New GNG mid-drive 2500W

[Overclocker]

As demanded and reviewed by our customers, various improvements are added into our new belt /chain reduction kit, and they are now in testing. The kits will be available in Sept/ Oct!
Feature:
- Handle up to 2500W power
- Triple chainwheel with extra bearing to offset the angular torque
- 148mm taiwan made ISIS bottom bracket
- 25mm htd 5m 12T/80T Belt system with bracket tensioning.
- 219H chain secondary reduction with redesigned tensioner wheel
- Bracket designed for 68mm/73mm bottom bracket
- Configurable controller
Stay tuned! testing video will be uploaded soon.

from GNG's facebook page. hmmm....

 

[r3volved]

Lol ya I saw that
They lightninRod'd their kit...good on them IMO.

 

[spinningmagnets]

They track sales and demographics of their customers and their competitions customers. I'm willing to bet they anonymously bought a small block Lightning Rods kit to evaluate and reverse engineer...

 

[LightningRods]

Pretty funny. One American working out of his garage kicked their ass and made them redesign their crap. Game on GNG. Try to keep up, bitches.

 

[spinningmagnets]

LOL!...

"...I'm willing to bet they anonymously bought a small block Lightning Rods kit to evaluate and reverse engineer..."

There is absolutely no doubt.

 

[slowhands]

Pretty funny. One American working out of his garage kicked their ass and made them redesign their crap. Game on GNG. Try to keep up, bitches.

I doubt they will have the quality of LR, and I'm sure they will be unable to update the design as rapidly. But they will cost less. I suspect they will screw some things up, but price will drive.

Life is unfair. This design was inspired by GNG, then greatly improved by crowdsourcing the design by this group. Mike did most, but the user feedback was heard. As an example consider the recent change adding back the tensioner on the secondary chain, by popular demand.

I suspect LR will still have all the business he can handle, especially on customs.

 

[LightningRods]

I've always expected this reaction from GNG. Given the Chinese proclivity for copying other people's designs, turning the tables on them was asking for a response. I decided from the outset that at the very least I would force GNG to produce a better product and not sell people outright garbage. The first GNGs were atrocious and were bad for belt drive, bad for mid drives, and bad for the e-bike industry. There were a lot of unhappy customers. GNG's response? "Please to enjoy." I think they will be less arrogant now.

I've diversified into mid bike drives for bikes like the Luna Cycle and cargo bikes. I'm also working on a new 'clean sheet' mid drive that will eliminate some of the fundamental design flaws of the GNG. There is still a lot of room for improvement. My only problem at this point is having enough time to do everything that needs to be done.

 

[1KW]

http://www.gngebike.com/belt-chain-motor

specs on the "2500w" motor however the product is not on there yet.

FEATURE:
- Temperature sensor in the internal core compatible with cycle analyst V3 ( 10K NTC thermistor with a beta constant of 3900.)
- Thick motor wires handling up to 50A continuous current.
- Compact aluminium body with maximum amount of copper mass
- Handling up to 72V at 40A
MOTOR SPEC.:
Weight 2.68 kg
Rm 73 milliohms (phase to phase)
Kv 67 rpm/V
Kt 0.143 Nm/A
Km 0.53 Nm/√W
Specific Km 0.20 (Nm/√W)/kg
Rotor OD 79mm
Stator OD 119mm
Stator ID 79.8mm
Stator thickness 25mm
Lamination thickness 0.5mm
Magnet thickness 4.2mm

 

[Samd]

I'm quite excited by it.
And to be somewhat fair, it wasn't just one american redesigning it, it was input from all of us over 140 pages trying our own stuff as well as Mike's iterations.
https://endless-sphere.com/forums/viewtopic.php?t=42785#p625050

 

[LightningRods]

I'm very grateful to the E-S community for all of the feedback and information provided as well as the financial support of the early customers who waited over a year for the first L-R drives to come out.

One serious mistake that I believe Jon has made is that he's overestimated the impact that my drives have had on his business. The Bafang BBS02 is what has been taking the bulk of his low end business, not me. Now he has the Bafang HD to contend with. Maybe he should have improved the Gen 2?

Now you guys have some decent cheap mid drives to choose from. Things have changed a lot in the e-bike business over the last three years.

 

[izeman]

there will always be an after market for high(er) quality custom products.
and i think it was never your intention nor possible to compete with mass production.

 

[LightningRods]

You're totally correct izeman. Fixing the GNG was just Mid Drive School for me. Like I said before, I've always expected GNG to bounce back and integrate my improvements. To be honest, I'm surprised that it took him so long. :lol:

 

[TorEddy]

As a previous owner of your LR kit, and a potential owner of the new Bafang BBSHD, I still feel none of them are perfect.
What I would like to see, is the GNG motor implemented like the Bafang BBS, but with the correct gearing and torque throttle.
More stealth, better protected from grit, and less 'slack' in the drivetrain, would be welcome features.
The Bafang way of mounting the motor, eliminates the pulling and twisting action of the secondary GNG chain, which is nice.
The way Bafang is integrating the controller into the motor is also nice, and makes for a clean look.
All in all, I like the new Bafang and GNG kits, but hopefully the clean sheet project you are working on will be better..
I saw a guy here on ES, mounting his GNG motor inside his frame. Nice idea for the new full suspension frames with curved downtube.

 

[gman1971]

I'm very grateful to the E-S community for all of the feedback and information provided as well as the financial support of the early customers who waited over a year for the first L-R drives to come out.

One serious mistake that I believe Jon has made is that he's overestimated the impact that my drives have had on his business. The Bafang BBS02 is what has been taking the bulk of his low end business, not me. Now he has the Bafang HD to contend with. Maybe he should have improved the Gen 2?

Now you guys have some decent cheap mid drives to choose from. Things have changed a lot in the e-bike business over the last three years.

Hey Mike, been reading your comments for quite a long time (I am the guy who emailed you about the damaged Gen2 GNG kit) Unfortunately for me, your stuff is way above my price range, but I am beginning to understand why perhaps I should've spent some more money and get something more reliable.

I have nothing to compare my GNG Gen2 to: my Gen2 kit was my first build. Let me begin saying that it was a fairly hard endeavor to get it to work. After understanding better what it is being talked about in this place, I can say that the kit was decent at best: the supplied plates seem to flex under load, and that caused it to throw drivechains until I got it sorted out; and what did puzzled me was the fact that the kit stock was like 1000 watts, rather than the advertised 500watts... Why underrate the kit? Kit is powerful tho, 32mph on the flats is a fairly decent speed for an MTB. Then the planetary gear issue, which I am pretty sure my planetary gears are going.. which sucks for a kit that is barely two weeks old...

I am sold on ebikes now and I if I don't get the Gen2 issues resolved fairly quickly I'll consider the idea of going rear hub motor instead... which means less things to break.

G.

 

[LightningRods]

G-

I'm sorry that I can't help you with the planetary issue on your Gen 2. I just never got involved with the Gen 2 to that extent. And now you're finding out what GNG 'customer service' is like.

If my mid drives are out of your price range you should buy a Bafang from Luna Cycle http://lunacycle.com/motors/bafang-...750w-mid-drive-with-upgraded-3077-controller/ Eric is blowing the BBS02 out at prices that are pissing off everyone else that sells them. Eric will answer your emails and will provide support. He also sells hub motors but I personally wouldn't go that way.

Mike

 

[gman1971]

No worries Mike,

I am really tempted about that; and the fact that I eyed the BBS02s before but the fact that I would be stuck in single chain ring was what steered me towards the Gen2 GNG (which I've extended to accept two chainrings with no modifications to their hub) If my battery was to go using the BBS02 whiling climbing a 9% hill like the ones around here I feel I'll be SOL... My GNG is running a 32T and 42T chainrings in addition to the supplied drive chainring.

Not sure where those planetary gears can be sourced... maybe I haven't dug hard enough around ES... but I've seen that Lyen sells some planetary gears, unfortunately I won't be able to tell what kind of gears/sizes I need until I get home and take it apart.

In the terms of GNG customer service, well, this just started 3 hours ago and Jon has been responsive so far, or at least he has bothered to answer my emails rather quickly with some solutions; but we'll have to see how this fares out. A motor that goes bad after barely 2 weeks of use is something to consider if you are going to buy from GNG. I do live in a very hilly area so that perhaps could be the reason why it failed... (average 8% grade hills around here in Wisconsin)

G.

 

[LightningRods]

Maybe you'll get lucky and get a new motor out of Jon, or at least some new gears. I'm sure he has a bunch of them lying around. The Gen 2 never caught on for some reason.

