AK70-9 V3.0 KV60 without driver vs AK80-9 V3.0 KV100 without driver

The AK70-9 V3.0 KV60 without driver has more peak torque (29.2 N·m against 22 N·m) and a higher torque constant (0.159 N·m/A against 0.095 N·m/A), draws less current at its rating (6.25 A against 12 A), and is narrower (89 mm against 98 mm). The AK80-9 V3.0 KV100 without driver has more continuous torque (9 N·m against 8.5 N·m), is lighter (490 g against 540 g) and shallower (38.5 mm against 49 mm), and turns faster at the output (390 RPM against 260 RPM).

The AK70-9 V3.0 KV60 without driver is US$447 and the AK80-9 V3.0 KV100 without driver is US$537. That is US$52.59 per rated N·m for the AK70-9 V3.0 KV60 without driver and US$59.67 per rated N·m for the AK80-9 V3.0 KV100 without driver.

Which to buy

Every published specification

AK70-9 V3.0 KV60 without driverAK80-9 V3.0 KV100 without driver
Reduction Ratio9:19:1
Rated Torque (N·m)8.59
OD (mm)8998
Weight (g)540490
Peak Torque (N·m)29.222
Rated Voltage (V)4848
Rated Speed (RPM)260390
No-Load Speed (RPM)320570
Rated Current (A)6.2512
Peak Current (A)23.828
Maximum Torque Density (N·m/kg)5444.9
Height (mm)4938.5
Backlash (arcmin)1815
Back Drive (N·m)0.80.51
Kv (RPM/V)60100
Kt (N·m/A)0.1590.095
Ke (V/kRPM)16.710
Phase to Phase Resistance (mΩ)475160
Phase to Phase Inductance (μH)408116
Rotor Inertia (g·cm²)450579
Motor Constant (N·m/√W)0.230.2387
Mechanical Time Constant (ms)1.70.725
Pole Pairs2121
Number of Slots2436
Winding TypeDeltaDelta
Number of Encoder21
Inner Loop Encoder TypeMagnetic EncoderMagnetic Encoder
Inner Ring Encoder Resolution14bit16bit
Outer Ring Encoder TypeMagnetic Encoder—
Outer Ring Encoder Resolution15bit—
CAN ConnectorA1257WR-S-4P—
UART ConnectorA1257WR-S-3PA1257WR-S-3P
Power ConnectorXT30PW-MXT30PW-M
Temperature SensorNTC MF51B 103F3950NTC MF51B 103F3950
Noise dB (65cm away the motor)5060
Basic Dynamic Load Rating Cr (N)18902760
Basic Static Load Rating C0r (N)21402810
Operation Ambient Temperature-20℃~50℃-20℃~50℃
Insulation LevelCC
Driving WayFOCFOC
ApplicationLegged Robot, Exoskeleton, AGVLegged Robot, Exoskeleton, AGV

Rows the two disagree on are marked; the figures are CubeMars'. To put any other two parts side by side, build your own comparison.