⬇️ Download the EKX X21 User Manual (PDF)

Quick Specifications: EKX X21 #

How the X21 Differs Within the EKX Series #

All EKX models (GTS, X21, X21 MAX, X20) share the same manual framework, frame architecture, LCD instrumentation (Touch ID), removable battery system, and fault-code diagnostics. The X21 is distinguished by:

• Battery: 48V 35Ah pack — the highest capacity in the 48V fat-tire tier, versus the 48V 30Ah on the X20.
• Range: 150 km factory-rated riding distance, 30 km more than the X20, with the same 150 kg load capacity.
• Wheel: 20×4.0 fat tire, unlike the 70/100-19 off-road wheel on the X21 MAX and GTS.
• Motor: 2000W rated output — the same power class as the X20, below the 3000W X21 MAX.

Safety requirements, charging behavior, twist-throttle (TAG) operation, LCD controls, and troubleshooting procedures follow the universal EKX series protocol.

Part 1 — Before You Ride: Safety Requirements #

Essential Safety Warnings #

• Read this manual completely before riding your EKX X21 for the first time, and keep it in a safe place for future reference.
• Retain the original packaging for repackaging in case of return or product replacement.
• Follow the assembly instructions precisely and verify that no screws are loose before every ride.
• Wear a certified helmet and comply with all national laws and local traffic regulations.
• Check all data on your purchase voucher when buying, and keep all vouchers after the purchase is complete.
• Your first ride should take place in a controlled environment, away from cars, obstacles, and other cyclists.

Pre-Ride Mechanical Safety Checklist #

• Brakes: Confirm front and rear brakes work properly; brake pads must not be over-worn and must be correctly positioned against the rims; cables and levers must be lubricated, adjusted, and tightly secured.
• Wheels & Tires: Inflate tires to the pressure shown on the tire sidewall; check tread for bulges or excessive wear; verify rims run true and spokes are tight; tighten axle nuts or confirm quick-release levers are correctly tensioned and closed.
• Steering: Handlebar and stem must be correctly adjusted and tightened; verify the headset locking mechanism.
• Chain: Chain must be oiled, clean, and run smoothly — extra care is required in wet or dusty conditions.
• Battery Pack: Ensure the battery is in good operating condition and kept fully charged.
• Bearings: All bearings (headset, wheel, pedal, bottom bracket) must be lubricated, run freely, and display no excess movement, grinding, or rattling.
• Cranks & Pedals: Pedals securely tightened to cranks; cranks secure to the axle and not bent.
• Derailleurs: Front and rear mechanisms adjusted and functioning; shift levers and cables properly lubricated.
• Frame & Fork: Inspect for bends or cracks; replace damaged frame or fork components immediately.
• Accessories: All reflectors properly fitted and not obscured; rider wearing a helmet.
• Motor Drive & Throttle: All motor drive components correctly mounted and functioning.

Part 2 — Battery Care and Charging (48V 35Ah Li-Ion) #

Charging Protocol #

• Fully charge the battery before first use — batteries should be fully charged immediately when received and immediately after each use.
• Li-Ion recommended charge time: 4–6 hours. For a complete 100% charge, leave the battery on the charger for one full hour after the charger indicator light turns green.
• Never charge batteries for longer than 24 hours.
• Li-Ion batteries have no “memory” — partial discharge/charge cycles will not harm capacity or performance.

Temperature, Storage, and Range Factors #

• Rated output capacity is measured at 77°F (25°C). Temperature variation alters performance and shortens expected battery life; high temperatures especially reduce overall battery life and runtime.
• Batteries stored below 50°F (10°C) will show reduced range.
• Range is maximized by: continuous rider pedaling input, smooth terrain, tailwinds, proper tire pressure, lighter rider weight, and a properly maintained bicycle and battery.

Part 3 — Component Assembly #

Front Wheel — Quick Release Installation #

1. Remove the tension adjusting nut and one of the small springs, then slide the quick release skewer through the hub. For disc brake models, insert the skewer starting on the brake rotor side; replace the spring and tension adjusting nut.
2. If the bicycle has rim brakes, disengage them to increase clearance between tire and brake pads.
3. Install the wheel into the dropouts, making sure the quick release lever is on the left side of the bicycle.
4. Holding the quick release lever in the OPEN position, tighten the tension adjusting nut until it is finger-tight against the fork dropout, then swing the lever into the CLOSED position — the lever should leave a clear imprint in your palm.
5. Spin the wheel to confirm centering and brake clearance.

