Tongsheng Mid-Drive Kit 48V500W review

Have you thought about turning your regular bike into a powerful assisted ride without buying a brand-new e-bike?

My Overall Impression of the Tongsheng Mid-Drive Kit with Battery(Optional) 48V500W Torque Sensored Drive Motor DIY Ebike Conversion Kit for 68-73MM Bottom Bracket Mountain Bike,Citybike,Tricycle

I installed the Tongsheng Mid-Drive Kit with Battery(Optional) 48V500W Torque Sensored Drive Motor DIY Ebike Conversion Kit for 68-73MM Bottom Bracket Mountain Bike,Citybike,Tricycle on my mountain bike and came away impressed by the smoothness and sense of pedal-on power. The torque-sensing motor brings a natural, proportional assistance that feels more like amplified pedaling than just a shove from the rear wheel.

Why I picked this kit

I wanted a conversion that preserved the bike’s handling and provided a realistic pedaling feel. The torque sensor and mid-drive placement made this kit attractive because they help retain bike balance and leverage drivetrain gears for climbing efficiency.

What’s Included and What You Should Expect

I paid close attention to the parts supplied and the extras I needed to source separately. A complete understanding of included components saves surprises during installation.

Included Item	Description
Mid-drive motor assembly	Tongsheng torque-sensored 48V 500W motor unit designed for 68–73mm BB shells
Bottom bracket spindle	Usually sized to fit the kit requirements; often integrated with motor
Controller and wiring loom	Necessary electronics to manage motor output and sensors
Display unit	Shows PAS level, battery voltage, speed (model-dependent)
Throttle (optional)	Thumb or twist throttle in some kits
Mounting hardware	Bolts, spacers, clamps for assembly
Instruction manual	Basic guide; often with diagrams but may require online resources
Battery (optional)	Some sellers offer an optional 48V battery — check capacity and connector

I found that packaging quality varied by vendor. The core mechanical parts were generally well-protected, but delicate items like the LCD and connectors benefit from inspection before installation.

Technical Specifications at a Glance

I like to have a concise spec sheet when I evaluate a kit. This helps compare it with other options quickly.

Specification	Typical Value / Notes
Motor type	Mid-drive, torque-sensored
Voltage	48V nominal
Rated power	500W
Bottom bracket compatibility	68–73mm shell width
Sensor type	Torque sensor (measures applied torque on pedals)
Assist modes	Multiple PAS levels; throttle optional (model-dependent)
Controller	Integrated controller with current limits; programmable on some models
Weight	Motor + spindle usually ~3–4 kg; battery adds more
Recommended bike types	Mountain bikes, city bikes, tricycles with compatible BB
Legal considerations	May exceed local e-bike power/speed limits — check regulations

These specs reflect the typical configuration for this Tongsheng variant. Actual numbers can vary slightly by batch and seller options, especially when a battery is included.

Installation Experience

I want to be realistic about difficulty: this is a DIY conversion but not a beginner’s weekend project unless you’re comfortable with bike mechanics.

Preparation and tools I used

I gathered a set of Allen keys, a torque wrench, a crank puller, bottom bracket tool (if needed), cable cutters, zip ties, and basic electrical tape. I also used grease and thread locker where appropriate.

I recommend laying out all parts and matching them to the manual before starting. That saves time when you reach the alignment and wiring stages.

Mechanical installation steps

I removed my cranks, old bottom bracket (if present), fitted the Tongsheng spindle/motor assembly, and reinstalled cranks compatible with the kit. I had to check chainline and adjust chainring position to compensate for the motor’s spatial footprint.

The mid-drive design makes the bike’s center of gravity slightly lower than a rear hub motor, which I appreciated for handling. However, installation required patience to ensure the motor sat correctly in the BB shell without binding.

Electrical hookup and display placement

I routed the wiring loom along the frame quietly and used zip ties to secure it. I mounted the controller in a spot with good airflow and protected from debris. The display was placed where I could read it easily without taking my eyes off the road.

Connecting the battery (if purchased separately) required attention to polarity and secure connectors. I tested continuity and launched a basic power-on test before final tidy-up.

Performance: Riding Feel and Power Delivery

This is where the torque sensor shows its value. I describe subjective performance along with measurable aspects.

Assistance is smooth and natural

I felt a proportional boost: the harder I pedaled, the stronger the assist, which resulted in very predictable acceleration and gear use. Unlike cadence-only systems that sometimes kick in abruptly, the Tongsheng’s response matched my intention to accelerate or maintain pace.

Climbing and torque delivery

On steeper grades, the kit’s combination of a 500W nominal motor and torque sensing let me climb using lower gears efficiently. I shifted as normal, and the motor worked with the drivetrain rather than against it, allowing for extended hill performance without overheating.

Speed and throttle behavior

With a 48V 500W unit, I found comfortable cruising speeds on flat terrain in the 20–28 mph (32–45 km/h) range depending on assistance level and rider weight. Throttle availability depends on the kit variant; I found throttle to be useful for low-speed maneuvering and quick starts, but I favored the torque-sensed PAS for sustained rides.

Noise and vibration

The motor isn’t silent, but it’s quieter than many hub motors. I noticed a subtle mechanical whine under heavy load, but it didn’t detract from the ride. The tactile feedback through the cranks felt solid without excessive vibration.

Battery Options and Range Estimates

Because the kit can come with an optional battery or as a motor-only kit, I tested different battery scenarios and share realistic range expectations.

Battery selection considerations

Battery capacity (Wh), cell quality (A-grade 18650/21700 cells), BMS features, mounting style, and weight all matter. For a 48V system, common capacities are 10Ah to 20Ah, translating to 480Wh to 960Wh.

I recommend choosing a battery with reliable BMS protection and a mount that fits your frame or rack. Removable downtube or rack batteries are convenient for charging indoors.

Range expectations

Range depends on rider weight, terrain, assist level, and battery capacity. From my riding:

• 480Wh (48V10Ah): 25–50 miles (40–80 km) easy-assist mixed terrain
• 720Wh (48V15Ah): 35–75 miles (56–120 km)
• 960Wh (48V20Ah): 50–100 miles (80–160 km)

I saw closer to the lower end of these ranges when I used higher assist levels and hillier routes. Conservative riding at lower PAS levels stretches the range significantly.

Charging and battery care

I charged batteries according to manufacturer recommendations, avoided full depletion, and stored at around 40–60% if I wouldn’t use the bike for weeks. That helped prolong battery life and maintain capacity.

Compatibility and Fitment

The kit specifies 68–73mm bottom bracket shell width. That range covers many common bikes but not all.

Bottom bracket types and what to check

I checked whether my bike used a threaded or press-fit BB. Many Tongsheng kits target threaded BBs within that width range. If you have a non-standard BB, you may need adapters or a different kit.

I also verified crank interface compatibility; some kits require specific cranksets or provide a new crank spindle that fits the OEM cranks. Measure the chainline and ensure the motor doesn’t interfere with frame elements like chainstays or guide mounts.

Frame clearance and drivetrain compatibility

The mid-drive will bring the motor into the BB area, so check that the frame has clearance for the motor bulk. Bikes with an internal cable routing choke point near the BB might need extra care routing the loom.

If you run a 1x drivetrain, expect fewer complications. With a triple chainring or certain chain guides, I checked that nothing would rub or misalign with the motor assembly.

Maintenance and Longevity

I want my conversions to last, so I treat maintenance seriously. The Tongsheng unit is robust but benefits from routine checks.

Routine checks I perform

I periodically inspect motor mounts, bolts, and the wiring loom for looseness or wear. I keep the spindle and chain well-lubricated and check torque specs on mounting hardware. I also examine connectors for corrosion and clean the display lenses for good readability.

Drivetrain wear and chain care

Mid-drives put more stress on the chain and cassette because the motor torque transmits through the gears. I switched to a slightly heavier-duty chain and replaced it more often than on an unassisted bike. Keeping the drivetrain clean and properly lubricated extended life and prevented early wear.

Servicing the motor

Tongsheng motors are generally sealed, but if I suspected an internal issue, I sought professional service rather than opening the motor myself. Regular inspection of bearings and listening for unusual noises helped catch issues early.

Troubleshooting Common Issues

During and after installation, some hiccups are normal. I list the ones I encountered and how I fixed them.

Motor won’t power on

I checked battery charge, wiring polarity, and fuse—some kits include an inline fuse. A loose connector or incorrect battery polarity is a frequent culprit. After verifying connections and the battery output, the unit powered up.

Jerky assistance or inconsistent PAS

If PAS behavior seemed erratic, I checked display settings and sensor alignment. Sometimes recalibrating the torque sensor or updating the display parameters (if supported) fixed the issue. Loose crank arms or worn chainrings can also cause inconsistent sensor readings.

Overheating under heavy load

Extended climbing at high assist levels can heat the motor and controller. I moderated assist levels on long climbs, and if overheating occurred often, I considered upgrading the controller or limiting continuous current via settings (if possible).

Strange noises or grinding

I inspected the bottom bracket shell fit and bearings. Noise often came from a misaligned spindle, loose bolts, or a poorly seated crank. Tightening to spec and ensuring correct spacing solved most of these problems.

Safety and Legal Considerations

I always check local laws because a 500W 48V system may exceed e-bike power restrictions in some regions.

Legal compliance

Some jurisdictions limit e-bikes to 250W or 750W, and maximum assisted speed may be regulated. I recommend researching local e-bike classifications and ensuring you comply with licensing, helmet requirements, and other rules.

Riding safety

Because a motor increases speed and torque, I upgraded my brakes where necessary and made sure tires were rated for the higher average speeds. I also practiced starting and stopping in a controlled area to get a feel for the power delivery.

Customization and Tuning

The kit can be adapted or tuned in a few ways to match my preferences.

Controller tuning and PAS mapping

Some Tongsheng controllers allow tweaking of assist curves and current limits. I adjusted assist aggressiveness to achieve a more relaxed power delivery during city commuting and a stronger response for hill climbs.

Choosing sprocket and gearing

I experimented with smaller chainrings and wider-range cassettes to optimize hill performance. Using a lower gear ratio on the chainring reduced strain during steep climbs and helped keep motor current in a safer range.

Cosmetic and ergonomic tweaks

I relocated the display or swapped to a more ergonomic throttle to match my handlebars. Small changes like repositioning the battery or rerouting cables improved balance and handling.

Comparing this Tongsheng Kit to Alternatives

I weighed this kit against hub motors and other mid-drive systems I’d ridden.

Versus rear hub motors

Mid-drives like the Tongsheng preserve handling better and make climbing more efficient by leveraging the bike’s gears. However, hub motors can be simpler to install and sometimes cheaper for basic commuter needs.

Versus other mid-drive brands

Compared with some higher-end mid-drive systems, the Tongsheng offers a compelling balance of cost and features, especially with its torque sensor. Premium systems may provide higher power or refined software, but at a steeper price.

Who This Kit Is Best For

I recommend this kit for riders who want performance and a natural pedaling feel without buying a full e-bike.

Ideal users

• Do-it-yourself mechanically confident cyclists
• Riders who prioritize natural pedaling assistance for long rides or hilly terrain
• People with compatible bikes (68–73mm BB) looking to maintain sporty handling

Not ideal for

• Absolute beginners who have never done bike maintenance
• Frames with incompatible bottom brackets or complex integrated systems
• Riders seeking a simple plug-and-play rear hub conversion

Pros and Cons I Experienced

Summarizing the highs and lows helps me decide whether the kit meets different needs.

Pros	Cons
Natural, proportional assistance thanks to torque sensor	Installation requires mechanical skill and tools
Mid-drive position improves balance and climbing	Increased drivetrain wear compared to unassisted riding
Flexible battery options for range tailoring	Some variants require sourcing battery separately
Quiet and efficient relative to many hub motors	Display and controller options vary by seller; documentation can be sparse
Works with bike gearing for better hill performance	May exceed local legal limits without tuning or limiting

I found the pros outweighed the cons for my use case, but your priorities might lead to a different conclusion.

Real-World Use Cases I Tried

I tested the kit across different scenarios and report what worked well.

Commuting and city riding

The torque-sensed assist made stop-and-go traffic comfortable, with the motor responding smoothly when accelerating from lights. The mid-drive layout felt balanced with a battery mounted low on the frame or a rear rack.

Trail and mountain riding

On singletrack and steeper trails, the motor’s ability to use low gears extended my range and made long climbs manageable. I was conscious of added stress on the chain and cassette and adjusted maintenance accordingly.

Cargo and tricycle applications

The kit’s strong torque output is suitable for heavier loads and tricycle conversions. The motor’s scalable assistance allows for controlled acceleration even with cargo, though I ensured brakes and frame reinforcements were adequate.

Cost Considerations and Value

I compared cost-effectiveness and long-term value.

Upfront cost

The kit itself can be a mid-range spend compared to basic hub kits. Adding a quality battery increases cost but is a worthwhile investment for range and safety.

Long-term value

A successful conversion can save money versus buying a new e-bike, especially if I already liked my bike’s geometry. Factor in drivetrain replacements and periodic maintenance when calculating lifetime cost.

Tips I Learned During My Build

I compiled practical tips that saved me time and frustration.

• Test-fit everything before applying thread locker.
• Photograph wiring connections before disassembly for easier reassembly.
• Use a torque wrench to avoid overtightening and damaging components.
• Buy a battery with a reputable BMS and sufficient capacity for your typical rides.
• Keep spare connectors and fuses on hand for troubleshooting.
• Consider upgrading brake pads and rotors if you plan to ride fast or carry cargo.

These small practices made installation smoother and reduced downtime later.

Final Thoughts and My Recommendation

I enjoyed how the Tongsheng Mid-Drive Kit with Battery(Optional) 48V500W Torque Sensored Drive Motor DIY Ebike Conversion Kit for 68-73MM Bottom Bracket Mountain Bike,Citybike,Tricycle transformed my bike. The torque sensing and mid-drive arrangement created a natural and powerful ride that felt like a polished e-bike rather than a retrofit.

If you’re mechanically inclined, want realistic pedal assistance, and have a compatible frame, this kit is a strong choice. Make sure to budget for a high-quality battery and anticipate slightly higher drivetrain maintenance. For riders who want a simple swap or who lack mechanical confidence, a hub motor or a factory-built e-bike may be easier. For me, the Tongsheng kit hit the sweet spot between performance and value, and I enjoyed the process of turning my bike into a versatile electric machine.

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