How to Assemble the Sixthreezero Relaxed Body Recumbent Electric Trike: A Complete Step-by-Step Guide

Unboxing a new electric trike is one of those moments that mixes excitement with a small wave of uncertainty. The box is large, the parts look numerous, and the prospect of getting everything right feels daunting — especially when the goal is to ride safely and confidently. The good news: the Sixthreezero Relaxed Body Recumbent Electric Trike is designed with the end user in mind, and the assembly process is far more approachable than it first appears.

This guide walks you through every stage of assembly from the moment the box lands on your doorstep to the first press of the power button. Whether you’re setting it up for yourself, a parent, or a partner, follow each section in order and you’ll have a fully operational trike ready for the road in a single afternoon.

What to Expect When Your Trike Arrives

The shipping box for the Relaxed Body Recumbent E-Trike is substantial — approximately 69 inches long, 34 inches wide, and 25 inches tall, with a total weight of around 100 pounds. Given those dimensions, it helps to be present at the time of delivery so the carrier can place it exactly where you want it. If that’s not possible, the box does have carry handles that allow you to drag or reposition it once it arrives.

The box is double-walled for added protection during transit — a detail that matters when you’re shipping something as large and precision-built as an electric trike. Once you start opening it, you’ll see that much of the trike arrives pre-assembled. The frame, rear axle, drivetrain, and braking system are already put together at the factory; what remains for home assembly is primarily the front wheel, handlebars, seat adjustment, fenders, basket, and battery installation.

Before you cut a single zip tie, identify a clean, flat workspace with enough room to maneuver around the trike. A garage floor or driveway works well. Lay down the inner box flaps as a temporary surface to protect any parts you set down along the way.

Tools You’ll Need

A basic tool kit is included in the box, covering most of what’s needed. For reference, the key tools you’ll use throughout assembly are:

• 4mm Allen key (hex wrench) — used extensively for fender brackets, handlebar stem, and seat

• 5mm Allen key — for the seat post quick-release adjustment

• 6mm Allen key — for the handlebar stem clamp bolt

• 3mm Allen key — for securing fender position on the basket brackets

• 8mm socket/ratchet — for fender lock nuts

• 10mm socket/ratchet — for basket mounting bolts

• 15mm wrench — for the front wheel axle nuts

• Phillips head screwdriver — for the front fender bracket

• Box cutter or strong scissors — for zip ties and packaging

Lay all tools out before you begin. Having everything within reach prevents the frustration of stopping mid-step to hunt for a wrench.

Opening the Box and Removing Components

Start by cutting the outer tape and opening the top of the box. Inside, you’ll find the main trike frame surrounded by packaging foam and secured with numerous zip ties. Take your time here — do a full pass around the trike to locate and cut every zip tie before attempting to move anything. Missing even one can cause components to snag or shift unexpectedly.

As you remove components from the packaging, set them aside in groups: hardware bags (bolts, washers, lock nuts), the battery, the charger, the rear basket, the front wheel, the seat, and the fenders with their brackets. Having these organized before you begin assembly saves considerable time and prevents the common mistake of tightening one component before realizing another needs to go on first.

To get the trike itself out of the box, rather than trying to lift it out, cut two vertical slits at one end of the box to create a fold-down panel — essentially a loading ramp. This turns the box into a temporary garage door that lets you simply roll the trike out onto the floor. If there’s any chance you’ll need to use the box again (for storage or a return), tape along the slits after use to restore the box’s structural integrity.

Step 1: Installing the Front Wheel

Installing the front wheel is the logical first step because it puts the trike on all three wheels, making it easier to handle, position, and work on throughout the rest of the build.

Before inserting the wheel, note the orientation: the disc rotor — the circular metal disc attached to the wheel hub — must be positioned to slide between the brake pads on the fork. Look inside the front fork and you’ll see the brake caliper with its pads facing inward. The rotor needs to pass between those pads as you slide the wheel up and into the fork dropouts.

You may notice a metal rod or axle spacer inserted into the wheel hub during shipping — this is purely a protective measure to prevent the axle from bending in transit. Remove it before installation.

