Grin's rear all axle motor!

4.3kg (9.4lbs) for the rear motor is extremely impressive.
I'm going to have to pick one of these up.
 
Got mine a while back and finally getting it installed..

A few challenges, first was the rim option. could only get a thin 32 hole when i ordered it.. but was able to order a 650B wide profile rim.. so got a mullet going on with a GT Helion 9R...

Axle was then difficult to get thru the motor, had to work it with a round file and force it thru but that worked out...

Then my truing stand would not old a thru-axle properly so i had to true it from the bike frame... i have since ordered thru-axle adapter for my Park Tool TS-2 lol

Next issue was that this bike has a pivot in the swingarm that interferes with the torque arm mounting.... workaround was to use the kick stand lower bolt to secure an aluminum bar.. looks like it will work so far !

Now the last hurdle... the Grin All Axle motor has an L10 and a 6 pin Higo wire for the PAS.. however, the CA wants a 5 pin JST.... my motor did not include the extension, so i figured no problemo.. cut the wire and solder in an extension.. but woops... there are 6 wires in there...

i emailed Grin to ask, but it's that time of year and not getting a 24 hr reply.... if anyone happens to know what goes where.. please chime in !
 

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Ypedal said:
Got mine a while back and finally getting it installed..

A few challenges, first was the rim option. could only get a thin 32 hole when i ordered it.. but was able to order a 650B wide profile rim.. so got a mullet going on with a GT Helion 9R...

Axle was then difficult to get thru the motor, had to work it with a round file and force it thru but that worked out...

Then my truing stand would not old a thru-axle properly so i had to true it from the bike frame... i have since ordered thru-axle adapter for my Park Tool TS-2 lol

Next issue was that this bike has a pivot in the swingarm that interferes with the torque arm mounting.... workaround was to use the kick stand lower bolt to secure an aluminum bar.. looks like it will work so far !

Now the last hurdle... the Grin All Axle motor has an L10 and a 6 pin Higo wire for the PAS.. however, the CA wants a 5 pin JST.... my motor did not include the extension, so i figured no problemo.. cut the wire and solder in an extension.. but woops... there are 6 wires in there...

i emailed Grin to ask, but it's that time of year and not getting a 24 hr reply.... if anyone happens to know what goes where.. please chime in !
Click to expand...
Regarding the axle, is there a chance their machining work wasn't good? Or something else
 
I recall that even though it's a direct drive, it was specifically configured to have low cogging. The idle drag is low enough when only pedaling, that its almost indiscernable..

This means no clutch to go out, such as those found on common geared hubmotors.

Also, geared hubs have a poor heat-shedding path, so this motor benefits significantly from adding ferro-fluid, which doubles the acceptable acceleration amps.

I think this design is a good idea, and I think it will find many happy customers.
 
Last edited:
Ypedal said:
Got mine a while back and finally getting it installed..

A few challenges, first was the rim option. could only get a thin 32 hole when i ordered it.. but was able to order a 650B wide profile rim.. so got a mullet going on with a GT Helion 9R...

Axle was then difficult to get thru the motor, had to work it with a round file and force it thru but that worked out...

Then my truing stand would not old a thru-axle properly so i had to true it from the bike frame... i have since ordered thru-axle adapter for my Park Tool TS-2 lol

Next issue was that this bike has a pivot in the swingarm that interferes with the torque arm mounting.... workaround was to use the kick stand lower bolt to secure an aluminum bar.. looks like it will work so far !

Now the last hurdle... the Grin All Axle motor has an L10 and a 6 pin Higo wire for the PAS.. however, the CA wants a 5 pin JST.... my motor did not include the extension, so i figured no problemo.. cut the wire and solder in an extension.. but woops... there are 6 wires in there...

i emailed Grin to ask, but it's that time of year and not getting a 24 hr reply.... if anyone happens to know what goes where.. please chime in !
Click to expand...

Don't you need to anchor the torque arm to the seat stay since that's where the axle is mounted?
 
Does anyone know how much torque this motor has. As in apples to apples torque compared with other motors that generally start out at 30 Nm and up. Grin is a bit elusive and quoted it around 0.45 Nm, but for something that's 1200W peak w/o Statorade I'm guessing it would generate between 30-60 Nm? 60 would be nice...30 I don't think I would be interested.
 
