GNG, 1000W 48V BB-drive, $400
- Thread starter spinningmagnets
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flyinmonkie
10 kW
There has been a lot of discussion already on what the different IGH's can handle power wise. deccano and a couple of others have munched the sram and a few other IGH's with RC set ups. Most that are using an IGH now are using the nuvinci hubs.
I think if a slipper clutch (like what Matt uses on his RC drives) was used, then any IGH could be used. It would eliminate the shock load from the motor. Also, not shifting under full power, but that helps keep dérailleurs alive as well.
Clay
I think if a slipper clutch (like what Matt uses on his RC drives) was used, then any IGH could be used. It would eliminate the shock load from the motor. Also, not shifting under full power, but that helps keep dérailleurs alive as well.
Clay
spinningmagnets
100 TW
You can also electrically snub the throttle signal, and also change the phase/battery amp ratio to make it more of a soft-start (no wheelies). I haven't done any of that, my spare time and money is tied up with a couple projects already...
Samd
10 MW
It'd be very easy to program a $20 arduino or similar to ramp the throttle signal from your real throttle, you could even have a potentiometer or two to shape the ramp up speed and duration...
Chalo
100 TW
flyinmonkie said:
Most internal gear hubs have a minimum primary gear ratio specification. The SRAM Dual Drive obviously violates all the published minimum primary ratio limits, but internally it's just a normal three-speed hub.
I know pedicab drivers who have lunched the gears in Sachs 3x7 and SRAM Dual Drive hubs without help from motor power. I wouldn't do it if I were you. But then, I wouldn't do several of the things that GNG drives do, which have uncoincidentally proven to be problematic. That hasn't slowed y'all down, though. Why not add some more stuff that will break and fail, to make your breaky faily kits even more entertaining?
Thud
1 MW
Hehe, Chalo cracks me up.... I am never offended when he voices his astonishment at other folks time utilization. His style is abrupt to say the least....we'll see if I feel the same way when he chastises the puke out of my recumbent comuter 
I am all for polishing turds, & this thread is right in my wheelhouse. I digress.
If you all read back a few years you will find that no internal gear hub has held up under ellectric power...even moderate power....we broached freewheels for guys to employ the dual drive 3 speed hub.
I can't remember if anyone had one last for a few hours.
Members 1000w, ausiejester & even Safe has had failures on road with other internal geared hubs. Add the jarring of off road & the failure is iminant.
The nuvici's seem to work....but I suspect you will see them needing a fluid change yearly on a minimum. I know of a couple of them slipping badly when used by the motored bike guys (more properly the "engine cycle" guys)
Green machine is running a new set up through a Rolloff speed hub...(which I suspect may be a mortal sin
) I am hopeful it proves to be a winner.
I am all for polishing turds, & this thread is right in my wheelhouse. I digress.
If you all read back a few years you will find that no internal gear hub has held up under ellectric power...even moderate power....we broached freewheels for guys to employ the dual drive 3 speed hub.
I can't remember if anyone had one last for a few hours.
Members 1000w, ausiejester & even Safe has had failures on road with other internal geared hubs. Add the jarring of off road & the failure is iminant.
The nuvici's seem to work....but I suspect you will see them needing a fluid change yearly on a minimum. I know of a couple of them slipping badly when used by the motored bike guys (more properly the "engine cycle" guys)
Green machine is running a new set up through a Rolloff speed hub...(which I suspect may be a mortal sin
) I am hopeful it proves to be a winner.
full-throttle
1 MW
Yeah, he must've been beaten up quite often a s a kid. Oh wait, still is. Guess there's no friendly mod to hide behind in real life.Thud said:
Anyway, I'm not impressed with Sachs 7x3 Quartz hub either. I didn't break one and have only used it for commuting without a motor. It just felt unresponsive, heavy, and the 33% reduction/gain is not all that noticeable.
Put it this way - I could get up the same hills and have the same top speed on the flats riding a singlespeed bike. So if anyone wants it cheaply to experiment with just PM me.
