Serija Q140MD

With a ready-to-ride weight between 60–70 kg and peak electrical output reaching 25 kW (e.g., 72V, 350A), the Q140MD delivers serious power. Whether you’re tearing through trails or cruising city streets, this machine is built to perform.

At the heart of the Q140MD is a design centred on robustness and minimalism. The motor is ingeniously positioned at the swing arm pivot point, eliminating the need for chain guides. This not only reduces mechanical complexity and maintenance, but also lowers operational noise. Thanks to the low-RPM BLDC out-runner motor with direct throttle response and high torque output a primary reduction is not necessary.

The unique shell frame design does more than support the structure—it also serves as a watertight battery compartment. This dual-purpose feature eliminates the need for an additional battery housing, reducing both weight and part count. Similarly, the motor axle doubles as the swing arm axle, again cutting down on components and enhancing overall efficiency.

The Q140MD features a modular design, allowing users to configure the bike as either a pedal-equipped electric bicycle or a full-fledged electric motorcycle. A wide range of add-on options is available, giving riders the freedom to upgrade and customize their setup over time. There’s no need to start with the full package—you can build and enhance your ride step by step, based on your needs and preferences.

The Q140MD uses high-strength Cr-Mo steel (1200 N/mm² tensile strength) with wall thicknesses of just 1–2 mm, making it lighter than many cast aluminium counterparts while maintaining exceptional durability and flexibility. For side plates and brackets, premium 7075 aluminium is used, ensuring a tough yet lightweight build.

• New top-loading design with a lockable hood for security.
• Battery charging port located directly on the battery pack, allowing external charging.
  • Anti-tampering features ensure only the owner can access the charging port.

• Top-Loading (QRBS System – Green Opening)

For quick and convenient battery installation, use the Qulbix Removable Battery System (QRBS) with the top-loading hood. Compatible batteries are available in the Qulbix shop, or you can build your own to fit the system.

• Side-Loading for Maximum Capacity (red opening)

To maximize battery size and capacity, use the side opening for installation. Shape the battery pack to match the side cut-out, allowing for a higher cell count. You can either build your own high-capacity pack or explore battery kits available in the Qulbix shop.

The top hood compartment remains usable as a convenient storage space, even with a side-installed battery.

Side installation of the battery

This way a larger capacity battery can be fitted in the shape of the frame side opening, but can not be installed from the top and QRBS system can not be utilized. A top hood opening is still operational that way allowing riders to use the upper part of the frame as a storage compartment. To be able to tighten the right side-plate from the outside (after the battery is inserted) a M6 thread must be cut in to the frame’s mounting holes and the M5 bolts need to be replaced by M6 bolts.

• Sport Use: Quick battery swaps between heats for uninterrupted track riding with two batteries.
• Commuter Use: Easily remove the battery for charging at work or in apartments where charging isn’t available, making theft more difficult.
• Traveling Use: You can use the extra space under the hood and seat for an on-board charger. This enables charging the bike on the go using 110-240VAC outlets available along your route.
• Extremely cold environments: For maximum range in cold environments, charge the battery indoors at room temperature before placing it in the vehicle. This ensures full capacity and prevents the 30% or more reduction in range that can occur when starting with a cold battery.

• The frame accommodates a double column of 21700 Li-ion cells, offering a lot of different possible battery configurations: between high-voltage 10P26S (110V) or 84V 12P20S.
• DIY builders can purchase a QRBS battery build kit (or complete, ready to install battery), with vibration reduction padding included.

Battery Charging

We’ve redesigned the charging process for added convenience. The charge port is now integrated directly into the battery pack inside the frame, eliminating the need for an external port.

Battery Anti-Tampering Measures

Improved anti-tampering features ensure secure charging, even when the battery is charged outside the frame. The charging port is protected by a lock, accessible only to the owner. Additionally, when charging on board, the hood can be lowered and locked, allowing only the charger cable to exit the frame—perfect for charging in public spaces.

Redesigned moto seat: over 600 mm long and 180 mm wide for improved comfort and control.

• Waterproof storage compartment under the hood, secured with a lock.
• Additional space under the seat for tools and essentials. A small charger can also be stored inside the compartment.

The unique shell frame design does more than support the structure—it also serves as a watertight battery compartment. This dual-purpose feature eliminates the need for an additional battery housing, reducing both weight and part count. Rear shock bracket has also the following adjustment options:

• Adjustable rear ride height: The adaptive rear shock bracket allows quick and easy height adjustments.
• Rotatable bracket: Rotate the bracket to raise or lower the seat position to fit your riding style or terrain.
• Tuneable suspension feel: Experiment with different rear shock mounting positions to dial in a softer or firmer rear end, depending on your preference.

The Q140MD swing arm is designed for performance and simplicity. Its pivot point aligns with the motor’s chain wheel, keeping chain tension constant during suspension movement—no need for extra chain guides or tensioners.