 

[gman1971]

Maybe you'll get lucky and get a new motor out of Jon, or at least some new gears. I'm sure he has a bunch of them lying around. The Gen 2 never caught on for some reason.

Not sure what the problem is yet, but it would be nice if Jon did something about it without me having to take apart my new motor. The surprising thing is that the motor only took 200 miles to die... and why on Earth would they use plastic gears on these motors??

As for Gen2 not selling, well, considering how much you redesigned their Gen1 kit it is kinda easy to assume people saw it wasn't that great. The Bafang also is a 1 piece solution, no mess, no fuss... take BB out, put new BB in, install chain... bam... you're done. While on mine I had my fair share of issues every step of the way: it wasn't easy... and for a short while I almost took the sledgehammer to it because the chain derailing when I gave it gas it was ridiculous.

G.

 

[LightningRods]

... and why on Earth would they use plastic gears on these motors??

Planetary gears are a brilliant idea. If you look at the drawings for how they work you can't help but be amazed that someone came up with that idea. Unfortunately, you have your choice of metal gears which are noisy, or plastic nylon gears that are fragile and break or wear out. The Bafangs also have nylon planetary gears. If you push a Bafang too hard the gears won't last long at all. But if you run them at their power rating they seem to do pretty well. Better than the GNG Gen 2 apparently.

 

[gman1971]

... and why on Earth would they use plastic gears on these motors??

Planetary gears are a brilliant idea. If you look at the drawings for how they work you can't help but be amazed that someone came up with that idea. Unfortunately, you have your choice of metal gears which are noisy, or plastic nylon gears that are fragile and break or wear out. The Bafangs also have nylon planetary gears. If you push a Bafang too hard the gears won't last long at all. But if you run them at their power rating they seem to do pretty well. Better than the GNG Gen 2 apparently.

Agreed, the idea is indeed brilliant; perhaps the plastic material for these gears was a bad decision?

G.

 

[1KW]

does anybody have this new kit yet? I thought someone on facebook group got it early or something?

 

[slowhands]

... and why on Earth would they use plastic gears on these motors??

Agreed, the idea is indeed brilliant; perhaps the plastic material for these gears was a bad decision?

G.

Plastic gears are much quieter and cheaper than metal gears. Metal gears require complex, precise machining and heat treating, which is expensive. Their sound is a high pitched unpleasant sound at the high RPMs we use. So there are noise pollution and cost reasons to go to plastic gears. The same argument holds for belt driven gears. Cheaper quieter composite materials have advantages and disadvantages there too. This is a complex multi dimensional trade off, involving cost, durability, gear noise and other factors; no one answer pleases everyone.

The small Cyclone mid drive is amazingly powerful and durable, but the noise it makes is unpleasant. It has metal gears in the planetary. In contrast, Bafang and Bosch use plastic gears in the planetary and are much quieter. They work well if you limit the power but will wear quickly if you exceed their design limits. Here is a spectrum of mid drives from Cyclone and Bafang, to give you an idea of the sound and performance options.


500W single motor Cyclone: https://www.youtube.com/watch?v=wV0gCh_tkIs
2400W double motor Cyclone: https://www.youtube.com/watch?v=Y6o-g7YeC4Q
Bafang 750W BBS 02: https://www.youtube.com/watch?v=rs3MwYfEvro
Bafang 1000W HD: https://www.youtube.com/watch?v=2R73OPttFwk

 

[gman1971]

Nice, the 1000W bafang will probably the one that I put on my wife's 29er bike...

I understand there is a trade off but I really don't mind steel; or basically anything that makes the kit more resilient... which is what I've done for the past few days... strengthen every weak component on this kit... So metal gears whine doesn't seem to bother me much from those videos... maybe after you've heard an Formula One V10 up close going through the gears and the sound of the gears going on my bike reminds me of those from afar... so I must be the only one who likes the old F1 sounds that these mid-drives make. lso the sound from the motor is what I go by when I need downshifting as well...

