Failure rate (points) for Grin's all-axle rear hub motor, or, choosing a hub motor

[Mongo]

I'm considering converting a mid-drive bike I have to rear hub motor drive, and I can go 135mm O.L.D. bolt/QR or 148mm x 12mm thru-axle. The former would give me more motor vendor options, while the latter path would have to be via Grin. The wheel size would preferably be 650B/27.5", or 26" if necessary, with semi-knobby tires (along the lines of the Schwalbe Marathon MTB in 2.25"). with fenders. And, I want 9-speed cassette capability.

I only have limited hub motor experience, and that's with a RH212.

The intended use for the bike would be on mild incline paved/pea gravel rails to trails, ~50-75 miles per day assisted range, at ~12-15mph (for battery range conservation), but with short distance bursts of ~30mph tops to travel short distances off-trail to B&B/hotel/food locations. Rolling weight would be ~325lbs.

So why consider the Grinmotor? Is the convenience of the thru-axle, torque arm choices, and "all-in-one electronics" worth the rather lofty purchase price? Another negative may be that little/no troubleshooting or repair is possible on the Grin motor without delacing the rim - though maybe this doesn't matter, as I wouldn't be able to get repair parts anyway, away from home and all.

So what's the question? I guess it's, has anyone else considered the Grin hub and been put off by the reparability nuisance? Is there a particularly high failure point? It's also hard to shake the pricepoint - I could have primary and spare motors/wheels in other brands, compared to one Grin motor.

But ... there's something "technically sweet" about the Grin motor, and it might allow me to integrate a Rohloff-inspired torque arm idea I've had (a takeoff of the Rohloff OEM dropout torque containment).

Given the lowish speed, mild terrain, and longish range requirements, which hub motor path would you choose?

 

[neptronix]

I believe Grin has fixed their manufacturing process for that motor approximately a month ago.
We have at least 1 report on the forum of a motor being fixed under warranty and running great.

I got a bunk motor many months ago and have yet to send it in, just been too busy. It has a knock at high RPM and a halls issue.

Having to delace the motor is a pain in the ass but the weight and only needing to take one bolt off is great in my eyes.
I love being able to easily chuck my ebike into a car. With 2 big torque arms, that's always a lot more drama.
Some hub motors are heavy enough that they produce a counter pendulum effect when steering; All Axle is light enough that this effect is absent from the ride experience.

RH212 is practically 2x the motor, torque output wise. If you have mild terrain and lowish continuous speeds ( < 35mph ), the All Axle would be great.

 

[chuyskywalker]

We have at least 1 report on the forum of a motor being fixed under warranty and running great.

That's me!

Whatever is/was wrong with the one I got was not a simple fix; some kind of defect deep in the windings (like a nicked phase or something) is likely the issue. As such, even if it had a simple disassembly process, it wouldn't have mattered. Personally, I generally only pull apart DD motors to add statorade, replace halls, add a temp sensor, or redo phase wires on motors which have spun out. Since the GAA comes with a temp sensor, has the best-in-class torque arm, and can be filled with statorade through a fill port, I can sorta forgive the lack of side plate because, generally speaking, I should never have to open it.

What you get from Grin vs going anywhere else is a company that truly stands behind their products and will make you whole if something is going wrong.

But... at the same time, you aren't wrong about the price -- you could buy a complete entire motor, wheel, tire, etc from Leaf for, like, 1/3 the price and just have several on hand to swap out. And, honestly, my Leaf motors have been awesome, they're just heavier and on "older" tech. Also, while technically not required, I personally won't run a motor without a temp sensor and statorade any more, so I factor in adding those to the leaf motors part of the cost/process. (Case in point both of these motors in wheels + shipping was about $780. Meanwhile, the GAA, with wheel build/etc I'm pretty sure ran about $1200.) I consider the price difference the cost of supporting better "local"er manufacturing and early-stage adoption upcharge.

 

[ebike4healthandfitness]

Another negative may be that little/no troubleshooting or repair is possible on the Grin motor without delacing the rim - though maybe this doesn't matter, as you wouldn't be able to get repair parts anyway, away from home and all.

Having to delace the motor is a pain in the ass but the weight and only needing to take one bolt off is great in my eyes. I love being able to easily chuck my ebike into a car. With 2 big torque arms, that's always a lot more drama.

I think it would be ideal if that ease of removability could be coupled to a swappable wheel cage. This way the core of the motor (which includes back iron) could easily be removed from the wheel build.

Then you could swap that motor core around to multiple bikes very easily thus making one motor purchase effectively able to work of many motor purchases in some regards. That feature would really mesh well with the all axle nature of the GRIN motor.

I also think if possible a non disc side plate option would be a great idea as it would allow the benefits of the 45mm stator where normally a 27mm stator could only be used. The benefit of the wider 45mm stator includes not only better motor efficiency ( Nice! Very Nice! (Upcoming Grin 45mm Direct Drive motor)) but also a lighter wheel build due to the wider distance between spoke flanges.

 

[Mongo]

@ebike4healthandfitness, do you mean something similar to (now defunct) Kindernay's IGH cage, only supersized?

 

[ebike4healthandfitness]

@ebike4healthandfitness, do you mean something similar to (now defunct) Kindernay's IGH cage, only supersized?

View attachment 360527

Yep.

 

[chuyskywalker]

There are motors out there like this; take for example the RoadRunnerPro motors have a disconnectable motor and a split rim assembly that even supports tubeless installs.

The downside to this (and even the simple side place of common hub motors) compared to the grin setup is...weight! There's some evidence around (youtube comments, I think) where Grin has responded that by going with this design vs the typical side plate, it saves something like 1-2 lbs in extra material, screws, etc. I imagine the RRP "fully disassemblable" type motor setup adds a TON of weight to keep it strong enough when it's so many separate parts.

 

[neptronix]

I think it would be ideal if that ease of removability could be coupled to a swappable wheel cage. This way the core of the motor (which includes back iron) could easily be removed from the wheel build.

More cost, maybe weight, and complexity though. The motor is already above most people's budgets.

I'd rather have light weight. If they are built correctly ( and i imagine this is the case now ), there'd be little to no no reason to open them in the first place.

Normally i'm all about reparability but in this case, the hub motor really does need to lose some weight.

 

[ebike4healthandfitness]

There are motors out there like this; take for example the RoadRunnerPro motors have a disconnectable motor

The GRIN 20" cargo wheel is also disconnectable via the cargo rim adaptor:

Grin All-Axle Hub CBW3 20

Custom Build of All-Axle Hub Motor into 20

ebikes.ca

New lightweight wheel for heavyweight cargocycles

LEVA-EU Member Alligt introduce their third 20″ wheel, CBW3 (Cargo Bike Wheel 3), made of high quality plastic with fiberglass. It is designed for the heavier multitrack cargocycles up to 600 kg with 4 wheels. After some further testing, Alligt is hoping to release it for a static load of 150 kg...

leva-eu.com

Alligt Cargo Bike Wheels

 

[Ethanator10000]

I got a bunk motor many months ago and have yet to send it in, just been too busy. It has a knock at high RPM and a halls issue.

What does the knock sound like?

My all axle V3 has a small sound that's kind of like a low knock at high RPM, but this is my first ebike and I thought it was normal. I put 3000km on it so far, link to video on google photos.

I've been feeling like my ebike has been feeling "draggy" but I'm not sure if it's just me having gotten used to it and it's not as exciting anymore, or if there's actually something going on. If there is something I'm not sure if it's the front all axle motor or my rear nexus IGH. Both are expected to have more drag than a normal hub but I'm not sure what's normal for the all-axle in particular.