With the motor axle doubling as the swing arm pivot, there are fewer parts, less weight, and lower maintenance. Made from high-strength Cr-Mo steel, it handles the torque of the QS V3MD motor with ease, ensuring a stable, quiet, and reliable ride on any terrain.

• Fewer parts, less hassle: The motor axle also serves as the swing arm pivot, reducing part count and overall weight.
• Chain stays tight: Swing arm pivot is aligned with the motor’s chain wheel, so the chain length stays constant during suspension movement—no need for chain guides or tensioners.
• Built tough: Made from high-tensile 1200 N/mm2 Cr-Mo steel to handle the torque of the QS V3MD motor without flex.
• Quiet and reliable: Fewer moving parts mean lower noise, less maintenance, and more durability in all conditions.
• Adjustable rear ride height: The adaptive rear shock bracket allows quick and easy height adjustments.
• Rotatable bracket: Rotate the bracket to raise or lower the seat position to fit your size
• Tuneable suspension feel: Experiment with different rear shock mounting positions to dial in a softer or firmer rear end, depending on your preference.

• Designed for stability across various terrains, with a 64° steering head angle and adjustable height.
• Recommended Fastace suspension for smooth handling and performance.

The motor which is used in the Q140MD bike is Qulbix version of QS 205 50H V3MD motor, available in Qulbix store.

The motor’s continuous power rating refers to the maximum mechanical power output the motor can sustain for 15 minutes (or 30 minutes under more demanding protocols) without exceeding its maximum operating temperature (e.g., 140°C). Sustained high temperatures can degrade motor magnets and lead to irreversible demagnetisation, making effective motor cooling critical, particularly at higher phase currents.

Continuous power testing is an endurance benchmark — comparable to maintaining steady power while driving uphill for 15 minutes.

• The standard V3 hub motor delivers 3000 W of continuous power without any additional cooling measures.
• When enhanced with Ferro fluid (FF) and rotor fins, continuous output increases to 5000–6000 W (Qulbix V3MD motor version).
• For even higher performance, the RACE version of the Q140MD motor combined with advanced cooling solutions allows operation with controllers and battery systems supporting up to 25 kW of electrical input power (e.g., Fardriver ND72680, Nucular P24F).

At these extreme levels (e.g., Fardriver ND72680 is capable of delivering up to 680 A phase current), maximum power output is intended for short bursts — typically around 5 seconds — to ensure system reliability and thermal safety.

Q140MD frame is also compatible with standard “in-wheel” QS 205 50H V3 motor (spoke ring does not need to be removed). That way everyone who has a hub-driven e-bike can transform it in to this high performance machine.

The controller is mounted high in the front of the frame, a position chosen for optimal airflow and protection from debris. The external setup not only improves cooling but also allows for quick swaps and compatibility with a range of controller types.

The Q140MD frame is compatible with a wide range of controller brands, including:

• • Fardriver
  • Nucular
  • Votol
  • Sabvoton
  • Kelly
  • Other brands (e.g., Adaptto, Crystalyte, etc.)

The frame features a standardised mounting position designed to accommodate a controller bracket. Each controller type has its own bracket, ensuring a sleek appearance and a secure connection to the frame.

• Compatible with older Q140MD models for easy upgrades (new Q140MD Frame is compatible with older model swing arms and vice versa).
• Multiple controller installation options with protective covers and brackets available.

• Locked hood and Ignition key switch for enhanced security
• Optional steering lock for added anti-theft protection.

The brakes feature 4-piston calipers with adjustable levers and a large mineral oil reservoir with an oil level indicator. The 203 mm diameter disc rotors are 2.4 mm thick, providing strong stopping power, preventing fading, warping, and squeaking, while offering greater resistance to bending. Additionally, the brakes include brake activation switches (depending on the model) to control brake lights or cut power when the PAS (pedal assist) system is engaged.

Transform your ride into a street-ready powerhouse with our premium 12V components and DC-DC converter, reducing battery voltage (up to 84V) to 12V. Our selection of lights, blinkers, horns, and brackets ensures a smooth upgrade for road readiness. For top performance and safety, choose our motorbike-grade e-mark front headlamp, tail-light with brake and license plate lights, and a specially designed headlamp bracket set with horn and blinkers.

Road legal set for Q140MD

Complete road legal set of plug-and-ride wiring harness with 12V DC-DC converter, headlamp, rear lamp, blinkers, controls etc. is available in the Qulbix shop.

Foot pegs and/or pedals can be chosen based on preference.

The adjustable kickstand features a two-part leg, allowing you to adjust its length. When the kickstand is down (parked), it activates a kill-switch to disable the motor, preventing the vehicle from moving while parked or during charging (if the key switch is on and the throttle is accidentally turned). This serves as a safety feature.

The Q140MD frame kit is tailored for DIY enthusiasts and electric bike manufacturers, providing multiple configuration options to build a versatile vehicle with up to 30 kW of pure electrical power. Visit our YouTube channel @QULBIXPerformanceElectricBikes for various build videos and instructions on how to create your dream bike.