The Grin All-Axle Hub Motor

The Grin All-Axle hub is a direct-drive motor series we designed to be universally compatible with all the varieties of quick-release and thru-axle mounting standards that exist in the bike world these days. It solves the compatibility problem between hub motors and modern bicycle frames, it provides the benefits of direct drive without the traditional heft, and it simplifies installation with integrated torque arms and torque sensors. 

Features

• Both FRONT and REAR models available
• Both regular width (27mm) and Fatbike models (45mm) available.  
• Lightweight 4.0 kg for regular / 6.0 kg for fabike, vs ~6kg and ~9kg for comparable generic DD motor
• 0.35mm Laminations for low motor drag when pedaling unassisted
• Integrated Torque Arm with secure frame mounting clamp
• Uses 32 Spoke Holes for vastly more in stock rim options
• Min 18mm Disk Caliper Clearance fits most (but not all) calipers without spacers
• Statorade Compatible with side cover injection port
• Available in both metallic silver and black anodized finish
• Designed and Assembled in Canada

Rear Specific

• Built-In Torque and PAS Sensor. No need for bottom bracket torque or cadence sensors
• Support both Shimano HG and SRAM XDR cassettes, with XDR for wide range 11-12 speed
• Fits Most Rear Dropout Standards (135mm quick release, 12x142 Thru Axle, 12x148 Boost Thru Axle, 170&190 Fatbike, 177&197 Thru-Axle Fatbike)

Front Specific

• Fits Almost All Front Fork Standards (100mm and 135mm Quick Release, 12mm, 15mm, 15mm Boost, and 15mm x 150 Thru-Axle)
• Compatible with Single Side Installation on many trike and quad vehicles

Technical Specifications

 

 

	Regular (27mm) Model			Fat (45mm) Model
	Slow (8T)	Standard (6T)	Fast (5T)	Slow (5T)	Standard (4T)
kV	7.5 rpm/V	10.0 rpm/V	12.0 rpm/V	7.2 rpm/V	9.0 rpm /V
Phase to Phase Resistance	268 mΩ	145 mΩ	100 mΩ	155 mΩ	102 mΩ
Phase to Phase Inductance	680 uH	380 uH	260 uH	-- uH	-- uH
Hysteresis Drag Torque	0.6 Nm			1.0 Nm
Eddie Current Drag Torque	0.0005 Nm/rpm			0.0008 Nm/rpm
Spoke Flange Diameter	214 mm			214 mm
Flange Spacing	49 mm			67 mm
Magnetic Pole Pairs	23			23
Motor Weight	4.05 kg (8.9 lb) Front / 4.30 kg (9.4 lb) Rear			6.0 kg (13.2 lb) Front / 6.2 kg (13.6 lb) Rear

User Manuals

 

 

Motor Speed

The Standard Grin All-Axle Motor is currently produced with three different windings; a slow 8 turn stator, a standard 6 turn stator, and a fast 5 turn stator. Ignoring potential limitations of your motor controller, all three motor winds are capable of producing exactly the same torque and power outputs, so the recommended motor model depends on your desired vehicle speed. The faster wind motors are more appropriate for small wheel diameters and/or lower battery voltages, while the slower motor winds are more common with larger wheel sizes and higher battery voltages.

The following table shows the unloaded speed of each motor winding at common battery voltages in 20" 26", and 29" (700c) wheel sizes.

Unloaded Speeds of All-Axle motors (27mm Stator)

	Slow 8T Wind (7.5 rpm/V)			Standard 6T Wind (10 rpm/V)			Fast 5T Wind (12 rpm/V)
	20” Wheel	26” Wheel	29” Wheel	20” Wheel	26” Wheel	29” Wheel	20” Wheel	26” Wheel	29” Wheel
36V Battery	26 kph	34 kph	37 kph	34 kph	45 kph	50 kph	41 kph	54 kph	60 kph
48V Battery	34 kph	45 kph	50 kph	46 kph	60 kph	67 kph	55 kph	72 kph	80 kph
52V Battery	37 kph	49 kph	54 kph	50 kph	65 kph	72 kph	60 kph	78 kph	87 kph
72V Battery	52 kph	67 kph	75 kph	69 kph	90 kph	100 kph	83 kph	108 kph	120 kph

 

The 45mm Fatbike Motors are available in two winding options, a slow 5T stator and standard 4T stator. In general, the bottleneck for power and torque capability of these larger motors will be the phase current limit of the Baserunner or Phaserunner motor controller. This table shows the unloaded speed of both fatbike motor windings at common battery voltages in 20" 26", and 29" (700c) wheel sizes.

Unloaded Speeds of Fat All-Axle motors (45mm Stator)

	Slow 5T Wind (7.2 rpm/V)			Standard 4T Wind (9 rpm/V)
	20” Wheel	26” Wheel	29” Wheel	20” Wheel	26” Wheel	29” Wheel
36V Battery	24 kph	31 kph	35 kph	30 kph	39 kph	44 kph
48V Battery	32 kph	42 kph	46 kph	40 kph	53 kph	58 kph
52V Battery	35 kph	45 kph	50 kph	43 kph	56 kph	62 kph
72V Battery	48 kph	62 kph	69kph	60 kph	78 kph	87 kph

The top speed under any kind of load is going to be less than this value, and we recommend using our motor simulator for exact performance details of any given combination of motor, battery voltage, and controller model.

 

For a more detailed understanding we recommend using our motor simulator or trip simulator applications to properly predict the capability of this motor in any specific usage scenario.