Mechanical internal gears are essential components in a vast array of machinery, from complex industrial equipment to smaller, precise mechanisms. Their unique design offers advantages in compactness and torque transfer, making them a critical choice for engineers and manufacturers. Selecting the appropriate internal gear is vital for ensuring optimal performance, longevity, and efficiency of any system.
- Thickness 6MM. The inner gear ring is: 1 mode 78 gear. Heavy-duty support/crane turret ring gear.
- Material: powder alloy. Outer diameter 89.9MM.
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- Durability Material: Crafted with steel reinforced nylon construction for enhanced strength and long lasting performance in electric bike applications
- Bearing Integration: Equipped with pre installed 608 bearings for smooth rotation and reduced friction during motor use and extending the lifespan of your motor.
- Universal Compatibility: Fit replacement gear set for Bafang 250W hub motors, with a 38mm (1.5") diameter and 12mm (0.47") thickness for precise fit.
- Precision 36-Tooth Design: Engineered for optimal gear engagement, reducing wear and tear while maintaining efficient torque transfer in e-bike systems.
- Complete Repair Kit: Includes 3 gears per pack, providing multiple replacements for maintenance or upgrades (weight: 155g).
- 100% Brand new and high quality.
- Material:Plastic. Quantity:75pcs
- 75 kinds of parts and accessories in just one package, which makes it a perfect choice for laboratories, science education, and DIY models.
- The plastic includes crown gear, single gear, double gear, worm gear, belts and other transmission parts. And all the display pictures were taken in kind.
- [NOISE REDUCTION TECHNOLOGY] The specially designed nylon and stainless steel teeth significantly reduce operational noise, providing a smoother and quieter ride.
- [ MATERIALS] Crafted from a combination of nylon and stainless steel, these gears are built to withstand wear and tear, ensuring long-lasting performance for your motor.
- [OPTIMAL PERFORMANCE] Featuring 36 teeth, these gears enhance the efficiency of your geared motor, making them suitable for various applications in electric biking.
- [SIZING REMINDER] Please check your specific gear requirements rather than relying solely on standard sizing charts.
- Product Packaging: This product contains 200 gears, a generous quantity to provide ample choices for your DIY projects and meet your needs.
- Comprehensive Gear Set: This 200-piece plastic gear set includes gears of various sizes, providing everything you need for your DIY model toy gear kit projects.
- Versatile Applications: These gears are perfect for remote control cars, robots, and other mechanical projects, designed to satisfy the hands-on entertainment needs of enthusiasts and offer endless creative possibilities.
- Product Materials: These gears are made of durable plastic, lightweight yet sturdy, ensuring reliable performance in a variety of applications, from small motor gears to complex mechanical components.
- Multiple Sizes: The gear set features bore diameters ranging from 0.8 mm to 3 mm, accommodating different shaft sizes, making it suitable for various projects and ensuring compatibility with a wide range of components.
- The Gear Package included: spindle, single/double crown gear, pulley, rack, bevel gear, copper gear, bushings, axles, tires, rubber bands and so on, more accessories that you need for diy toy cars/robots/motors.
- Axle length of 30mm, 50mm, 70mm, 100mm, shaft diameter is 2mm, 2pcs / kind, for a total of 8 Pcs
- Five wheel wheels: outer diameter 30mm, inner hole 2mm，for a total of 4 Pcs
- The characteristics of gear: 36MM yellow 2mm hole belt wheel, rack, four-wheel drive, 28 tooth 2mm hole Fan teeth and 30-100mm gear axle, five wheel wheel diameter 30mm!Multi-uses, you can use it to fix the toys,Great for diy science and small production...
- Most gear is 2mm aperture (tight or loose), in addition to one 81.5A spindle hole is 1.5mm, there are 2 crown is 2.5mm, there are 1 crown gear C303A is 3mm, one 15 teeth 2.3mm hole and 3.17mm hole.
- Module: 0.5
- Quantity:Approx. 58PCS（Note：Due to the presence of small gears, there may be slight discrepancies in the product quantity.）
- Note：This is small gear set,before purchasing,please check the product size to ensure it meets your needs
- Diameter:Gear diameter:From 3mm/0.11" to 28mm/1.1" , Gear Inner hole diameter: 1.9mm, 2.0mm, 2.55mm, 3mm
- Application:58PCS Plastic gears module 0.5 for DC motor,DIY model toys,RC car,robot gear replacement (Note:Due to the large number of gears, some styles or quantity may be slightly different )
- Core Drive Support: 10 Tooth Gear copper pinion is made for motor gears in small mechanical assemblies, helping transfer power in remote control vehicles, aircraft gear systems, and other compact models that need steady meshing and controlled movement
- Copper Material: This Copper Pinion is built from copper and can be used for DIY model making, small production projects, and science experiments, giving hobby builders a gear option for compact mechanical designs and assembly testing
- Small Modulus Fit: Measuring 0.19 x 0.19 x 0.19 in, this Small Modulus Gear is sized for tight spaces in micro motors and miniature mechanisms, making it easier to match gear spacing and align parts in small devices
- DIY Project Use: Motor gears are practical for DIY car models, mechanical model builds, and product design tasks, supporting stable motion and a smoother control feel during assembly, testing, and small-scale hobby projects
- 20 Piece Pack: Each package includes 20 x copper pinions, providing a convenient supply for replacements, upgrades, or multiple builds, and the 13.00 g gross weight makes the set easy to store, carry, and organize for hobby work
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Last update on 2026-09-01 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Mechanical Internal Gears
Understanding Internal Gear Types
Internal gears, where the teeth are on the inner surface of a ring, come in several primary forms. Spur internal gears are the most common, offering simple design and high efficiency. Helical internal gears provide smoother operation and higher load-carrying capacity due to their angled teeth, which engage gradually. Bevel internal gears are used for right-angle power transmission. Understanding the application's torque, speed, and alignment needs will dictate the most suitable type.
Key Material Considerations
The material of an internal gear significantly impacts its durability, wear resistance, and operating temperature. Common materials include various steel alloys (like carbon steel and alloy steel) which offer excellent strength and toughness. For environments requiring corrosion resistance, stainless steel is a strong option. Some applications may benefit from non-metallic materials like certain plastics or composites, especially where weight or electrical insulation is a concern. Always consider the operating environment and load requirements when choosing a material.
Tooth Profile and Pitch
The tooth profile, most commonly the involute profile, determines how the teeth mesh and transmit power. The pressure angle, typically 20 degrees, affects the gear's efficiency and load-carrying capability. Gear pitch, which defines the size and spacing of the teeth, is crucial for matching gears to create the correct gear ratio and power transmission. Fine pitches are used for smaller, precision applications, while coarse pitches are for heavier-duty industrial uses. Ensure the pitch and profile are compatible with the mating gear.
Lubrication and Maintenance Needs
Proper lubrication is critical for the longevity and performance of any gear system, including those with internal gears. The type of lubricant (oil or grease) and its viscosity will depend on the operating speed, temperature, and load. Regular inspection for wear, damage, and adequate lubrication levels is essential. Understanding the maintenance requirements associated with different gear types and materials will help prevent premature failure and ensure consistent operation.
Choosing the Right Size and Bore
The physical dimensions of an internal gear, including its outer diameter, face width, and bore diameter, must be carefully considered to fit within the available space and connect to the driving or driven shaft. The bore size needs to be precise for a secure fit, often requiring keyways or splines for torque transmission. Ensure that the chosen gear's dimensions accommodate the housing, shaft, and any associated components without interference.