kPa Research
1 µW
This article serves as "The" datasheet for Big Block motors, with an in-depth look at the LMX 60mm. The information below may or may not be true depending on the actual manufacturer and date of your motor. You have been warned.
Electrical details:
-Type: BLDC inrunner
-Rated output power (30min): 3100 W
-Rated peak output power (60sec): 6300 W
-Absolute peak output power: 20 kW+? (
)
-Phase wire cross section: 5mm2
-Temperature sensor: KTY84
-Max motor temp: 135 °C
-Rotor type & magnet height: SPM, 60mm
-Stator laminations: 0.35mm
-Hall sensor angle: 60°
-Pole pairs: 4
-kV: 69rpm/volt
-Phase resistance: 0.0255 Ohm
-Inductance d: 82.99 uH
-Inductance q: 126.26 uH
-Flux linkage: 0.0319 Wb
Compatible controllers:
-Nucular 6F/12F/24F (FOC)
-Vesc (FOC)
-Infineon 12F?
-Kelly KBS72181 spare controller from LMX Bikes
-Sensorless controllers
-?
This motor (and some other GNG/BHT variants) is notoriously picky about controllers if you want to run it with hall sensors, the reason being noisy hall signals from the motor. It is suspected that the SPM rotor produces a non-ideal magnetic field for the hall sensors. Potential fixes include replacing the rotor with an IPM one, installing an external encoder or hall sensors, or trying to fix the hall output with diodes like in this thread: Kelly KLS7230 + LMX. Swapping the existing hall sensors to ones with higher gauss point might help too, as maitilupas told here: LMX Motor - Kelly Controller - Hall Problem?. At the top you can also see a picture of the oscilloscope output the hall sensors give.
Nucular runs it great even with sensors due to supporting hall filtering (Nucular even enables it automatically after auto-setup). Some users have tried Kelly KBS series controllers with the same stuttering / sync loss problems so LMX might have some secret sauce in their controller configs. There should be no problems running this motor in sensorless mode.
Mechanical details:
-Weight: 5.2 kg
-Dimensions: see mechanical drawing
-Bearings: SKF Explorer
-Front cover bearing size: 6203-2RSH
-Sprocket key: 4 x 4 x 12mm
-Housing & endcap material: soft chinese aluminium (keep in mind while tightening bolts) (stator can be pressed out if you want to machine your own motor housing: Selfmade E-Hardtail (Just have a look ;))
-Housing can be rotated
Recommended bolt tightening torques:
M8 bolts: 8 Nm
M5 sprocket bolt: 5 Nm
Motor mount 3D-models:
These have been printed by JLCPCB and they fit on the motor just about perfect, note that you need size M5 x 115mm housing bolts for the mount that goes on the back cover. These are hard to find but if you end up the usual eBay china special route, make sure to order some extras because half of what i ordered arrived bent lol.
Since you probably won't be using 3D-printed mounts i suggest you make some clearance for a few layers of paint also.
1drv.ms
Sprocket info:
Available from LMX: 219H 14T & 12T noise-cancelling (Jira Service Management)
Available from SenLi: 219H 12T (https://shorturl.at/opslb select correct axle width)
-Keep in mind that the chainline probably won't be the same between different suppliers.
-Motor axle keyway: 4 x 4 x 12mm
-Noise-cancelling 12T sprocket from LMX has o-rings on both side of the teeth to decrease noise output. 14T (or larger) naturally makes less noise. The o-rings wear much faster than the sprocket itself so spares are needed if you want to maintain the noise level. Correct size is 18 x 2,5mm (for example O-ring (ID x cross,mm) 18 x 2,5 DIN 3770, EU origin, variable pack, material | eBay), 19mm ID should work too but it could be a bit too loose. For better durability you could opt for higher toughness like NBR 90 ShA.