Cyclebutt
100 W
Chalo said:
Chalo, here's what you don't get. Most of us bought this thing fresh on the market last August. Cheapest mid-drive ever and the concept looked right, basic design is good. Later we discovered the shortcomings. So what would you have us do? Toss it in the river? I'm glad you are successful enough to simply write off $400 and time investment in a project. Personally I view that as the action of a wasteful quitter.
My project is hanging in the office while I monitor progress here. You may recall some of that build, GNG is around 1/3 of the cash invested. From a business standpoint, it's a loss. From an engineering standpoint, it's a challenge. From an educational standpoint (including YOUR technical contributions), well worth the cost. However, my business plan was shot in the leg with this project, bad investment. Not fond of salt being rubbed in that wound, thank you.
Some pretty interesting developments have come out of this kit and this thread. LightningRods's adjustable sheets, Denise's killer "No GasGas" carbon bike, and bee's 3D printing, come to mind. I've learned a good bit from this experience. You have enlightened me to many technical facts, as well. I appreciate your technical contributions, very instructive. If you could just quit throwing rocks.....
spinningmagnets
100 TW
I don't want to pile on you, Chalo. Recently one of your posts was a big help to me on a problem I was working on. I can't speak for anyone else, but for me...I often work on problems where there is no apparent upside, lots of wasted time and effort, but...it sounds odd...but I am having a lot fun here on ES working on odd things.
I showed the entire ground-up development of the friction-drive I built, as a copy of EVTodds build, trying to show how it could be done with just a hacksaw and a drill. Nobody wanted to copy it or buy one, but...I would NOT have traded the experience for anything. I really enjoyed the process, and now that I have moved too far from my work to E-bike...it has become wall-art.
I showed the entire ground-up development of the friction-drive I built, as a copy of EVTodds build, trying to show how it could be done with just a hacksaw and a drill. Nobody wanted to copy it or buy one, but...I would NOT have traded the experience for anything. I really enjoyed the process, and now that I have moved too far from my work to E-bike...it has become wall-art.
speedmd
10 MW
Momentary switch on the shift levers could also be used to soften gear shifts.
bee
100 W
The GNG was practically made for geeks like me, it works well enough out of the box but really shines with a few simple mods. If I wanted something that didn't require tinkering, I'd buy it 
I don't lose sleep over spending money when it comes to my toys, the most important thing to me is that I learn some skills in the process. I considered all the other mid-drive kits and chose the one with the largest DIY community and I have no regrets! I learned a ridiculous amount about bicycles, electric motors, and have broadened my engineering knowledge a huge amount. These skills will net me much more money in the long-run than I've invested in this kit
I was also finally able to use one of my favorite new tools, the 3d printer, to quickly and cheaply solve a problem that would have otherwise required expensive custom fabrication.
Some geeks are happy learning theory all day and spend their free time citing books and being a living, breathing, personal encyclopedia. Others only want to learn the basic necessities so they can apply their knowledge and start thinking outside of the box. I've found that for good engineering to happen it helps to have both kinds of geek on a team, creative folks tend to thrive when surrounded by people telling them something can't be done, and some criticism helps keep the creative thinking realistic.
I don't lose sleep over spending money when it comes to my toys, the most important thing to me is that I learn some skills in the process. I considered all the other mid-drive kits and chose the one with the largest DIY community and I have no regrets! I learned a ridiculous amount about bicycles, electric motors, and have broadened my engineering knowledge a huge amount. These skills will net me much more money in the long-run than I've invested in this kit
I was also finally able to use one of my favorite new tools, the 3d printer, to quickly and cheaply solve a problem that would have otherwise required expensive custom fabrication.
Some geeks are happy learning theory all day and spend their free time citing books and being a living, breathing, personal encyclopedia. Others only want to learn the basic necessities so they can apply their knowledge and start thinking outside of the box. I've found that for good engineering to happen it helps to have both kinds of geek on a team, creative folks tend to thrive when surrounded by people telling them something can't be done, and some criticism helps keep the creative thinking realistic.
