So I decided to open all these motors up and try to compare them. I don’t know too much about magnet physics, so I won’t comment explicitly on the curvature or lack thereof of the magnets on these motors, but the other stuff I have more experience with.
All 3 of the motors are the most up-to-date versions. They all claim to be 170kv
New Flipsky 6374
The newer flipsky 6374 are the first motor actually designed and made by flipsky themselves. After doing a GB on them, I am probably the first person to get the 170kv version and try them out
General characteristics
The motor seems to be very quiet and has a smooth start in HFI with less cogging than other motors. It doesn’t have a huge kick like maytechs, perhaps more comparable to SK3s.
Can Weight: 370g
Stator weight: 573g
Approx Assembled weight: 950g
Stator length (Edge to edge, not including tallest winding): 45mm
Stator Diameter: 53mm
Internals
Magnet retention
No dual retention rings like other motors, but a large amount of epoxy.
Hall Sensor PCB
The sensors are embedded in the stator, and they actually have epoxy supporting the PCB and wires, something missing on other motors. There isn’t insulation on the top of the 3 pin sensors though which is a shame as there is on the 5 pin connection.
Shaft design
Retained with 2 grub screws under a large amount of epoxy/loctite. Perhaps impractical if you want to replace the shaft, but the shaft is machined with holes for the grub screws so they’re not just pressed onto the shaft like the older jointechs. Stepped design is a good thing for compatibility and strength, currently not available on other motors without requesting modifications. Please note this will mean some of the extra can weight is in the shaft for the flipsky motors, but irregardless its still a higher thermal mass for an 8mm shaft motor.
Can design
The can sits flush with the stator and has no air-gaps at the back, creating a more sealed design. Its also longer than the maytech can, but it does have a total length of 74mm.
Stator
Yes, the stator is actually larger than a maytech stator. Its heavier too, even though the wires are slightly thinner and the shaft hole is larger.
Maytech MTO6374-HA-C
Maytech has recently been advertising their newer 6374 motors as battle hardened, so I decided to pick some up
General characteristics
Maytechs are classicly coggy, but have a real kick on startup. They’re also pretty loud but I like the noise
Can Weight: 311g
Stator weight: 553g
Approx Assembled weight: 870g
Stator length (Edge to edge, not including tallest winding): 40mm
Stator Diameter: 53mm
Internals
Magnet retention
Large bottom-sided retention ring, epoxy on the motors top to bottom, but only filling the gaps roughly halfway.
Hall Sensor PCB
The sensors sit just above the stator, but aren’t actually supported directly which is a shame. There is epoxy retaining the wires in the stator and at the bottom of the motor. There isn’t insulation, but the 5 pin connections are spread far apart. The 3 pin sensors however are much closer and aren’t epoxy coated for insulation
Shaft design
8mm through shaft with excellent retention via a small rounded key to prevent spinning in addition to accessible dual grub screws.
Can design
The can sits flush with the stator and has no air-gaps at the back, creating a more sealed design. It has a nipple on the back which can make it weird to dual mount on some trucks but the water and dust resistance is good. Its not possible to make a proper seal as when the motors spin things can always creep in.
Stator
40mm in length, actually suprisingly the same as the C6374s.
Dickyho C6374 / Ali motors / $40 Shitter motors
Cheap and cheerful, sometimes as low as $35 you can get this on ebay or aliexpress. They’re not actually 74mm in length, they’re a little shorter.
General characteristics
Smoother startup, and fairly quiet in FOC. Very “average”
Can Weight: 327g (10mm through shaft though)
Stator weight: 484g
Approx Assembled weight: 810g
Stator length (Edge to edge, not including tallest winding): 40mm
Stator Diameter: 53mm
Internals
Magnet retention
Shitty magnet glue only (Not pictured, all the ones I have are epoxied by myself)
Hall Sensor PCB
They’re below the stator. There isn’t any epoxy on the wires, there is also no temp sensor. Highly reccomend going sensorless with these, the phase cables are also very thin, which limits the motor to about 50 amps before they really get actually hot
Shaft design
10mm D shaped through shaft with only grub screws for retention with no recess to actually hold the shaft properly, although it is 10mm and epoxied to the can. Its impossible to find goddamn pulleys for this thing though, they only come in aluminum.
Can design
Its open on the back, so dust does get inside more easily. But in general its less of a problem than people make it out to be.
Stator
40mm in length, actually surprisingly the same as the Maytechs.
Full album of images including measurements