With the rotor properly aligned inside the caliper, slide the axle ends into the fork dropouts on both sides. Place a washer on each side of the axle, then hand-thread the axle nuts. Once both are hand-tight and the wheel is seated evenly, come in with your 15mm wrench and tighten both nuts firmly. These should be snug enough that the wheel has zero lateral play — apply solid force, but stop short of over-tightening, which can damage the dropout or thread.

The front fender arrives with its mounting bracket already attached. Before fitting it to the bike, use a Phillips head screwdriver to give the bracket bolt a firm snug-down to reduce any flex in the assembly.

The front light is zip-tied to its cable from the factory. Snip that tie to give the light free movement before mounting. The light has its own mounting clamp with a 4mm Allen bolt that controls the rotational angle — set this loosely for now, as you’ll fine-tune the angle after everything else is bolted on.

To mount the fender assembly, bring the fender in from the rear of the fork, passing its upper tab in front of the fork crown. The light mounts behind the fender at the same pivot point. Thread the mounting bolt through the light bracket and fender tab from the front, then add a washer and lock nut from behind. Don’t tighten fully yet — the fender needs to be able to swing up or down to align with the lower bracket points.

The fender also connects to two lower bolts on the fork legs. These bolts are pre-installed on the frame; remove them temporarily, position the fender bracket holes over the mount points, and reinsert the bolts with your 4mm Allen key. Again, leave everything at a snug-but-moveable tension until all four attachment points are in place.

Once all brackets are engaged, work the fender upward so it sits as high as possible — this maximizes clearance and ensures a clean line over the tire. Hold pressure on the fender with one hand (or have a second person assist) while tightening the top bolt with a 4mm Allen key and a 10mm ratchet on the lock nut. Work your way down to the lower bracket bolts and tighten those fully as well.

With everything tight, check the fender’s position relative to the tire. It should not contact the tire at any point when the wheel is spun. If there’s a rub, loosen the lower bracket bolts slightly, adjust the fender left or right, and re-tighten. Finally, adjust the light angle so it points forward and slightly downward, then lock its bolt in place. A loose fender is one of the most common sources of rattling on trikes, so take the time to get this right.

The handlebar stem inserts into the steerer tube of the fork. Before inserting it, remove the plastic cap from the steerer tube and set it aside — it will be replaced with a decorative cap that comes in the hardware bag. Note the orientation of the stem: the display cable should face forward, and the stem’s angled riser should face rearward toward the rider.

Slide the stem into the steerer tube and raise it to your approximate desired height. There is a maximum insertion line marked on the stem shaft — ensure the stem never sits higher than that line, as doing so risks the stem pulling free of the steerer tube under load. This is a critical safety point.

With the handlebar centered over the front wheel — visually align it by looking straight down over the stem — tighten the 6mm Allen bolt on the stem clamp. This bolt controls both height and rotation, so get it tight enough that the bars resist movement with firm pressure. A handlebar that rotates or drops under braking force is a serious hazard.

Once the stem is secure, press the decorative cap onto the top of the steerer tube and pop the plug into the stem opening. These are cosmetic touches that give the cockpit a finished look.

The handlebar tilt is controlled by two bolts at the top of the stem where the bar clamp meets the riser. Loosen these with a 4mm Allen key to adjust the bar angle. The ideal tilt depends entirely on your riding position and comfort — most riders prefer the bars angled slightly back for a relaxed, upright wrist position. Leave these bolts at a working tension during the first few rides and dial them in once you’ve settled on a position that feels natural.

The seat arrives pre-installed on the seat post. For most riders, the first order of business is finding the right height and tilt before riding.

Seat tilt is adjusted via a 6mm Allen bolt located beneath the seat. Loosening this bolt allows the seat platform to rotate forward or backward. Given the recumbent geometry of this trike — which places the rider in a low, reclined position — tilt preference varies significantly from person to person. A slight rearward tilt works well for many riders, but the best approach is to start neutral and adjust after a short ride.

Seat height is adjusted using the quick-release collar on the seat post. This is an important step that is easy to get wrong: the quick-release lever alone may not provide enough clamping force for a heavy rider or an aggressive riding style. To get a secure fit, use a 5mm Allen key in the slot located at the end of the quick-release bolt. Turn the Allen key clockwise to increase the clamping tension, then engage the quick-release lever. You’ll know the tension is correct when closing the lever leaves a visible imprint in your palm that lasts a few seconds. If the seat post still shifts under body weight after clamping, open the lever, add another half-turn of tension with the Allen key, and try again.