How many NM at what RPM and at what voltage and amperage?

Here is a scenario where you could realistically produce 95nm from a stall.
Motor Simulator - Tools

Possibly grin has a typo somewhere; 0.5 Nm would be an appropriate torque rating for maybe a 10w stepper motor. :)

1692296759010.png
 
neptronix said:
How many NM at what RPM and at what voltage and amperage?

Here is a scenario where you could realistically produce 95nm from a stall.
Motor Simulator - Tools

Possibly grin has a typo somewhere; 0.5 Nm would be an appropriate torque rating for maybe a 10w stepper motor. :)

View attachment 338241
Click to expand...

That's a lot of torque for a direct drive. If climbing between 5-10 MPH, it really is 68-82 Nm? That's pretty good.

Not to play devil's advocate or anything but how long can a direct drive actually keep up the torque and power at 5-8 mph up something on dirt that's an 8-12% average grade for several hundred feet (let's say 400 feet to the top, sounds easy but 400 feet is a lot of dirt to climb). I know a geared hub drive can do it, and the power does not fade. Can this particular direct drive do it? And if yes, what internally sets it apart from the others that bog down? In your opinion can this motor maintain torque and power uphill as well as a Bafang 500W geared hub drive?
 
Well, personally i've found the simulator ( click the link, i've made it easy for you by pre-filling the data ) very accurate so i'd say, take my link, increase the grade to 10% and see what happens. You will want to adjust the power to meet your scenario of course ( in my link, i'm running fairly high power )

See how it works on the condition you're looking for.

It should blow away your 500w geared hub pretty easily even though it's one of the smaller DD hubs. Geared motors are far from the most powerful thing you can put on a bike. :)
 
Bafang G60 500W Geared Hub Drive

10% grade, peak torque 45 Nm up to 12 mph @400-500W.



Grin V2 All-Axle Direct Drive 1000W Max

10% grade, peak torque 38 Nm up to 11 mph @350-400W.



Surprisingly similar. Have to give the direct drive credit actually for being so similar if it's 500W nominal and 1000W peak; I would have guessed that the peak torque for 500W nominal would have been more like 25 Nm. BTW the Bafang G62 that they sell as a fat-bike kit on Amazon for $400 is about the same as the G60, 46 Nm peak torque to 13 mph at a little higher rpm of 500-550W. They say the peak torque is 65-80 Nm for the G60 but maybe that's for 750W 'nominal' since some list as 500W nominal and some 750W.

The Bafang FM and RM G020 500W geared hub drives (not in the simulator) are selling as complete laced wheel kits w/o battery for $300 now. I have the FM version; they list peak torque for both of those older motors as between 45-65 Nm which is very consistent with the numbers above. Now I know you guys are very goo goo gaa gaa over Grin, but you have to admit that if these numbers are actually correct offroad on fire road or singletrack climbs, most other variables being equal besides the battery, controller, etc. the Bafang slightly outperforms at much, much less cost. No, the Grin does not blow it away uphill. Maybe with some controller/display manipulation it could do better. One could argue the same for the Bafang kit as well with a KT LCD as standard display. The climbing prowess of the two motors are about the same. Cost is not the same.

For me, major issue is buying yet another 135mm frame to put a G020 rear hub drive in compared with a 142mm frame for the Grin (my current frame has been through the mill and really should be donated or trashed later). Other than that frame issue it's a no-brainer for the Bafang geared motor. Assuming someone is looking to climb hills of course.
 
I was not aware we were talking about the G60 motor instead of an ordinary 500w bafang motor.

The problem here is that the grin motor is being under-driven in this scenario and is outside of it's efficiency curve.
It would be a very bad idea to drive it on 36v/20a only. You're lugging it.

Try this scenario. You're going up the hill at 23mph now. You can do that for 8.5 minutes until the motor melts..
Motor Simulator - Tools

You can put ferrofluid inside the grin motor to extend that heat buffer but you can't do that with the bafang.