*If you have any information to add or spot any mistakes, feel free to send a message or comment below.*
Changelog:
22.9.2024
-Added sprocket info
-Updated dimensions on the mechanical drawing
5.2.2025
-Fixed a wrong measurement on the technical drawing, motor mount files not affected
11.2.2025
-Added information on hall sensor output
Electrical details:
-Type: BLDC inrunner
-Rated output power (30min): 3100 W
-Rated peak output power (60sec): 6300 W
-Absolute peak output power: 20 kW+? (
-Phase wire cross section: 5mm2
-Temperature sensor: KTY84
-Max motor temp: 135 °C
-Rotor type & magnet height: SPM, 60mm
-Stator laminations: 0.35mm
-Hall sensor angle: 60°
-Pole pairs: 4
-kV: 69rpm/volt
-Phase resistance: 0.0255 Ohm
-Inductance d: 82.99 uH
-Inductance q: 126.26 uH
-Flux linkage: 0.0319 Wb
Compatible controllers:
-Nucular 6F/12F/24F (FOC)
-Vesc (FOC)
-Infineon 12F?
-Kelly KBS72181 spare controller from LMX Bikes
-Sensorless controllers
-?
This motor (and some other GNG/BHT variants) is notoriously picky about controllers if you want to run it with hall sensors, the reason being noisy hall signals from the motor. It is suspected that the SPM rotor produces a non-ideal magnetic field for the hall sensors. Potential fixes include replacing the rotor with an IPM one, installing an external encoder or hall sensors, or trying to fix the hall output with diodes like in this thread: Kelly KLS7230 + LMX. Swapping the existing hall sensors to ones with higher gauss point might help too, as maitilupas told here: LMX Motor - Kelly Controller - Hall Problem?. At the top you can also see a picture of the oscilloscope output the hall sensors give.
Nucular runs it great even with sensors due to supporting hall filtering (Nucular even enables it automatically after auto-setup). Some users have tried Kelly KBS series controllers with the same stuttering / sync loss problems so LMX might have some secret sauce in their controller configs. There should be no problems running this motor in sensorless mode.
Mechanical details:
-Weight: 5.2 kg
-Dimensions: see mechanical drawing
-Bearings: SKF Explorer
-Front cover bearing size: 6203-2RSH
-Sprocket key: 4 x 4 x 12mm
-Housing & endcap material: soft chinese aluminium (keep in mind while tightening bolts) (stator can be pressed out if you want to machine your own motor housing: Selfmade E-Hardtail (Just have a look ;))
-Housing can be rotated
Recommended bolt tightening torques:
M8 bolts: 8 Nm
M5 sprocket bolt: 5 Nm
Motor mount 3D-models:
These have been printed by JLCPCB and they fit on the motor just about perfect, note that you need size M5 x 115mm housing bolts for the mount that goes on the back cover. These are hard to find but if you end up the usual eBay china special route, make sure to order some extras because half of what i ordered arrived bent lol.
Since you probably won't be using 3D-printed mounts i suggest you make some clearance for a few layers of paint also.
Microsoft OneDrive
Sprocket info:
Available from LMX: 219H 14T & 12T noise-cancelling (Jira Service Management)
Available from SenLi: 219H 12T (https://shorturl.at/opslb select correct axle width)
-Keep in mind that the chainline probably won't be the same between different suppliers.
-Motor axle keyway: 4 x 4 x 12mm
-Noise-cancelling 12T sprocket from LMX has o-rings on both side of the teeth to decrease noise output. 14T (or larger) naturally makes less noise. The o-rings wear much faster than the sprocket itself so spares are needed if you want to maintain the noise level. Correct size is 18 x 2,5mm (for example O-ring (ID x cross,mm) 18 x 2,5 DIN 3770, EU origin, variable pack, material | eBay), 19mm ID should work too but it could be a bit too loose. For better durability you could opt for higher toughness like NBR 90 ShA.
*If you have any information to add or spot any mistakes, feel free to send a message or comment below.*
Changelog:
22.9.2024
-Added sprocket info
-Updated dimensions on the mechanical drawing
5.2.2025
-Fixed a wrong measurement on the technical drawing, motor mount files not affected
11.2.2025
-Added information on hall sensor output
Last edited:
