Bafang G310 geared hub - 11:1 reduction ratio!!!

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HrKlev   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by HrKlev » Apr 19 2021 12:31am

ilu wrote:
Apr 18 2021 2:45am

Could it use the same gears as G310/311? Those seem to be the same 18-33 gears for both motors and available at least on Aliexpress.
Thanks! Found the shop on aliexpress. They had measurements for the gears, and turns out tve G310 and G311 uses very different gears. I will have to open up and measure the g370, hopefully I can use one of them :) If not, I'll have to get a roll of nylon filament and see if I can draw it up and print something. Not expecting them to be strong enough, but a fun experiment :)
Hubdrive as middrive, with torque sensing EMTB build: viewtopic.php?f=6&t=107622

6x6 conversion: viewtopic.php?f=34&t=109567

TDB   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by TDB » Apr 19 2021 12:39am

HrKlev wrote:
Apr 19 2021 12:31am
ilu wrote:
Apr 18 2021 2:45am

Could it use the same gears as G310/311? Those seem to be the same 18-33 gears for both motors and available at least on Aliexpress.
Thanks! Found the shop on aliexpress. They had measurements for the gears, and turns out tve G310 and G311 uses very different gears. I will have to open up and measure the g370, hopefully I can use one of them :) If not, I'll have to get a roll of nylon filament and see if I can draw it up and print something. Not expecting them to be strong enough, but a fun experiment :)
Do you have links?

HrKlev   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by HrKlev » Apr 19 2021 1:37am

Sure :) Does this work, or does it just lead to my login or something else? The shop is called
"46 Ebike Store". They also has the motors, so nice to have stored (g310, g311, g370)

https://a.aliexpress.com/_mK6e4jp

https://a.aliexpress.com/_mKETMxD

Update: G370 gears are different to both g310 and g311 unfortunately. I have contacted the seller, but Im starting to think the printer is my only hope if I want to get this motor going again.
Hubdrive as middrive, with torque sensing EMTB build: viewtopic.php?f=6&t=107622

6x6 conversion: viewtopic.php?f=34&t=109567

ilu   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by ilu » Apr 20 2021 2:19am

HrKlev wrote:
Apr 19 2021 1:37am
Sure :) Does this work, or does it just lead to my login or something else? The shop is called
"46 Ebike Store". They also has the motors, so nice to have stored (g310, g311, g370)

https://a.aliexpress.com/_mK6e4jp

https://a.aliexpress.com/_mKETMxD
I bought by G310 motor from this seller. It was super cheap during a sale, but they did not have the motor in stock even though the page said it was. So it took more than a month before they shipped, when they finally did it arrived really fast with a courier. The motor also was 13T wind rather than 'standard' 10T wind which they told me it would be when I asked. Luckily this was not a problem after all as I use it in 29 inch wheel.

So not the most reliable seller, but at least they do communicate when messaged and I would buy spare parts from them if I needed.

hias9   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by hias9 » Apr 20 2021 6:13am

12T and 13T seem to be "standard" for the G310. I think the faster windings are only available at Grin.

Take care with the phase amps on your 13T. 30A phase results in the same torque as 39A phase on a 10T. My planetary gears only survived about 200 miles running 30A phase on a 13T.

TDB   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by TDB » Apr 20 2021 8:19am

HrKlev wrote:
Apr 19 2021 1:37am
Sure :) Does this work, or does it just lead to my login or something else? The shop is called
"46 Ebike Store". They also has the motors, so nice to have stored (g310, g311, g370)

https://a.aliexpress.com/_mK6e4jp

https://a.aliexpress.com/_mKETMxD

Update: G370 gears are different to both g310 and g311 unfortunately. I have contacted the seller, but Im starting to think the printer is my only hope if I want to get this motor going again.
That works. Thanks.

I'll pick up a another motor and controller this week. Options are good.

adcockj   10 mW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by adcockj » Apr 22 2021 2:28pm

I had asked back on 11 April about the type and amount of oil to add to the G310, so I thought I'd report on what I did...

I bought a 4-oz bottle of SuperLube 100cSt Silicone oil. (The Opticool sounded good, but I didn't want to spend $100 plus tax and shipping to end up with 50ml of oil.)

It was not difficult to get access to add the oil. I didn't drill any holes, but by removing the 6 security torx screws and the 6 Phillips screws around the cassette, I could just lift that cover off (with just a little knife insertion on the edges outside the torx screw locations to get it started). I added 40 ml...probably should have done 50ml, but I just wanted to be cautious.

Everything seems fine. I've done a couple of 25-mile rides (almost 800 miles on the motor now), without any issues.

One caveat: I could not figure out how to get the nut off that holds the cassette onto the drive side axle. (I watched the Grin video, and they said it was easy to remove the jam nut, but didn't show removing the main nut underneath...it was just gone when they pulled the motor apart.) The jam nut was easy, but the 17mm nut itself, which is not a regular hex nut -- just two flat sides -- and sits down inside and is "protected" by a small metal collar, was another story.

The way I removed the cover for access, it wasn't necessary to get this nut off. But if/when I need to be able to remove the sun gears, I'm going to be in trouble since I couldn't get to the screws underneath.

Is there some special wrench that would grab the two flat sides of that nut? Or do I need to just grind that little collar back?

Yamarlo   10 µW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by Yamarlo » Apr 22 2021 3:08pm

I went for 10 Cst pure Silicone Oil. Lower viscosity meens less drag, but i had small problems with leaking. Nothing wild but next time i would go for minimum 20 Cst. I also added PTFE for less friction in the gears.