The bafang G60 is more like a 1000w motor. It's intended for a fatbike frame ( extremely wide axle ) and is fairly comparable.
The grin can work on a 135mm/142mm/148mm axle.
 
thepronghorn said:
Don't you need to anchor the torque arm to the seat stay since that's where the axle is mounted?
Click to expand...
I was thinking the same thing, with the anchor point being on the other side of the pivot. Seems like it will rotate the axle/motor when the suspension is active, but maybe that doesn't matter with a thru axle, as long as it prevents it from totally spinning.
 
Ypedal said:
Got mine a while back and finally getting it installed
Click to expand...
The drawings and photos Grin provides are inadequate. Can you answer some questions?

I have an All-Axle front motor and a GMAC rear motor from Grin, and both permit multiple mounting angles for the torque arm relative to the motor cable - in fact, the torque arm can be mounted at several positions through a full 360 degrees around the axle.

It appears that the All-Axle rear motor torque arm will only attach to the motor in one orientation relative to the cable - that is 'cable pointing down, torque arm pointing forward'. Is this correct? If not, can you say more about how it mounts?
 
Just to see what my DIY mid-drive could do on the graph...they don't have my controller of course on there so I selected the very top one, a 20 AMP, and did a 35V 16.5 Ah battery even though mine is 48V. The rest should fairly accurate. Double chain with 2.75 : 1 reduction.


Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...
ebikes.ca ebikes.ca

80 Nm torque up to maybe 6.5 mph at 450W. Torque curve drops off faster than for a hub drive. And that's OK. If it's a 10% incline, 6 mph is really not bad on dirt especially if it's tight singletrack.

If you are interested: fastest I've done on a 500W hub drive (at least I think it's the fastest), 10% singletrack grade with obstacles, about 400 foot climb was 8.2 MPH average. That is exactly the same time up the same section as a semi-pro in the area did with a normal human-powered bike. Yes, he knows how to climb.
 
I'm considering the possibility of ordering two of these as side motors in the 5T wind configuration for a tadpole trike, and running each at 144V and 5kW peak for short periods(< 20 seconds at a time). Once top speed is reached, I will only need about 1 kW continuous out of them. There would be one Grin for each front wheel, with a 4T wind Leafbike 1500W in the rear wheel also at 144V, and pushing 10 kW peak.

The idea would be to build something with AWD weighing in around 150 lbs that can accelerate faster than most cars and top out around 115 mph, but I have no idea what these Grin All-Axle motors can really handle.
 
This motor is starting to look interesting. Seems that with the 0.35mm laminations, it would be at least as efficient as my Leaf, and I'm guessing it could take 4kW-5kW or more for short bursts of acceleration. But, the couple of things that I really like are, the ability to use a quick release axle and skewers with my current frame, which would make flat repairs while on a ride a possibility; and the paired spoke holes for lacing my 24" rim radially.
Being able to use a cassette is nice, although I never shift anyway. But as long as it's serviceable (I wore out one freewheel, but that's an easier replacement than replacing a freehub), seems like a step in the right direction.
 
E-HP said:
This motor is starting to look interesting. Seems that with the 0.35mm laminations, it would be at least as efficient as my Leaf, and I'm guessing it could take 4kW-5kW or more for short bursts of acceleration. But, the couple of things that I really like are, the ability to use a quick release axle and skewers with my current frame, which would make flat repairs while on a ride a possibility; and the paired spoke holes for lacing my 24" rim radially.
Being able to use a cassette is nice, although I never shift anyway. But as long as it's serviceable (I wore out one freewheel, but that's an easier replacement than replacing a freehub), seems like a step in the right direction.
Click to expand...

It's rated at 500W and you are going to put 5000W through it?
 
richj8990 said:
It's rated at 500W and you are going to put 5000W through it?
Click to expand...
I only need to do so for about 15-20 seconds at a time. I'll be at 110 mph on flat ground by the time that has elapsed, considering there will be another Grin motor running the same input and a Leafbike running 10 kW peak.

I don't know if the Grin can handle 5 kW or not. Perhaps it could only do 2 kW peak, even with ferrofluid? Even so, that would still be quite usable. Temperature sensors with the CA3 set to dial the power back to prevent overheating will be a necessity.
 
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