The battery ships separately inside its own box. Before installing it, locate the keys — they’re taped to the back of the battery box and easy to miss if you discard the packaging without looking.

The battery mounts to the frame via a sliding rail and locking mechanism. To install, align the battery with the mounting rail on the frame — there is a single primary slide point that acts as a guide. Once aligned, lower the battery onto the rail and slide it downward until it clicks into the locked position. The click is distinct; if you don’t hear and feel it, the battery is not fully seated and may dislodge during riding.

The keys are used to lock the battery to the frame — a theft-deterrent feature. The keys are not required to power the system on or off; electrical operation functions independently of the lock. Keep the keys somewhere accessible but secure, as they’re also used to remove the battery for charging away from the bike.

The rear basket is one of the more involved assembly steps, but it follows a logical sequence. The basket itself is pre-formed; your task is to attach the rear fender brackets and then bolt the whole unit onto the frame.

Attaching the Rear Fender Brackets

Locate the four mounting brackets from the hardware bag. These have a shorter leg and a longer leg; the shorter leg faces outward, toward the fender. Pre-drilled holes on the basket sides accept the bracket bolts, which are included in the basket packaging.

Hold each bracket against the basket so its angle matches the welded bracket angle on the basket wall — they should be flush and parallel. Use your 4mm Allen key to thread in the first bolt, get it snug, then position the second bolt hole and tighten that down as well. Work through all four bracket positions before moving on. The goal is brackets that are firmly fixed and flush against the basket wall with no rotational play.

Positioning and Locking the Rear Fenders

Each rear fender slides horizontally within its bracket, which allows you to fine-tune the fender’s lateral position relative to the tire before locking it in. The safest approach is to position the fender in the middle of its available range, then check clearance after the basket is mounted. The fender must not contact the tire on either side when the wheel is spun.

To lock the fender position, use a 3mm Allen key on the bolt face and an 8mm socket on the lock nut underneath. Tighten firmly, but be cautious not to strip the 3mm bolt head — it’s smaller and more vulnerable to over-torquing than the larger fasteners used elsewhere on the bike.

Mounting the Basket to the Frame

The frame has four pre-installed bolts at the rear platform where the basket mounts. Remove all four bolts and set them aside with their washers and lock nuts.

Lower the basket onto the frame platform and align the basket’s four mounting holes with the holes in the frame. It helps to look down through each hole to confirm alignment before inserting any bolts. Pass all four bolts through the basket and frame holes before tightening any of them — getting one bolt fully tight before the others are in place makes it difficult to align the remaining holes.

With all four bolts inserted, add a washer and lock nut to each bolt from underneath the frame. Use your 10mm socket on the nut and a 4mm Allen key on the bolt head above to tighten each mounting point. Work in a cross pattern — tighten opposing bolts sequentially rather than going around in a circle — to keep the basket seated evenly. Bring all four to a firm torque, not so aggressive that you risk cracking the basket material, but firm enough that the basket doesn’t shift when weight is applied.

Tire Pressure: Finding the Right PSI for Your Ride

With assembly complete, the next thing to address before riding is tire pressure. The recommended pressure is printed on the sidewall of each tire — on the Relaxed Body Recumbent, that’s 40 PSI. This is a starting point, not a fixed rule.

Higher pressure (closer to 40 PSI) reduces rolling resistance and makes the trike feel more responsive and efficient on smooth pavement. Lower pressure absorbs more vibration and makes for a cushier ride on rough surfaces or packed gravel. Many riders find a middle ground around 35 PSI offers a good balance of comfort and efficiency.

When inflating the tires for the first time, keep an eye on the tire bead — the edge of the tire that seats against the rim. Inflate slowly and check that the bead is seating evenly on both sides of the rim as pressure increases. If the tire appears to be bulging unevenly at any point, release pressure and reseat the bead before continuing.

How to Operate the Relaxed Body Recumbent E-Trike

Assembly is only half the story. Understanding how to operate the trike’s electrical system confidently is what unlocks the full experience. Here’s a complete walkthrough of the controls.

