GNG Drive Gen2

[Electric Junk]

My hub motor was not holding AT fluid anymore i found a leak in the bottom.....The red gasket sealant was hard and cracking...i found permatex anaerobic sealant should do a better job at forming a gasket.

Also i decided to upgrade the phase wires to 16 from stock.

I have been getting 35 to 40 miles out of 11ah, 15 to 20 watt hours. I have been pedalling a lot to keep the temp down.

Peak wattage on acceleration has been around 850....

I hope with the mods i can break 900 watts.

 

[Masure]

Hi guys,

I'm coming trying to find an alternative to my Bafang BBS02 which can't be fit on my carbon frame. The frame BB shell is 18mm thick and it's too much for the BBS02 clearance between the motor axle and the motor shell. BBS02 has 14mm clearance here which fits metal bottom brackets easily.

So my first question (before the next ones ) is :

How much clearance will I have with the GNG Gen2 here ? Watching the pictures tells me there is much room but I didn't check before buying my BBS02 and I got screwed so I take care of this now .

I hope this one will fit because there are not so many cheap and easy mid drives. I'd like to keep my carbon frame even if I know carbon is kinda stupid with 8kg electric kit.

Regards

 

[Masure]

What's the distance from the drive chainring plane to the bottom bracket center plane ? Same question from the reduction chainring.

I'd like to know the chainring sizes that will fit my frame.

 

[John Bozi]

can or has anyone run this motor on the left side as a direct chain drive to brake rotor sprocket? what would need to change? reversing the motor... is the motor sprocket threaded in anyway...

is there a freewheel on the sprocket? would it be an issue to run without a freewheel apart from a constantly spinning chain and motor even when not in use?

I love my bafang bbs02 for the gear side but would be nice to add some more power to the other side.

 

[lantice13]

It's a modified geared hub motor similar to crossbreak's project. it freewheels internally so I'm not sure if the clutch would engage the shaft if you spin it the other way? I don't think the sprocket is threaded on the shaft.

 

[1KW]

anybody else get one of these? look like a cheap small fun package that can aid in commuting, or make you pedal your dh bike like a roadbike on the streets.

 

[Joe T.]

I am looking at the 2015 UPGRADED Gen2 GNG. I want to build a Fat bike aimed at riding the trails. I want it as simple as can be. The Gen2 looks as simple as it could be. My only Ebike experience is with the GNG 48V belt reduction. I like the power and after some Lightning rod updates it is real nice for the trails and pedaling along. My new bike project is not for me as I love my bike. I just want to make a less complicated Ebike that can keep up with me.

I have no problem going with another belt reduction but less parts would be nice. Anyone know if the 48V Gen2 will keep up with the belt reduction version? This too will be a store bought 48V lithium battery.

 

[lantice13]

It's still complicated..... stock configuration is not reliable. mainly the new freewheel crank they supplied the 2015 version is garbage. the old version of that chainring is better. Most fat bike got 100mm+ wide bb shell, I dont see this fitting at stock configuration, need to widen/ extend the bb mounting sheets. I have their new 2015 gen 1 and their older gen 2.

 

[lantice13]

also in comparison to the gen 1, the gen 2 will run hotter at 48v at the same power level as the gen 1. I would just keep it at below 1kw as it already runs hot at 750w and this is on a dual motor ebike where the Gen 2 motor is not stressed too bad. Cyclone tw have a new kit that uses a similar motor than the gng gen 1 but instead of using a jack shaft, it's using a planetery gear box. same price as the GNG gen 1. here is the thread for that kit. http://endless-sphere.com/forums/viewtopic.php?f=28&t=69867&p=1054299&hilit=cyclone+3000w+mid+drive#p1054299

 

[neptronix]

I had a feeling that they are still producing unreliable mechanical bits. What a shame. I'd love to have one but don't want to deal with any of these issues.

 

[Joe T.]

It's still complicated..... stock configuration is not reliable. mainly the new freewheel crank they supplied the 2015 version is garbage. the old version of that chainring is better. Most fat bike got 100mm+ wide bb shell, I dont see this fitting at stock configuration, need to widen/ extend the bb mounting sheets. I have their new 2015 gen 1 and their older gen 2.

I'm not worried about getting it to fit. I want to know if the power will be the same as the GNG kit on my bike. I run mine bone stock from GNG. No power mods or tricks. Just the stock controller as is. I'm good with that. I think they claimed 450W when I bought it in 2013. I just want to know if anyone knows from experience the 2015 Gen2 will hold up. I'll deal with the freewheel if it fails. I like the clean look. I don't want to mess with the planetary gears.

 

[lantice13]

the gen 2 will be weaker than the gen 1. I have both kits on 2 different bikes. I don't think the gen 2 can keep up with the gen 1 since you'll need to run less amps with that small geared motor to prevent overheating.

 

[lantice13]

I had a feeling that they are still producing unreliable mechanical bits. What a shame. I'd love to have one but don't want to deal with any of these issues.

Nep, I agree! I can't see these kits replacing my good ol 10T MAC geared hub as a reliable daily commuter, even my new build using the 2015 gen 1 kit...... that thing is hard to ride as you need to switch gears all the time to get into the right ratios else it will suck amps like crazy and there is always things to adjust..........

 

[lantice13]

I don't want to mess with the planetary gears.

well the gen 2 uses planetery gears as they are converted geared hub motors?

 

[Joe T.]

yes, they're all planetary reductions

I know that part. I'm looking to find out if there are premature failures to be expected. A belt failure is easy to fix.

 

[lantice13]

Mine still works after 3 years....but my setup is dual motor. GNG gen 2 mid and a rear Magic Pie 2 hub motor. if you really need a simple mid drive setup, just get a bafang BBS02 and mod it to use an external controller. Issues reported by some users are internal controller failure due to improper thermal management. If something breaks on the bbs02, you can always get parts from our known vendors here.

 

[lantice13]

I'm looking to find out if there are premature failures to be expected. A belt failure is easy to fix.

Like geared hub motors, the clutch and gears are mostly the one that goes if you have a failure in one of these. then after those the usual things that stops working if you overheat a motor. then if you still decide to use their new 2015 freewheeling crankset..... that would only last for a week of moderate riding, then it falls apart..... literally, the bearing just pops out and spews the ratcheting mechanism out. The mounting hardware has been reliable, even the older versions that bends a lot. other than the fact that it runs hot at only 48v, 1kw peak..... it's an ok kit at lower voltage and power.

 

[gman1971]

I purchased a (my first ebike) Gen2 GNG 2015 mid-drive two weeks ago and until today it did work, but it took a lot of effort to get it to work; and I say today because unfortunately I suspect my planetary gears are shot, and I suspect that because motor started making a weird noise and its fairly hard to turn backwards.

I find the motor to be the weakest link in the setup, the rest seems to be decently built ...

The crank freewheel isn't supposed to come apart while riding the bike since the crank arm actually holds it in place, so not sure how the thing can come apart while riding?? I didn't mind the freewheel separating while off the bike so I could lube it to make it somewhat quieter.

During initial installation I had more issues with the drive-chain coming off than anything else, mostly due to the mounting plates twisting under load. I do run the GNG controller and 12S lipo (48v) but I live in a pretty hilly area (around 8.5% grade hills) so I really needed a mid drive and this one was the cheapest first step into the ebike world. Right now I need to find a source for replacement steel gears for the planetary assembly.. and while Jon at GNG has been helpful so far, I am not certain if he will really be willing to help me with this matter... a motor that only lasts one week is kinda questionable.

G.

 

[gman1971]

yes, they're all planetary reductions

I know that part. I'm looking to find out if there are premature failures to be expected. A belt failure is easy to fix.

Well, as for premature failure I would say my motor is having issues after barely two weeks. I suspect planetary gear assembly. I do like the power tho, I get 32mph on the flats with 12S Lipo and aero position.

G.

 

[gman1971]

Youtube video of the motor failure on my GNG Gen2 middrive e-bike.

https://www.youtube.com/watch?v=D3KfNuHe1q8

 

[gman1971]

Well, I couldn't wait so I took the GNG Gen2 motor apart down to spare parts and I found out why it failed.

The good news is the planetary gear assembly is fine, but the bad news are that the jack shaft is broken at the back, where the bearing of the outrunner can mates with the stator. The noise I was hearing was the actual magnets rubbing against the motor armature so that explains it. Pretty shitty for a motor to fail like this in like a week of use... and in this particular point!!

I also noticed the inner shaft was bent too, so it was a matter of time before the axle snapped, now, how it got bent is beyond me... but now I know that to fix this all I need is to find a new jack shaft which I am sure they are much easier to come by than a set of who-knows-what gears... which I'll measure as well and probably replace with hardened steel. I might try to build a jack shaft out of a solid 10mm shaft rather than this wissywuss step down to 6mm shaft.

After taking it apart this motor looks to me like a supersized RC outrunner motor with a planetary gear, so no wonder why it has so much torque...

G.

