The RTUSUML 48V 1500W gearless rear hub motor at Amazon’s entry level price point on Amazon provides the highest dollar per watt value currently available. The motor is sold “bare” only, and includes no controller, no battery, no throttle, and no wiring. If you are a knowledgeable DIY ebike converter, or have parts lying around, the price is unbelievable. However, if you are a first time ebike converter looking for a “complete kit”, you will still need to purchase a number of additional products to be able to complete your build. Check today's price on Amazon before you decide.
Specifications and Motor Construction
The motor is a 48V 1500W brushless gearless direct drive hub motor, with a maximum output of 500 rpm and 55 nm of torque. Unlike traditional geared hubs, gearless motors contain no planetary gears within them. Therefore, they have reduced mechanical drag when you are pedaling and not using the motor, and a smoother feeling when the motor is coasting. one drawback to a gearless design is that it produces slightly less low-speed torque on hills compared to a similar wattage geared hub due to the fact that geared hubs create multiple levels of torque by multiplying the input torque through their internal gears. Therefore, if you live in an area with very hilly terrain, you may notice the difference in low speed hill climbing torque.
The motor accepts wheels ranging from 20 to 28 inches and attaches to standard 135mm (5.31 inch) rear dropouts on common steel or aluminum framed bicycles. The axle diameter is 5.45 mm. So prior to making a purchase, please measure your dropout width to ensure compatibility. The hub shell is threaded for a typical free wheel type cassette, therefore you will be able to install a wheel on it after acquiring the proper tools. The materials include. Aluminum for the outer casing of the motor, iron for the internal components of the motor, copper for the electrical winding components of the motor, and magnetic steel for the internal components surrounding the magnets. The weight is approximately 15.4 pounds. For budget tier applications such as this one, we do not expect polished finishes. In short, while the motor itself is functional and appears to be constructed adequately for a budget application, it is not going to win any beauty contests.
Included Components vs Excluded Components
There is an extremely important piece of information contained within this section that you absolutely must read prior to placing an order for this product. As stated earlier, this is simply the bare motor only. There is no controller included in the box. There is no throttle included in the box. There is no pedal-assist sensor (PAS) included in the box. There is no wiring harness included in the box. There is no display included in the box. And finally, there is no battery included in the box. You will need to acquire each of these products separately in addition to this motor in order to convert it into an operational electric bicycle.
As referenced previously, you can locate compatible controllers and accessories for this particular motor at the Amazon listing page. The seller also references potential pairing combinations for customers.
When selecting a controller for use with this motor, be sure to select a 48V 1500W controller with a minimum phase current of 24a. According to the seller, he recommends pairing this motor with a battery having at least a 50A current rating for optimal performance. Mid-ranged 50A or higher rated controllers cost significantly less than a full kit conversion system.
Additional accessory purchases required for completion of your conversion include. Thumb throttle, hall sensor cable, PAS sensor, and wire harness. Each of these can be purchased individually from the seller through Amazon. The largest single expense item remaining in completing your build will likely be your choice of 48V battery, including matching connectors based upon how much range you require.
Assuming you have acquired all of the necessary componentry for completion of your build, the estimated total cost of completion will typically fall in-line with industry standards based on your chosen battery size. Therefore, while you will still have to purchase all of the individual components needed to complete your build individually. You will save money over purchasing a name brand complete kit conversion system. Additionally, since you will be assembling your own conversion system. You will have more control over your final configuration to meet your specific needs as opposed to settling for an off-the-shelf complete kit configuration that was designed to meet average customer requirements.
If you would like more detailed comparisons between various complete kit options. Please reference our comparison article between various ebike conversion kits.
performance Expectations
A 1500 watt gearless electric bicycle motor running on a 48 volt system is significantly more powerful than most street legal electric bicycles permitted in various jurisdictions. Which typically have a 750-watt limit. You can anticipate accelerating from 0 mph to 20 mph in less than 10 seconds on flat ground with light rider weight. Your top speed should approximate 25 – 28 mph based on factors including tire pressure, total weight (including rider and cargo), and wheel gearing.