Silicone oil seems common for plastic (nylon) gears. I found a source with more information about compatibility of different kind of oil for different materials and a guide which oil und additive to use.

https://ecllube.com/resources-for-engineers/
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Regarding the nut, i used a plier to hold /lock the nut and turned the axle from the other side of the motor with a wrench.

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neptronix   100 GW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by neptronix » Apr 22 2021 3:28pm

You should really try opticool. Their site lists the kinds of materials opticool-H is compatible with. I quizzed them and it seems to have the highest material compatibility of any coolant i've seen.

Do let us know how silicone oil goes. One big thing you need to know is if the fluid is compatible with nylon though, as your gears are likely made of it. I would guess that opticool H is rated to be compatible with nylon.
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1N4001   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by 1N4001 » Apr 23 2021 3:04am

adcockj wrote:
Apr 22 2021 2:28pm
One caveat: I could not figure out how to get the nut off that holds the cassette onto the drive side axle. (I watched the Grin video, and they said it was easy to remove the jam nut, but didn't show removing the main nut underneath...it was just gone when they pulled the motor apart.) The jam nut was easy, but the 17mm nut itself, which is not a regular hex nut -- just two flat sides -- and sits down inside and is "protected" by a small metal collar, was another story.

The way I removed the cover for access, it wasn't necessary to get this nut off. But if/when I need to be able to remove the sun gears, I'm going to be in trouble since I couldn't get to the screws underneath.

Is there some special wrench that would grab the two flat sides of that nut? Or do I need to just grind that little collar back?
Yeah, I had the same problem. That nut is often on so tight that it can't be loosened, and I could not find a tool that would fit in there to get a proper grip. I wonder if Grin has an unusual tool that gets in deeper.

Major Clod   1 µW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by Major Clod » Apr 26 2021 1:13pm

I'm looking at building an e-bike for my son using a spare 20" MTB frame. The G310 looks great to me given its light weight. I'm trying to choose between the standard and fast windings from Grin, so looking for some insights on which way to go based on the following.

- primary goal is to extend gravel riding range and also use to assist his climbs on singletrack
- expected bike + rider weight 40-45kg
- used in 20" wheel now, 24" wheel in 12-18 months time
- torque pas only, no throttle (he still needs to put some effort in!)
- max target assist speed is 25kph
- likely 36v battery but open to suggestions (probably get a custom pack built locally to fit his frame)
- using the CA3 to keep it all easy

He's a fantastic rider already, and the goal is to just help him keep up with mum and dad for longer rides, not setting any land speed records etc.

Any thoughts are most appreciated.

HrKlev   100 W

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by HrKlev » Apr 26 2021 3:23pm

Standard wind on 36v will do about 29kmh in a 20" and about 33kmh in a 24" according to the Grin motor simulator, so no need for the fast wind. A baserunner, cycle analyst and a bottom bracket torque sensor would give you what you want (you can use whatever controller you want with the cycle analyst, but the baserunner is plug and play without soldering, and it is very compact). You need to configure and finetune the baserunner and cycle analyst to get the behaviour like you want, but its not a huge deal if you are familiar with diy stuff.

Another option would be a KT controller that is flashed with open source software. That would do torque sensing, but I think it is a bit more fiddling to get it to work.
Hubdrive as middrive, with torque sensing EMTB build: viewtopic.php?f=6&t=107622

6x6 conversion: viewtopic.php?f=34&t=109567

Major Clod   1 µW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by Major Clod » Apr 27 2021 9:30am

HrKlev wrote:
Apr 26 2021 3:23pm
Standard wind on 36v will do about 29kmh in a 20" and about 33kmh in a 24" according to the Grin motor simulator, so no need for the fast wind.
Awesome thank you, that confirmed my own thoughts!

Yamarlo   10 µW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by Yamarlo » May 08 2021 4:41am

Yamarlo wrote:
Apr 22 2021 3:08pm
I went for 20 Cst pure Silicone Oil. Lower viscosity meens less drag, but i had small problems with leaking. Nothing wild but next time i would go for > 20 Cst. I also added PTFE for less friction in the gears.

Silicone oil seems common for plastic (nylon) gears. I found a source with more information about compatibility of different kind of oil for different materials and a guide which oil und additive to use.

https://ecllube.com/resources-for-engineers/

Screenshot_20210422_215145.jpg

Screenshot_20210422_215449.jpg
Screenshot_20210422_215209.jpg


Regarding the nut, i used a plier to hold /lock the nut and turned the axle from the other side of the motor with a wrench.
Edit: went for 20cSt not 10

alfy22   1 µW

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Re: Bafang G310 geared hub - 11:1 reduction ratio!!!

Post by alfy22 » May 19 2021 3:47pm

Hi,
Im having issues with my e-bike build and G310 motor. I have a Grinfinion 20A controller and my build is set up with pedal assist. I use my ebike as a daily commuter and everything had been working great going on 3 years, but now when I pedal, the motor just shudders and then I lose all power. I have ruled out battery and PAS issues. Checked controller mosfets for shorts and that all seems ok although the resistance on one phase wire was less than the others, around 2kohm. I assumed this was ok or could this be an issue?
I disassembled the motor and noticed what looked like a bit of corrosion on the stator and coils - nothing major, see pictures - a bit of white oxidation on the outside and rust on the inside of the coil casing. otherwise everything looked ok including hall sensors.

Could water have damaged the motor? Could this be the issue and is it fixable/replaceable or do I need to replace the entire motor? I live in Norway and use the bike year round in pretty harsh conditions- rain, snow, salted roads etc so it would not surprise me but expected it to last longer…

Thanks for any help
Kris
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