Powering On the Battery and Display

The battery has its own power button located on the battery casing. Press and hold it until the indicator lights illuminate — they will glow pale blue or green depending on the unit. The battery must be powered on before the display will respond.

With the battery on, press and hold the display power button on the handlebars for approximately two seconds, then release. The M5 display will light up and show current speed, pedal assist level, battery life, and odometer.

Understanding the Parking Brake

The Relaxed Body Recumbent E-Trike is equipped with two parking brakes — one on each rear brake lever. These are particularly useful when mounting or dismounting the trike, or when parked on any incline. To engage a parking brake, pull the brake lever fully and press the lock pin inward while holding the lever — then release the lever and the brake stays engaged. To release, simply pull the brake lever again, which pops the pin free.

One important note: when a parking brake is engaged, the motor is disabled. If you power on the trike and the display throws an error code, check both parking brakes first. Releasing them will clear the error and restore normal motor function.

Pedal Assist Levels

Pedal assist is the heart of the e-trike experience. The system uses a sensor to detect when you’re pedaling and supplements your effort with motor power — the higher the assist level, the more the motor contributes. The Relaxed Body Recumbent offers five pedal assist levels, displayed as “P” on the M5 display.

Use the up and down buttons on the display to cycle through levels 1 through 5. Level 1 provides a gentle boost, extending your range and reducing fatigue on long rides. Level 5 delivers maximum motor output, making hills manageable and reducing the physical exertion required significantly. You can change pedal assist levels whether you’re stationary or moving — there’s no need to stop.

Using the Throttle

In addition to pedal assist, the trike features a twist throttle on the right handlebar. To engage it, twist the throttle grip toward you — the motor will power the trike forward without any pedaling required. This is particularly useful for getting started from a stop or navigating short sections where pedaling isn’t practical.

Note the kill switch on the throttle: this is a small button that must be pressed in for the throttle to function. If the throttle appears unresponsive, check that this switch is engaged. When the kill switch is in the “out” position, the throttle is intentionally disabled — a useful safety feature if you want to prevent accidental throttle activation.

The Front Light

The integrated front light is controlled directly from the display. To turn it on, press and hold the plus (“+”) button. To turn it off, press and hold the same button again. The light is powered by the battery, so keeping it off when it’s not needed helps extend your range.

Reading the Battery Indicator

The battery indicator on the M5 display is a dynamic, predictive gauge rather than a static readout. It estimates remaining range based on how you’re riding at that exact moment. If you’re climbing a hill at level 5 assist, the gauge may drop noticeably. When you crest the hill and resume flat riding at a lower assist level, it may recover. This is normal behavior and reflects the system’s live energy calculations.

The practical implication: don’t panic if the gauge dips on a climb. And don’t wait until it reaches zero to head home. Experienced e-trike riders typically plan their route to return before the battery drops below two or three bars. Running a lithium-ion battery fully to zero repeatedly degrades cell capacity over time — keeping it topped up above 20–30% on a regular basis extends the battery’s useful life significantly.

Gearing and Shifting

The trike ships with its gearing pre-tuned from the factory. The shifter is located on the left handlebar; press the upper button to shift up to a harder gear, and the lower button to shift down to an easier gear. The display or a cable-actuated derailleur indicator will reflect the current gear position.

One important rule with any derailleur-based drivetrain: shift only while the pedals are turning. Shifting while stationary can force the chain against the derailleur under tension, which can bend the derailleur hanger or damage the chain. This applies to the rear derailleur on this trike. As long as you’re pedaling — even gently — the shift will be smooth and clean.

How to Charge the Battery

Charging the Relaxed Body Recumbent E-Trike is straightforward. The charger included in the box has a two-part connection: the charger unit itself, and a cord that connects the charger to the bike’s charging port.

The charging port is located on the side of the battery. Lift the protective rubber cover to expose the port, then insert the charger connector. Plug the other end into a standard household outlet. A charge indicator light on the charger will confirm the connection is active.

You have two options for charging: with the battery mounted on the trike, or with it removed. Both methods work equally well. Removing the battery is convenient if you want to charge in a different location from where the trike is stored — inside an apartment, for example, while the trike stays in a ground-floor storage area.