LightningRods
1 MW
I think Bee has raised the best point in favor of the GNG so far. It has this development community behind it.
I ordered a fancy schmancy aluminum 18T pulley from SDI just to see what it's finish and profile look like. It just arrived. Here's a 3/4 view:
Just for comparison's sake here is the 14T GNG overlaid on the SDI 18T. Both are at 2X. Note the tooth profiles of each:
I don't know that the drive pulley needs to be this clean and this smooth, but this is the way that I want it.
I ordered a fancy schmancy aluminum 18T pulley from SDI just to see what it's finish and profile look like. It just arrived. Here's a 3/4 view:
Just for comparison's sake here is the 14T GNG overlaid on the SDI 18T. Both are at 2X. Note the tooth profiles of each:
I don't know that the drive pulley needs to be this clean and this smooth, but this is the way that I want it.
Thud
1 MW
LR,
Is your new pulley HTD?
The profile looks like GT2 to my weak eyes...
Is your new pulley HTD?
The profile looks like GT2 to my weak eyes...
LightningRods
1 MW
Thud said:
It was supposed to be HTD5. I'm thinking the same thing myself. The square bottoms look like GT2. I've already written SDI.
Not that running GT2 is a bad idea in any way.
I think the Nuvinci has a lot of other advantages. I use one on my mid-drive. Mine is 400 W (45 N*m max motor output from the bottom bracket (not including my input)).
Advantage:
Shift fast
Come off the shelf with a twist grip throttle (indexed shifters are too slow)
Come off the shelf with everything you need (Alfine, etc require shifters and all kinds of stuff - I wanted all kitted, I wish there were more options for fully built wheels)
tire removal is still okay
Have you seen this: http://www.gizmag.com/zeroed-g1-mountain-bike/18570/
A setup like this could be used to reduce the torque input to an acceptable level. Also, someday I'd like to integrate the transmission with my motor/bottom bracket/everything.
Advantage:
Shift fast
Come off the shelf with a twist grip throttle (indexed shifters are too slow)
Come off the shelf with everything you need (Alfine, etc require shifters and all kinds of stuff - I wanted all kitted, I wish there were more options for fully built wheels)
tire removal is still okay
Have you seen this: http://www.gizmag.com/zeroed-g1-mountain-bike/18570/
A setup like this could be used to reduce the torque input to an acceptable level. Also, someday I'd like to integrate the transmission with my motor/bottom bracket/everything.
flyinmonkie
10 kW
The biggest advantage of the GNG kit is the motor. Having a 1000w continuous capable motor that is the width of a bottom bracket is what makes it worth looking at. That has been the biggest thing holding up mid drives. Also, it does not have an internal gear box for those that do not like the noise of the headline (cyclone, AFT, Ego) motors.
Basically you get a solid motor, a pretty solid controller (though not programmable and a little on the week side for some), and a jackshaft for reduction for $400. The rest is a bit of a template to make a mount from, or adapt a bit to make a very solid set up.
Clay
Basically you get a solid motor, a pretty solid controller (though not programmable and a little on the week side for some), and a jackshaft for reduction for $400. The rest is a bit of a template to make a mount from, or adapt a bit to make a very solid set up.
Clay
speedmd
10 MW
Agree, most of the stuff I am remaking, redesigning or upgrading. Motor looks like a sweet spot for adapting to most light production bike frames.
For me a great plus has been that it is bringing back lots of cool early memories of my first mini bike builds. Look forward to sharing this all with the grand kids as it develops.
For me a great plus has been that it is bringing back lots of cool early memories of my first mini bike builds. Look forward to sharing this all with the grand kids as it develops.
t3sla
10 kW
Just out of curiosity has anyone been in direct contact with the gng staff about making improvements to the product?
I assume they are watching or would only hope. But are they taking notes? I'd love to see the product advance from all of this.
I assume they are watching or would only hope. But are they taking notes? I'd love to see the product advance from all of this.
spinningmagnets
100 TW
Lets look at the "most bang for your buck" mods. Add LightningRods adjustable outer sheets to get rid of the horrible stock belt idler ($40?). Swap in a #25 chain on the primary (72T:12T) for a 6:1 reduction (another $40?).
