How to choose a motor wheel for a bicycle – types and recommendations

City, road, and mountain electric bikes will quickly get you to your destination, will not make you stand in traffic jams, and will not require the cost of oil and fuel to fill up the engine. People who have decided to buy a new-fangled vehicle or to convert their own bike into an electric, wonder what motor wheel to choose for a bicycle, so as not to make a mistake. Some will easily climb Uphill—how-to-learn–tips without noticing the headwind. Others are focused on maximum mileage and speed. Each type has both advantages and disadvantages. We will try to informatively help with the right choice.

Types of electric bicycle wheels

Manufacturers offer beginners and experienced users bikes that have electric motors instead of conventional wheels. They resemble a large bicycle fork, spliced into the wheel rim. The type of electric motor is selected according to traction and speed requirements and operating conditions. Motors that are installed in the wheel are divided into three types:

• geared;
• direct-drive;
• carriage.

The chosen wheel models must meet the technical parameters (voltage, power, weight, moisture protection, etc.). For example, an electric wheel built into the carriage allows simultaneous rotation of the pedals.

Motor wheels with a reducer are popular. The device increases the torque, which allows free rolling when the electric motor is disconnected. Geared motor wheels are characterized by their light weight and size.

The simple direct-drive design consists of no auxiliary transmission parts; generates power going to the battery of the electric bicycle; when braking, it operates in generator mode.

Geared

The main companies producing bicycle motors are located in China. In the ranking of the best manufacturers there are brands Bafang, MXUS, Golden Motor, Pasion eBike. Features of geared electric wheels:

1. The lightweight motor does not interfere with pedaling.
2. The cyclist freely overcomes steep climbs.
3. The electric motor together with the planetary gear is installed in the wheel hub.
4. Gears are made of plastic.
5. An overrunning clutch is installed, which transmits torque only in one direction (from the motor).
6. The electric motor is disengaged and does not interfere with the rotation of the wheel when the transmission is reversed.

Geared electric wheels come in two varieties. Speed wheels achieve maximum performance during slow acceleration. Traction wheels are the opposite.

For example, the lightest Bafang bikes (2 kg motor weight) operate at 350-500W. The bike accelerates to 35km/h in 10 seconds. The MAC bicycle wheel, designed by order of the Americans, weighs 4.4 kg. With 1000W power the bike reaches a speed of up to 55 km/h.

Advantages and disadvantages

The positive characteristics of geared motor wheels include:

• better efficiency with a large speed range;
• low weight and size;
• free rolling;
• low power consumption;
• easy overcoming hills;
• no resistance to movement when pedaling.

Cons:

• Standard equipment does not allow you to develop a lot of speed, get power more than 1000W;
• insufficient reliability of the motor-wheel;
• Plastic gears which are easy to cut off teeth;
• if the overrunning clutch is damaged, you will have to work only with the pedals.

Hardtail

A motor of this type is easy to install on the wheel, turning an ordinary bike into an electric bike. Expensive models come with built-in motors with a complete package. The direct-drive motorwheel does not have a gear transmission, characterized by a longer service life compared to other types. A simple device consisting of a rotor and stator is installed on the front, rear or both wheels at the same time. Power is used to achieve high speeds. The indicator is related to the type of MC and battery, has a range from 150 to 2000W. For example, the dynamics of an electric motor at 1500W is compared to a scooter. The motor wheel quickly accelerates to a speed of 50kph, which is 50% faster than a 1000W motor. Hall sensors are installed on all models.

Advantages and disadvantages

Advantages of the motor wheel:

• simplified design;
• easy assembly;
• inconspicuous position on the bike;
• quiet operation;
• increased efficiency;
• ability to accelerate up to 60 km/h on level roads;
• reliable design does not require maintenance.

Minuses of MK:

• high weight (up to 6 kg and above) and the size of the motor wheel;
• in case of breakage of at least one of the three sensors the motor-wheel will stop working;
• poor efficiency at low speeds and on climbs;
• use of a weak controller and charger reduces motor power;
• resistance to movement is present.

Wheel motor power

When choosing an electric bicycle, consumers first of all study the characteristics of the model, which depend on the purpose of the ride. At the same time, geared motor wheels are twice as powerful as direct-drive ones. The motor of the required power is selected according to the value of speed and traction characteristics. The index has a big range (150-3000W) and higher. For example, the company Free Eco Energy has released motor wheel Quanshun 3000W. The maximum power of the motor is 3 times the rated power (9000). The value is determined not by the motor, but by the controller.

Bench measurements on simulators determined performance suitable for the purpose of riding.

Parameters of electric wheels

Each manufacturer tries to make an electric bike reliable, high quality, affordable. Speed, brand, power, motor weight, wheel axle diameter – the main indicators of any model. The more expensive the bike, the lighter its weight. For example, for urban MK normal weight is 23 kg. For riders who ride around town at a speed of 30 km / h, suitable compact geared motors with a capacity of 350W. The technical parameters of the chosen model should correspond to:

• the specifics of use;
• the rated power;
• weight
• the materials of manufacture of the motor-wheel;
• type of installation;
• pavement characteristics.