A full charge from fully depleted takes approximately 6 to 8 hours. In practice, you’ll rarely be charging from zero — topping up after a ride typically takes 2 to 3 hours. The charger is designed to stop automatically when the battery is full, so there’s no risk in leaving it plugged in overnight if needed.

Post-Assembly Checklist: Before Your First Ride

Before heading out, run through this quick checklist:

• Front wheel axle nuts are tight and the wheel spins freely without wobbling

• Disc rotor sits centered between brake pads and does not rub when the wheel spins

• Front fender does not contact the tire at any point through a full wheel rotation

• Front light is angled forward and its mounting bolt is tight

• Handlebar stem bolt is fully tightened and the bars do not rotate or drop under firm pressure

• Handlebar tilt bolts are set at your preferred angle and tightened

• Seat height and tilt are locked in — test by pressing firmly down on the seat to confirm no movement

• Battery is fully seated and clicks into the locked position; keys are stored safely

• Basket mounting bolts are tight and the basket does not shift when you apply lateral pressure

• Rear fenders are positioned clear of the tires

• Tires are inflated to your preferred pressure (reference the 40 PSI maximum on the sidewall)

• Both parking brakes release cleanly

• Display powers on and shows no error codes with parking brakes released

• Throttle responds when the kill switch is engaged

• All pedal assist levels cycle through without display errors

If the brakes feel soft or the gears skip under load, the system may need a minor tune-up after the first few miles of riding — cables stretch slightly as they seat in. Sixthreezero has adjustment guides available for both disc brakes and derailleur tuning if you’re comfortable making those adjustments yourself. If not, any local bike shop can perform a cable-stretch adjustment in under thirty minutes.

Tips for Getting the Most from Your Recumbent E-Trike

Start with Lower Assist Levels

It’s tempting to ride at level 5 from the first day, but starting at levels 1 or 2 gives you a chance to get comfortable with the trike’s handling, learn how it responds in turns, and preserve battery range for longer exploration. Many riders find level 2 or 3 ideal for casual flat-ground riding, reserving higher levels for hills or headwinds.

Take Time to Dial In the Fit

The recumbent seating position is different from any upright bike or trike, and it often takes two or three rides to settle on the ideal combination of seat tilt, handlebar height, and bar angle. Don’t over-tighten the adjustment bolts in the first session — leave yourself room to experiment. Once you’ve found positions that feel right, then lock everything in firmly.

Charge Before Storage

If you plan to store the trike for more than a week or two without riding, charge the battery to around 60–80% before storing rather than leaving it fully depleted or fully charged. Lithium-ion cells age most gracefully when stored at partial charge in a cool, dry environment.

Keep an Eye on Tightness Over Time

Vibration from riding gradually works bolts loose — this is true of any bike or trike. After the first 50 miles, do a full pass over the basket bolts, fender bolts, and seat post clamp to confirm nothing has backed off. After that, a monthly check of critical fasteners (axle nuts, stem bolt, basket mounts) keeps everything safe and rattle-free.

Final Thoughts

The Sixthreezero Relaxed Body Recumbent Electric Trike is engineered to deliver comfort and accessibility without asking riders to sacrifice capability. The recumbent seating position takes pressure off the lower back, wrists, and joints — which is why this trike resonates so strongly with older adults, riders managing chronic pain conditions, and anyone who has found upright cycling increasingly uncomfortable.

Assembly takes most people between one and two hours on a first build. The process is methodical and largely intuitive, and every tool you need ships in the box. The most important principle throughout: install everything loosely, confirm alignment, and tighten progressively. Rushing to a final torque on the first bolt of any assembly step almost always creates problems at the next one.

Once the trike is assembled and dialed in, what follows is genuinely one of the most enjoyable riding experiences in the electric trike category — a low, stable, powerful machine that makes miles feel effortless and encourages riders to stay active longer, go farther, and enjoy the ride on their own terms.

For additional questions about your trike, Sixthreezero’s customer support team is available at sixthreezero.com or by phone. Additional videos covering display configuration, brake adjustment, derailleur tuning, and riding tips are available on the Sixthreezero YouTube channel.