Warning: The full force of the cam action is needed to clamp the wheel securely. Holding the nut with one hand and turning the lever like a wing nut is NOT a safe or effective way to close a quick release. Failure to properly tighten the wheel connection may cause the wheel to dislodge.

Rear Wheel — Bolt-On Installation #

1. Loosen rim brakes as above (disc brakes require no adjustment).
2. Place the wheel into the frame dropouts and slide a washer onto each side of the axle.
3. Install axle nuts and tighten; confirm the wheel is centered in the frame.
4. Spin the wheel to verify centering and brake clearance.

Warning: Tighten both rear wheel axle nuts securely. Failure to do so may cause the rear wheel to dislodge from the dropouts, resulting in serious damage or injury.

Seat Height — Correct Saddle Position #

Set the saddle height according to the rider's leg length for the best pedaling efficiency. While sitting with one pedal at its lowest point and the ball of the foot on the pedal, the knee should be slightly bent; placing the heel on the pedal, the leg should be almost straight. The hips should not rock from side to side when pedaling.

Part 4 — LCD Display, Throttle, and Controls #

The X21's LCD screen (Touch ID) indicates speed, mileage, gear, headlight status, and PAS level, and provides fault warnings plus function settings. Controls include the power switch, setting button, gear increase/reduction buttons, electric speed button, brake levers with motor cutoff, and the accelerator.

TAG (Twist and Go) Operation #

• Turn the main power switch on, then begin riding as you would a regular, non-motor-assisted bicycle.
• After a few seconds the motor slowly activates and ramps up to 50% power; with the pedals in motion, slowly twist the throttle toward you to activate full motor power.
• The more you twist, the more power is applied — at full twist the motor accelerates to its full speed of about 18–20 mph (28–32 km/h) in standard assist operation.

Part 5 — Error Code Diagnostics (X21) #

Part 6 — Mechanical Troubleshooting #

Part 7 — Maintenance Schedule #

Follow the periodic lubrication and inspection intervals defined in the manual's maintenance chart, and refer to the torque values chart when tightening components — under- or over-tightened components may loosen or break, causing a fall. Consult a bicycle specialist if you have doubts or concerns about your experience or ability to properly assemble, repair, or maintain the bicycle.

Frequently Asked Questions — EKX X21 #

What motor and battery does the EKX X21 use? #

The X21 is equipped with a 2000W motor and a 48V 35Ah removable lithium-ion battery — the highest-capacity 48V pack in the EKX fat-tire tier.

How fast does the EKX X21 go, and what is its range? #

The factory-rated top speed is 55 km/h, with a maximum riding distance of up to 150 km per charge and a 150 kg load capacity. Actual range depends on rider weight, terrain, wind, tire pressure, and battery condition.

What is the difference between the EKX X21 and the X21 MAX? #

The X21 uses a 2000W motor, 48V 35Ah battery, and 20×4.0 fat tires. The X21 MAX upgrades to a 3000W motor, 60V 30Ah battery, and 70/100-19 off-road wheel, with the same 55 km/h top speed and 150 km range.

Does the EKX X21 use the same manual as the X20 and X21 MAX? #

Yes. All EKX series models (X20, X21, X21 MAX, X22, GTS) share the universal factory manual framework for safety, assembly, battery care, and maintenance. Only the specifications — motor power, battery capacity, and wheel size — differ by model.

What does error code E030 mean on the EKX X21? #

E030 indicates a Communication Failure between the LCD meter and controller. Check the communication harness for reversed wiring or breaks, confirm the controller and meter protocol match, and inspect the meter communication circuit for burnout.

How long should I charge the EKX X21 battery? #

Charge the 48V 35Ah Li-Ion battery for the recommended 4–6 hours, plus one extra hour after the charger indicator turns green for a complete 100% charge. Never exceed 24 hours of continuous charging.

What wheel size does the EKX X21 have? #

The X21 rides on 20×4.0 fat tires, unlike the 70/100-19 off-road wheels fitted to the X21 MAX and GTS models.

📎 EKX X21 User Manual — Free PDF Download