Weight

Motor wheels, chargers, features of component parts form the weight of the electric bicycle. The greater the weight, the higher the power. For example, direct-drive MCs are heavier than geared ones with equal power. The weight of an electric wheel at 5000 watts is more than 13 kg, which increases the consumption of the battery. An alternative to the heavy-duty types is an electric motor for 1000-1500 watts. It weighs 4-5 kg and is designed for riding on mountain or hilly roads. The Bafang 250-watt geared motor weighs only 2 kg. The 1500W direct-drive motors at 8-9kg help achieve 50kph. So how do you choose the right model for the weight?

1. When riding in the city or rough terrain at a speed of 35 km / h, choose a motor weight of 4 kg and capacity of 250W.
2. If you decide to transform your bike into an electric bike, moving 50 km/h, buy a MC that weighs more than 12 kg (taking into account the weight of the battery).
3. At 90 km/h, the motor weighs 35 kg or more.

Weight categories:

• maximum lightweight – 1.4 kg;
• lightweight – 2,5 kg
• medium – 5-6 kg;
• heavy – 10 kg and more.

Axle diameter

The dimensions of the wheel are an important parameter when choosing an electric motor. MCs differ in axle diameter (12, 14, 16 mm), installed on the bike with a slotted or standard ratchet. Smaller wheel reduces speed, but increases traction. The Uphill—how-to-learn–tips ride is equally successful on a 28 rim bike and a 350W geared motor with 15-inch wheels. When placed on the bike, optimum weight distribution on the axles is achieved.

Width for different types of dropouts

The unusual term is called the seating for the wheels (ears). Dropouts are divided into two types:

1. Horizontal ones resemble an elongated wrench, the distance margin on which allows you to adjust the position of the rear wheel and the tension of the chain.
2. Vertical mounts are present on speed bikes that have a gearshift system. This type does not change the position of the wheel and chain.

The distance between the lugs is determined by the lower ends and only in the horizontal position. There are width standards for different types of dropouts. For example, for single-speed models it is 110 mm. Extreme riding bikes – 150 mm. Road bikes – 126 and 130 mm. For most models to mount a motor wheel, the front fork is 100 mm, and the rear fork is 135-145 mm.

Three important points:

1. Because of the heavy weight, high speeds, load on electric bicycles, the destruction of the dropouts increases the risk of severe consequences. Therefore, to equip MK choose bikes with a steel shock-absorbing fork at the front and sturdy lugs at the back.
2. Models with thin rear wheel seats are not suitable for mounting an electric motor.
3. We recommend the use of dropout reinforcements, which ensure safe riding on off-road and bumpy roads.

Components for electrifying a bike

A regular bike becomes electric when additional devices are installed. Professionals recommend using inexpensive Volta bikes components, which have received top marks compared to production models. The following components will be needed for electrification:

• an electric motor built into the wheel;
• rechargeable battery (power supply);
• a controller that supplies current to the motor and maintains speed;
• a throttle knob that regulates the voltage;
• brake sensor;
• a bicycle computer (optional).

The MC is fitted with double rims with thick spokes, which compensate for the load of increased torque.

Recommendations for the choice of motor wheels

Analysis of possible uses of MC, testing the existing models allow to give 9 tips:

1. If you will ride at speeds up to 40 km / h, choose a geared electric wheel. Above the index buy MK direct-driven.
2. For riding in the city sufficient motor power – 250W. For steep climbs need a motor-wheel at 1000-1500W.
3. Give preference to bicycles with good shock absorbers, so you will not knocked out of the saddle even on a small hole at a speed of 50 km / h.
4. Before choosing a model, decide on the type of motor that is suitable in terms of power to your riding goals.
5. The type of mounting and width of the frame is important. If the design of the bike does not allow to place the MC back (the presence of foot brake, planetary hub, expensive transmission), it makes sense to install a front wheel motor.
6. Selected MCs must meet the technical parameters.
7. For compact travel it is worth paying attention to the dimensions of the electric bike. The best option – a low folding frame, wheels up to 20 inches, the presence of front shock-absorbing fork.
8. The body of the motor should be strong and reliable. The presence of protruding parts, non-technological slots, poorly painted parts is unacceptable.
9. On quality MCs, there is necessarily an engraving of the company-manufacturer, serial number, model code, power.

Conclusion

Manufacturers offer a large selection of bicycles, clothing accessories, design of electric wheels. To control the speed for traffic safety in Europe and Japan are made MCs with a capacity not exceeding 250W. In the U.S., the limit is set only on the speed (30 km / h). We hope that our information will help you choose an electric bike with the desired characteristics.