 

[lantice13]

It's probably the larger drive sprocket and controller at fault.... I got the older version that got a smaller sprocket and that thing still working but it's on a dual motor bike so it doesn't get strained that much. Also the stock 9fet controller is not programmable so as it is,it just hammers the motor from dead stop with some crazy batt/phase ratio. If your able to source parts for it and get it repaired, I suggest getting a programmable controller like the Lyen,em3ev and find the battery and phase amps combination that gives it a smooth start. The new 2015 gen 1 kits are also problematic..... I killed that new version freewheeling chainrings and crank in a week... not even 100miles in them so to the old style freewheeling chainring/crank I went and John charged me $67 for a replacement which should had been free if the kit got some sort of warranty in them. it's a GNG kit... so yeah that's not surprising, buy at your own peril.... if you don't need 2kw on a mid drive, the new bafang BBS-HD is much better than both these GNG mid drives at 1kw-1.5kw. I had the the privilege trying one and compare it to my own 2015 GNG gen 1 kit. Really regretting it now..... lol waiting for my gen 1 to self destruct so I can get rid of this carp. :x

 

[gman1971]

It's probably the larger drive sprocket and controller at fault.... I got the older version that got a smaller sprocket and that thing still working but it's on a dual motor bike so it doesn't get strained that much. Also the stock 9fet controller is not programmable so as it is,it just hammers the motor from dead stop with some crazy batt/phase ratio. If your able to source parts for it and get it repaired, I suggest getting a programmable controller like the Lyen,em3ev and find the battery and phase amps combination that gives it a smooth start. The new 2015 gen 1 kits are also problematic..... I killed that new version freewheeling chainrings and crank in a week... not even 100miles in them so to the old style freewheeling chainring/crank I went and John charged me $67 for a replacement which should had been free if the kit got some sort of warranty in them. it's a GNG kit... so yeah that's not surprising, buy at your own peril.... if you don't need 2kw on a mid drive, the new bafang BBS-HD is much better than both these GNG mid drives at 1kw-1.5kw. I had the the privilege trying one and compare it to my own 2015 GNG gen 1 kit. Really regretting it now..... lol waiting for my gen 1 to self destruct so I can get rid of this carp. :x

Hey man, sorry to hear about your mishaps as well... Jon is locating a new jack-shaft, and wants 37 shipped express to my door... I am still trying to see if the guy will ship it free... I think its brand new... should've never failed; not with stock power ~22 amps at 50 volts...

I think I could fix the issue locally if I had access to a lathe (I live near Madison Wisconsin, BTW) What I think it will work is drill a 7mm inner hole through the broken shaft and insert a 7mm shaft; because right now that step down from 12mm to 6mm is huge and that causes all sorts of stress points in there. This is an outrunner motor and those have gobs of torque and a 6mm shaft isn't up to the task. I have 6mm shaft on my scorpion motors for my RC helicopters with a significantly smaller rotor... but a 7mm inner shaft should give it more strength and that combined with steel planetary gears this motor should be good for several horsepower, not that I am planning on going insane but good to have margins. I will also add motor oil inside the casing once I am done with this.

Any thoughts as to where I could find a lathe?

G.

 

[gman1971]

So, I did some thinking and the 2015 GNG Gen2 motor is bound to fail at that point exact point. The motor appears to be a hub motor, with a shaft that went side to side of the case, but since they cut one side now the motor suffers a very strong single side load component when the sprocket is pulling the chain so this creates a lever from the drive sprocket, the fulcrum at the main 12mm input bearing at the motor case and the other end where the weak 6mm end is getting the opposite side deflection. So the only way I can see this fixed is by making a longer 12mm shaft across the entire motor case; otherwise it will always fail at that spot, and especially so if the shaft wasn't drilled correctly.

G.

 

[gman1971]

Well,
One lunch hour and 40 bucks later my motor problems have been solved: A local machine shop drilled and taped a 6mm hole inside the shaft in 20 minutes and I then purchased the hardest grade steel automotive 6mm socket bolt I could get and it should do the trick. I'll post update tonight with the fixed bike.

The machinist that did the work also told me the shaft is a fairly low quality steel, so no wonder why it snapped; and I've inquired about cutting me a hardened steel motor shaft but with an upgraded 8mm back end and they said it wouldn't be much more expensive than what I already paid for drilling the hole inside the shaft. Therefore looks like I'll be doing that at some point if this fails.

So this gets my bike running again, for the short term at least and I'll start thinking about motor shaft improvements and metal gears so I can run 320 kW out of this motor if I ever wish to...

G.