Note: wind noise dominates at speeds above approximately 20 mph, thereby masking any audible differences between the gearless design and its geared counterpart.
Heat Management
Similar to any high power electric motor. Long duration climbs produce Heat in this motor as well. To help manage excess Heat generated by prolonged hard use of the motor. External fins are molded onto the aluminum housing of the motor to provide passive cooling.
Properly sizing your controller with sufficient phase current headroom is critical for ensuring that the motor performs optimally when confronted with steep grades. An under-sized controller will limit your hill-climbing performance regardless of your controller’s rated output capability. Similarly, a weak battery will limit your hill-climbing performance regardless of how large the battery is or whether you have a properly sized controller installed.
Who Should Purchase This Product?
There are three types of customers that would benefit from purchasing this product:
First – experienced do-it-yourself ebike builders who already possess compatible controllers and batteries. Second – first-time-ebike-builders who wish to reuse existing components from previous builds and upgrade their power output with a cheap high-wattage hub. Third – custom bike manufacturers who desire an affordable high-torque hub option without the added expense associated with purchasing a complete kit conversion system.
This product is not intended for first-time ebike converts. Instead of purchasing this product, first-time builds should optimize their funds by purchasing a complete kit with everything needed including a controller, display screen, throttle assembly & wiring pre-installed. Completing a basic build through acquisition of a complete kit provides new builds an opportunity to learn the fundamentals of ebike conversion without getting stuck on a hub that spins but produces no power because they cannot connect the required components together correctly.
If you are unable to read a simple wiring diagram or have never used a soldering iron prior to attempting installation of an electronic component such as an ebike controller. this may not be the best starting point.
To gain further insight into the operation of these motors, we recommend visiting the Wikipedia page on motorized bicycles which contains information about hub-motor technology as well as the differences between direct-drive hubs and belt / chain driven systems.
If you already possess the skills and additional components necessary to create a functional e-bike using this hub. the price represents an excellent value for money considering the amount of power provided. If you are a new convert looking for a plug-&-play solution. we encourage you to browse our blog articles for beginner-friendly guides on building an ebike from start to finish, including frame selection & first ride.
Frequently Asked Questions
What Else Do I Need to Complete My Build Besides This Motor?
In addition to this bare hub-motor only. You will require a compatible 48-volt, 1500-watt or greater rated controller designed specifically for use with gearless hub motors. A matching 48-volt battery having compatible connections. A thumb throttle. Hall sensor wires. A pedal assist sensor for use in combination with a throttle or pedals alone. & general purpose wiring supplies. Depending upon the accessories you select to complete your build. the final cost could be at entry level prices when all items are combined.
Will This Motor Fit My Bike?
The motor fits conventional bicycles utilizing standard 135-mm rear dropout spacing & featuring a 5.45-mm axle diameter. It is suitable for wheels ranging from 20-inches up to 28-inches in size. If your bike features non-standard dropout spacing or quick release skewers. please measure before making any purchases. Both steel & aluminum frames will work fine as long as you install torque arms to handle the 55 nm of torque produced.
Is a Gearless Motor Better Than a Geared One?
Gearless motormotors are quieter operating than geared units due to the absence of internal planetary gears within them. Additionally, they exhibit reduced mechanical drag when pedaled unpowered & longer lasting cycles since there is less wear on internal moving parts. Conversely geared motormotors provide more low-speed torque via multiplication of input torque through their planetary gears. therefore more appropriate for riding areas with steep hills. Choose gearless for quiet cruising. geared for hill climb applications where both motors feature similar wattage ratings.
What Speeds Can I Anticipate?
Based upon flat ground riding conditions & assuming a lightweight rider. expect approximately 25 – 28 mph based upon factors including tire pressure & total rider/cargo weight. plus wheel gearing ratio when built out properly. Note that actual speed achieved will vary greatly depending upon local speed & power laws regarding ebikes in your area.