GNG kits seem to be good tinkerer kits but IME don't expect it to work out of the box without some upgrades and troubleshooting (not the only one in here that has been through that); while it provides the starter kit to get you going, it will be up to you to find the parts to bulletproof it... I had a local machine shop drill the broken stock motor shaft (cheap steel) so I could use a hardened steel shaft inside... the stock square keyway for the pinion also sheared off, so I had to drill two dutchman pins (round keyways) that should hold in place even if the shaft twists around like a pretzel... the chain in the kit was worthless too: a mega-cheapo BMX chain with lose pins... bought a KMC hardened BMX chain and the difference is night and day. I will be making an additional bracket to hold the motor from moving up and down, the hose clamp is kinda an el-cheapo solution for something that should've been addressed with a real bracket... The chain tensioner was another joke... took some extra parts and creativity to get it right.

But for 320 it sort of worked...

G.

 

[emaayan]

i saw the early version that kit and when i saw the paper thin upper sheets he was about to use , i sent jon a picture of how my l-r kit looks now as a warning of what would happen if he were to choose that path. that prompted him to re-design the sheets, but instead of going with thicker aluminium ones, he went for stainless steel ones.

but it's interesting that his upper sheets are designed with other stuff as well. but i can't see them clearly.

but for one thing up until now, i've never seen an off the shelf mid-drive that has a crank with double bearing that deals with the angular stress, although the chainring don't seem much, (i wonder that bcd they are) .
and don't see a way to have a torque sensor (jon told me they are looking into it, don't how much of it cam through) .

but that's what good about the gng , it's simple design allows you to have improvements and modifications even in my gng 2015, and considering to do now, , bafang looks neat, and closed, but if it's plastic gears fail you can't exactly replace them with something stronger.

 

[gman1971]

i saw the early version that kit and when i saw the paper thin upper sheets he was about to use , i sent jon a picture of how my l-r kit looks now as a warning of what would happen if he were to choose that path. that prompted him to re-design the sheets, but instead of going with thicker aluminium ones, he went for stainless steel ones.

but it's interesting that his upper sheets are designed with other stuff as well. but i can't see them clearly.

but for one thing up until now, i've never seen an off the shelf mid-drive that has a crank with double bearing that deals with the angular stress, although the chainring don't seem much, (i wonder that bcd they are) .
and don't see a way to have a torque sensor (jon told me they are looking into it, don't how much of it cam through) .

but that's what good about the gng , it's simple design allows you to have improvements and modifications even in my gng 2015, and considering to do now, , bafang looks neat, and closed, but if it's plastic gears fail you can't exactly replace them with something stronger.

GNG failed yet again, the freewheel broke today when I was leaving work, first pedal stroke... all of the sudden I am pedaling in thin air... no now is an e-motorcycle, rather than an e-bicycle... not good. Fixing this little "whoops" from CRAPO-GNG is going to cost me 180 dollars to get the three chainring with ISIS BB from Cyclone, and PRAY it works.

I understand Bafang is all closed, proprietary and whatnot, but if you keep it under what it was designed to go for things are less likely to break than the GNG. Do a youtube and find how many Bafangs run and how many GNG's run... not so many; really.

IMO, if you don't want to deal with sub-standard parts that wear out and fail after just 300km then my unsolicited advice would be to AVOID GNG, at all costs. Go front hub if necessary, but anything will be less frustrating than anything GNG makes... see Lightning Rod's kit... the only thing he kept was the motor!! That alone should give you an idea how BAD it really is.

I don't know how good or bad the Bafang kits are; but it sure looks like its a heckuva lot more durable than the GNG junk.

This 2500 Watt kit will probably self-destruct the first time you punch the throttle; either the motor shaft will snap, bend, twist, dislodge; the sprocket keyway will snap; the chain will snap; the freewheel will disintegrate after a few miles, the mount might flex and snap... name your failure; because if it can fail, it will, and at the worst possible moment just because its a GNG...
The local machine shop told me flat out the motor shafts was regular steel (they did the spark test), the mounting brackets that are paper thin flex with gusts of wind... chain that is of dubious quality at best breaks; and a motor controller that given the reliability of the other components who knows if one day my bike will go up in blazing LiPo flames of glory with me clipped to it... just like WW II fighter planes, when the engine caught fire you had to figure out a way to bail out, otherwise you'd become BBQ for the fishes...

Seriously, I am not a shill for Lightning Rod, but his kit seems like a better alternative than any GNG stuff. What is it they say? Imitation is the sincerest form of flattery?

Moral of the story: If you have the money, don't cheap out, get something better with aftersale service; and so far GNG seems to be synonymous of cheap and you're SOL.

G.