The secondary? the 12T FW is weak and will die eventually, so don't wait. skyunjae's shaft adapter is $42, and an 13T ACS-Crossfire is $18. Drill and bolt a $40 60T Vuelta chainring onto the side of the existing chainring just to make it fast and easy, so a 60:13 = 4.6:1...4.6 X 6...= 27:1 reduction, plus the weakest parts of the $400 drive are upgraded for around $180.
48V X 67-Kv = 3216-RPM
36V X 67-Kv = 2412-RPM
X our new reduction of 27:1 =
48V = 119
36V = 89
Subtract 20% because we are now moving 200+ pounds of rider/bike up a steep hill equals a pedal-cadence of =
48V = 95
36V = 71
If you have a full-suspension and don't take it on jumps (a street commuter), the stock BB should be fine. For a hardtail that jumps, upgrade the BB depending on how much of a hit your credit card can take...
edit: several builders are trying the 120T:18T pulley set, = 6.7:1 reduction = total 30.6:1 reduction.
unloaded pedal-cadence/loaded
48V = 105/84
36V = 79/63
The secondary? the 12T FW is weak and will die eventually, so don't wait. skyunjae's shaft adapter is $42, and an 13T ACS-Crossfire is $18. Drill and bolt a $40 60T Vuelta chainring onto the side of the existing chainring just to make it fast and easy, so a 60:13 = 4.6:1...4.6 X 6...= 27:1 reduction, plus the weakest parts of the $400 drive are upgraded for around $180.
48V X 67-Kv = 3216-RPM
36V X 67-Kv = 2412-RPM
X our new reduction of 27:1 =
48V = 119
36V = 89
Subtract 20% because we are now moving 200+ pounds of rider/bike up a steep hill equals a pedal-cadence of =
48V = 95
36V = 71
If you have a full-suspension and don't take it on jumps (a street commuter), the stock BB should be fine. For a hardtail that jumps, upgrade the BB depending on how much of a hit your credit card can take...
edit: several builders are trying the 120T:18T pulley set, = 6.7:1 reduction = total 30.6:1 reduction.
unloaded pedal-cadence/loaded
48V = 105/84
36V = 79/63
LightningRods
1 MW
t3sla said:
Yeah, I'm thinking about writing to tell them to steal my adjustable sheets idea. :lol: Honestly, I keep waiting for it.
I had a forum member write me recently to say that GNG was going to 'improve' the Gen 1 kit. I was interested to see what they would do. A proper motor drive pulley? Adjustable sheets? They put a plastic guard on the motor to 'waterproof' it.
I heard back from SDP about the GT2 pulley they sold me as a HTD. Not the response I was hoping for:
It's difficult unless you scan the profile at 200%. Then it's pretty frikken easy! Now I have to decide whether to send them the pic again with Gates belt profiles to try to persuade them. Another thing about SDP. The pulley was $8. Their shipping and handling charges were $30! And that was for 3rd Day UPS.
LightningRods
1 MW
The difference between HTD and GT2:
It will be very interesting to see whether SDP admits their mistake at this point or continues trying to b.s. me.
It will be very interesting to see whether SDP admits their mistake at this point or continues trying to b.s. me.
Thud
1 MW
The good news is HTD belt will run on GT2 tooth profiles....not optomly but not destructivly either....
GT2 belts will not run on HTD pulleys without creating havock.
I like every thng about SDP except the pricing....toothed belts are just expensive in the big picture.
GT2 belts will not run on HTD pulleys without creating havock.
I like every thng about SDP except the pricing....toothed belts are just expensive in the big picture.
LightningRods
1 MW
Holy hell! Get a load of this attitude!
I can't believe they're going for the "bad customer" defense!
I can't believe they're going for the "bad customer" defense!
Thud
1 MW
I stand corrected...(i knew it was one or the other)
Thanks Miles.
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