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Just 'Cuz Robotics

PREORDER JCR-4935 1000kV Battle Hardened Brushless Motor

PREORDER JCR-4935 1000kV Battle Hardened Brushless Motor

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Regular price $90.00
Regular price $95.00 Sale price $90.00
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Built For Combat From the Ground Up!


These newly designed motors are already paid for and in production, but there has been a lot of interest in them, so I am opening up a preorder round where you can buy in early for a discount. These motors are expected to arrive and ship out the second week of December 2023


Months of work have gone into making the most durable motor possible to fit into a beetleweight (or even bigger) combat robot, and this is the result. In larger weight class bots there are many modifications frequently made to motors to help them survive the rigors of combat. Boring out the motor to fit larger bearings, larger more durable shafts, removing circlips and set screws, and adding epoxy to the magnets all to battle harden these motors. Now for the first time ever, you can buy a motor off the shelf with all of these changes and more!

The JCR-4935 was designed with combat in mind from the ground up - this is not some hodgepodge of parts from different motors and separate machined components, it's a proper motor, tightly integrated and professionally balanced with every improvement reasonable in a mass-producible product. You can improve durability further with our custom shoulder bolts and clever blade mounting!

What's Included:
1X 4935 motor, combat-ready out of the box!
6X Alloy Steel M5 x 12mm flat head screws
4X Alloy Steel M5 x 10mm button head screws
4X 6mm diameter x 10mm length hardened steel dowel pins (these will be a slip fit with the top of the motor, and must press fit into blades or whatever else you are attaching on top).
This motor is intended to be mounted to a rigid robot frame component and as such does not come with a mounting plate or bracket. 



  • Dimensions: 49mm can diameter, 35.5mm can length
  • Stator Size: Roughly 40 x 12mm
  • Weight: 213 grams (7.5 oz, 0.47 lb)
  • KV: 1000kV (More options may be available in the future)
  • Peak Power: Over 700W measured on 3S (62 amps), even higher on 4S or more
  • Continuous Current: Measured 32A with 9 inch x 3/16" blade
  • Voltage: 3S-6S with appropriate ESCs
  • 6X M5 bolts for mounting to your robot frame, 4X M3 on 25mm circle as alternative 'compatibility' mounting
  • 4X M5 bolts and 4X 6mm dowel pin holes to attach weapons, gears, pulleys, or whatever else you can think of
  • 4140 Alloy steel 8mm billet flanged shaft, hardened to 46-48HRC
  • No circlips or set screws!
  • Super strong, curved neodymium magnets
  • Epoxied magnets for extra durability
  • High-temperature copper windings, 14AWG silicone wires rated to 200 C
  • Large 698 and 688 bearings to support the shaft, M5 button head bottom shaft attachment

3D Model Available Now!

See the Additional Info tab for more!

Additional Info

The specs are not precisely known due to this being a custom motor, but you should use a 50A or greater rated ESC and expect a continuous current draw of up to roughly 35 amps maximum at 3S. This has been tested and working with 70A BlHeli32 and AM32 ESCs, 45A Tekko45, and a few others.  More testing is still in the works.

A few prototype V1.0 motors were produced in time for the September 2023 NHRL event and two saw use in the beetleweight bot Subtraction. These motors had a couple of issues that are being resolved with a V1.3 redesign which is pictured in the renders above, and which you would be purchasing with this preorder. The last photo shows the V1 prototype V1.0 motors (no flanged shaft, no epoxied magnets, but otherwise very similar to V1.3).

Note: I am working on sourcing AM32 ESCs pre-programmed for weapon use with this motor. 

Actual current draw and torque are highly dependent on your exact ESC and configuration, battery, voltage, and loading.

Final pricing is still to be determined based on demand.


Warning: combat robots are not toys! They are extremely dangerous. Click here for a safety video.

Testing a robot with an active spinning weapon should never be done while maintaining a line of sight with the robot. Ideally, you should be testing inside an enclosed box or arena with at least 1/4" thick polycarbonate windows or top to see through, and 1/2” or thicker plywood or MDF construction. Operation (Including testing) outside of a suitable arena or test box could cause serious injury. By purchasing this product you acknowledge that you are responsible for the safe use of this product and that Team Just ‘Cuz Robotics or its employees are not liable for any injuries or damages.

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