple to add
- Brake cable routing clear of steering movement
- Headlamp and rear brake lamp mounts built into the design direction
- Side reflectors or side marker lights for low-slung visibility
- Flag mount for early testing and controlled-road visibility
- Mechanical steering stops and heel-clearance checks
- Chain guards wherever clothing, skin, or bags may contact the drivetrain
Prototype Test Plan
| Test Area | What To Check |
|---|---|
| Static alignment | Frame straightness, front toe, wheel tracking, seat mount flex |
| Steering | Lock-to-lock movement, interference, turning radius, self-centering feel |
| Braking | Straight stops, one-side braking behavior, lever reach, cable motion |
| Drivetrain | Chain line, idler noise, return path rubbing, derailment risk |
| Fit | Boom range, seat angle, entry/exit, knee and heel clearance |
| Ride comfort | Seat pressure, lower back support, vibration, road feel |
| Serviceability | Access to wheels, brakes, chain, idlers, and fasteners |
Key Risks
| Risk | Why It Matters | Early Mitigation |
|---|---|---|
| Poor steering geometry | Tire scrub, instability, unsafe handling | Model Ackermann and add toe adjustment |
| Brake imbalance | Trike may pull during braking | Test linked and independent braking |
| Chain routing complexity | Noise, derailment, and rider contact | Use idlers, chain tubes, and guards |
| Seat discomfort | The product fails if the ride is not comfortable | Prototype seat angle and support early |
| Excess weight | Harder to move, transport, and sell | Accept in V0, reduce after geometry is proven |
| Low visibility | Low vehicles need deliberate road presence | Design lighting and flag mounts from the start |
| Cost creep | Harder to commercialize | Buy standard parts first and manufacture only defining parts |