GNG, 1000W 48V BB-drive, $400

[crossbreak]

Has 50mm long x 80mm diameter rotor, small lams (quite rusted on mine...) big phases to boot and 120mm inner case diameter

150€ shipped via air mail is not bad at all!

Awesome, it has 12magnets! What means small lams? 0.3mm? Any info about KV and no load current?

114mm is a little wide though. still doable. If it is as good as it sounds, this will be my first single speed, single reduction reardrive motor... my Shimano hub with 219 sprocket adapter is still waiting for a proper engine.

 

[LightningRods]

As soon as I have the small block scratch built kit completed and available I'm going to start work on the 100mm big block kit. Initially I'm going to focus on bikes with 100mm BBs like fat bikes and big downhill bikes. I think I'm going to have to produce both a BB drive kit (basically a wide, big motor version of my current small block kit) and also a two stage direct drive. My plan is to have a primary stage that goes from the motor to a jackshaft with freewheel, and then from that jackshaft to the rear wheel on the left side. The BB and derailleur will not be involved.

I'm actually not sure which approach will work better. The big block is too powerful for bicycle drivelines if you really let it off of it's leash. If you run it direct drive with only one gear you give up a lot of the advantages you gained with more power. But once the big motor is up and running in that one gear- watch out.

 

[LightningRods]

Still waiting...

All I need are lockrings for the jackshaft and the upper frame mount. The drawings for both went in to the laser shop today. I was told next Tuesday for parts. All of the production jigs for jackshafts are done and the first three are finished. Very time consuming at this point but I'm sure production will get faster with repetition.

I have other accessories like drive enclosures on the drawing board but they are not essential. I will be releasing more goodies and add-ons for some time. The basic scratch built will be rolling off of the assembly line next week. Watch electricbike.com for upcoming reviews and a hillclimb shootout.

Here is a shot of the upper drive section of LightningRods mid drive # 000001 showing the new jackshaft housing and adjusters. This one will be going to Eric at electricbike.com. The lockrings will go on the threaded ends of the housing to clamp everything securely together.

 

[crossbreak]

a smaller pitch on these threads would help to keep the tension on the nuts. I have great success with the 12mmx1,25mm nuts, it doesn't loosen with locktite. You may get problems even with lockite on this great thread pitch :?

edit: i think of the shaft, the chain/belt tenisioner is fine like that. Really good design.

 

[LightningRods]

a smaller pitch on these threads would help to keep the tension on the nuts. I have great success with the 12mmx1,25mm nuts, it doesn't loosen with locktite. You may get problems even with lockite on this great thread pitch :?

edit: i think of the shaft, the chain/belt tenisioner is fine like that. Really good design.

I'm glad that you like the design Crossbreak. Which threads were you concerned about? The M6 bolts on either side of the jackshaft? Those are 1.0mm pitch which is standard for M6. I don't really have a lot of options there. The nuts are nyloc insert so hopefully that will keep them tight. The jackshaft housing is 24 tpi, again a standard thread.

I've come at securing the tension from so many directions here that hopefully if the suspenders break, the belt will hold the pants up. :wink:

 

[crossbreak]

the jackshaft holdings are fine, the M6x1 shaft screws concern me. There is a lot of vibration on the shaft, that is why they might loosen... most engineers chose a fine pitch thread in this situation. Locktite will do the job hopefully.
M6x0.75 would have done the job better IMO even if that one is not the common standard... it's not a big deal to buy them on ebay for example.. as said even with fine pitch 12x1.25mm nuts I got problems, solved only with locktite.

the GNG is a good example of a product that uses great parts that are horribly fit. Great that there is someone who cleans up this mess

 

[dan974]

If someone is searching for a big block GNG style motor, this seems to be a good solution (just received and mesured)
http://e-bike-diffusion.com/index.php?module=produit&prd_id=509&url_retour=http%253A%252F%252Fe-bike-diffusion.com%253A80%252Findex.php%253Fmodule%253Dcategorie%2526code_cat%253D24%2526page_start_num%253D1

Has 50mm long x 80mm diameter rotor, small lams (quite rusted on mine...) big phases to boot and 120mm inner case diameter

150€ shipped via air mail is not bad at all!

shipped from marseille or HongKong ? looks like your next project is on tracks
tiens tiens... http://e-bike-diffusion.com/index.php?module=produit&prd_id=531

 

[acer]

bump

Hi,

first time poster looong time reader
I am going for my first build and am trying to decide on my components

Live in hilly region, would like to use GNG for dual purpose, hilly commute and have some fun on trails (nothing hard core)

As concerning commute, what Wh/Km (Wh/mi) can I expect being easy on throttle going 20mph on flat

What is better for efficiency : 48V at 15A vs 72V at 10A (or for trails: 48V at 30A vs 72V at 20A)

For battery am thinking of Lifepo4 Headways (have fear from Lipo) but not decided yet on voltage and Ah
Please comment
Thnx, Alen

 

[crossbreak]

bump

Wasn't this discussed many times before? choosing higher or lower voltage is no question specific to the GNG. The GNG is not so much less efficient than a hub on the flats. Simply use the ebikes.ca/simulator to calc your range. Just add 20% of battery to be sure.

I made an example picture for you. This is really simple, give it a try!

 

[Joe T.]

I'm actually not sure which approach will work better. The big block is too powerful for bicycle drivelines if you really let it off of it's leash. If you run it direct drive with only one gear you give up a lot of the advantages you gained with more power. But once the big motor is up and running in that one gear- watch out.

In my mind choosing a mid drive over a hub motor is the luxury of gear changing on the fly. Weight distribution aside, if you will be on roads and side streets only, why not take the simple approach and go hub motor?

I may be in the minority on this.

 

[acer]

thank you crossbreak, I will try the simulator, was searching but unable to find discussion regarding voltage or amps

bump

Wasn't this discussed many times before? choosing higher or lower voltage is no question specific to the GNG. The GNG is not so much less efficient than a hub on the flats. Simply use the ebikes.ca/simulator to calc your range. Just add 20% of battery to be sure.

I made an example picture for you. This is really simple, give it a try!

 

[crossbreak]

In my mind choosing a mid drive over a hub motor is the luxury of gear changing on the fly. Weight distribution aside, if you will be on roads and side streets only, why not take the simple approach and go hub motor? I may be in the minority on this.

Still there is not only the luxuries of changing gears+lightweight wheel. Heat sinking is another thing. An enclosed hub is horribly cooled, it can overheat within minutes even if the motor could last the power easily. The well cooled middrive motors are different, you can have a 1kg motor with 1kW continuous, no porblem. Show me a hub that can do this Most geared hubs that have a 1kW motor like the Bafang SWXH (~1.3kg just the bare motor without gears, hub etc.) could to 1kW easily, but it overheats at 500W when enclosed in a hub.

The big block is too powerful for bicycle drivelines if you really let it off of it's leash. If you run it direct drive with only one gear you give up a lot of the advantages you gained with more power. But once the big motor is up and running in that one gear- watch out.

Single speed has one big advantage: It's unbeatable lightweight and simple. A bigblock singlespeed could weight the same as the stock GNG unit, but would beat it's performance several times. Bare motor+chain are only 6kg, almost the same as the GNG unit. No freewheel cranks save some more weight... and so on.

 

[silence]

Any info about KV and no load current?

Info from ebay.

 

[LightningRods]

In my mind choosing a mid drive over a hub motor is the luxury of gear changing on the fly. Weight distribution aside, if you will be on roads and side streets only, why not take the simple approach and go hub motor?

Weight distribution is no small thing. Even more important, especially on FS bikes, is unsprung weight. Having a heavy hub motor in your wheel makes the suspension so slow to react to bumps that it's far less effective. Hub motor bikes used on rough terrain have wheel problems. So if better weight distribution and lower unsprung weight is all you get with mid drive over a hub setup I still think it's well worth it. The way things are shaping up is hub motors for simple installs on bikes used on smooth, not overly hilly streets and mid drives for off road and hilly terrain. I'd have a hub drive beach cruiser but that's about it.

I do agree that having at least three speeds is an advantage. Customers are writing asking for both BB drive and direct drive so we'll try them both and see which works best.

 

[Joe T.]

Hi,

first time poster looong time reader
I am going for my first build and am trying to decide on my components

Live in hilly region, would like to use GNG for dual purpose, hilly commute and have some fun on trails (nothing hard core)

As concerning commute, what Wh/Km (Wh/mi) can I expect being easy on throttle going 20mph on flat

What is better for efficiency : 48V at 15A vs 72V at 10A (or for trails: 48V at 30A vs 72V at 20A)

For battery am thinking of Lifepo4 Headways (have fear from Lipo) but not decided yet on voltage and Ah
Please comment
Thnx, Alen

When I built my bike last summer all I wanted to worry about was the bike. I didn't want anything to do with learning all about batteries and power consumption or anything complicated. Mike at Rad Power Bikes suggested a 48V 10ah eZee flat battery. I bought it and never looked back. Maybe there is room to save money but I didn't have the time to spare.

I run an out of the box GNG 450W kit. Nothing fancy. Never messed with anything to get power. I get 2 days riding in the woods and rail trails. It goes up hills great and I can go 20+ miles through the trails and not even think of running out of battery. I peddle when there is any work to be done but on flat ground I just motor along. Usually I conserve battery in the early part of my ride and at the end I push the battery if I want. If it cuts out from low voltage I just peddle along and save the motor for the hills. I recovers enough to get me home.

 

[crossbreak]

Info from ebay

thx for this figure. It tells me that for a 74V/20s Lipo setup I will need a 4:1 reduction. A 13T Freewheel and a 52T sprocket should do the job.

I read 34.7KV for this BIG Block alternative from your graph.

Max speed around 60kph, max hill climb gain of 30.6% or 17° for 40A battery and 100A phase current. This means it will output 28Nm of torque at the shaft at 100A Phase current Nice figures... I think I will go for it.

Edit: In this 4:1 geared config it should behaves like a geared hub drive with 8.7KV. So equal to a BMC V_1 (it has about the same weight and 8.4KV geared in the ebikes.ca simulator).

A BMC V1 has more magnets and more reduction, but I guess it has less copper. So this single speed config should behave the same in the simulator, except-> it will barely overheat

this is a graph for 72V and 40a of the BMC V1

 

[crossbreak]

the advatages over a CA120 motor I see are:
-low KV, low pole count -> compatible to normal ebike controllers
-slower, less noisy
-enclosed, passive cooling is suitable

Drawbacks:
-more heavy, bigger
-less efficient

 

[crossbreak]

ok now I compare BMC_v1 and this GNG big block alternative geared 4:1 @48V. Both at 270rpm ...which one is "bigger"?? Which one has more torque at this rpm?? they have about the same KV.

the big block alternative has 60Nm. The BMC_V1 has 45Nm. Seems like it is "weaker"

 

[crossbreak]

summing up: this seems to be a good motor.. not only for those who wanna go single speed/single reduction. I actually hate messing OT in threads but this came up fast... i'd like to proceed discussion about this new GNG BIG BLOCK alternative in a new thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483

 

[Grey beard]

While you are designing your left side big block drive, this guys ICE powered bike uses an interesting jackshaft drive.
The drive pic is about bottom of the page, and btw, I'm interested in what you come up with.
http://motorbicycling.com/showthread.php?t=52933&page=3

 

[LightningRods]

While you are designing your left side big block drive, this guys ICE powered bike uses an interesting jackshaft drive.

I LOVE these Sportsman bikes! I've always had a weakness for board track racers. I also like the electric Juicer (http://emotorbicycle.com/) although it's not done exactly as I'd do it. This particular Sportsman is beautifully put together.

Using the BB axle as the jackshaft is a fairly tidy solution. As Crossbreak pointed out on the GNG Gen 2 thread, as long as you have your chains running in a straight line the torsional forces cancel each other out. The pull on the motor chain and final drive chain are equal and in opposite directions.

Thanks for pointing out this solution. It would even work on cluttered FS bikes which are always a packaging problem.

 

[Grey beard]

I love Pat's work. I've quite a few pieces built by him, and they are so good looking you want to sit and fondle them.
Glad you appreciated it.

Mike

 

[notger]

hi

does anyone of you know this effect, that the bikes drive chain gets "eaten" wraped around the shifting-chainrings ?

I know that dirty sandy and frozen chains cause these problems but i just put a new chain on and in most cases i drive uphill with one of the smaller chainring 22t or 33t and the chain gets wraped around the chainring. (i have 4 chainring 3 for shifting and one for transfering the power from the gng)

So it does not follow the line back to the sprockets.

this did never happen on a leveled course or with the big 44 t chainring

i allready tried the bionicon c.guide but it got destroied after a few "chain wraps"

anyone with the same experience? an some ideas what do do about it?

thanks

 

[boltedjolt]

Might have too many links. I had the same problem removed 4 link to tighten things up and that did the trick.

 

[notger]

i also thought of that, but i already have too less links i cannot chift to the position biggest sprocket and biggest chainring anymore, wich i anyway would never do