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

[_Tommy_]

This is a good design. I just want to make the point for people considering making something similar that belt drives benefit more from longer center to center distances than chains do. If you use an engineering application or a belt drive design program you'll see that there is a minimum recommended distance. The stock GNG drive does not meet this distance requirement.

Is that to ensure the pitch allows for maximum teeth engagement belt-to-pully?

i.e. less center-to-center distance increases the angle of belt-to-pully, reducing the #teeth engaged? Farther away reduces that angle on your drive cog?

Exactly. I wonder though how much influence it actually has on the teeth engagement if you increase the center to center with, lets say 20-30mm. I have a feeling you have to increase it quite much to get a noticeable benefit, but I could be wrong.

I still agree with LightningRods that you should put them further apart if possible. The belt drive seems to be one of the bigger weak points on the kit.

 

[_Tommy_]

I actually was able to do a short test run yesterday. The weather wasn't the best (-23°C/-9°F) so I only tested it for about 100m. Everything worked good but the motor felt quite weak. I hope it was because of the snow and low tire pressure. I noticed after the test that both the belt and the chain needed to be tensioned. I hope it was just because of some screws that wasn't properly tightened.

I was going to wait with posting until I had better pictures to show you, but here you go. It will be better looking when I have painted the plates. They are just made out of some junk I found in my dads garage. It is amazing how good precision you can get with an angle grinder, bench grinder, dremel, drill and alot of patience.

 

[LightningRods]

This is a good design. I just want to make the point for people considering making something similar that belt drives benefit more from longer center to center distances than chains do. If you use an engineering application or a belt drive design program you'll see that there is a minimum recommended distance. The stock GNG drive does not meet this distance requirement.

Is that to ensure the pitch allows for maximum teeth engagement belt-to-pully?

i.e. less center-to-center distance increases the angle of belt-to-pully, reducing the #teeth engaged? Farther away reduces that angle on your drive cog?

Yes that's exactly right. The farther apart they are the less their size difference matters.

You can see the reduced wrap on the driver pulley in the image with the shorter center to center distance. The wrap on the larger driven pulley does the opposite: as the center to center increases the wrap diminishes. But there are so many teeth engaged on the driven that it doesn't matter. It's always the driver that skips.

These factors reduce the number of teeth in engagement:
Lower tooth count driver
Higher tooth count driven
Shorter center to center distance

These factors increase the number of teeth in engagement:
Higher tooth count driver
Lower tooth count driven
Greater center to center distance

All three factors affect each other. You can make up for too few teeth on the driver relative to the driven by increasing the center to center distance. If you have limited space, you're not going to be able to get as much reduction.

 

[LightningRods]

I actually was able to do a short test run yesterday.

Looks great Tommy! A very tidy install.

I ran the stock GNG 14t/80t pulley combination through a belt drive designer. The minimum center to center distance for that pulley combination is 9.4 inches. The stock GNG center to center is 3 3/4 inches! Even if the GNG driver pulley weren't badly made the drive would still have skipping problems.

 

[rodgah]

that looks great _tommy_

Can you spin the shock 180 in its mounts so the dampening adjuster is rearward? It looks from the photos like you could tighten up the tolerances and get the motor and jackshaft lower in the frame leaving a bigger gap at the top for batteries. Many things can be accomplished with patience.

 

[crossbreak]

what about weight distribution? rides much better when the COG is low... anyway you have plenty of room for battery there now

 

[_Tommy_]

I actually was able to do a short test run yesterday.

Looks great Tommy! A very tidy install.

I ran the stock GNG 14t/80t pulley combination through a belt drive designer. The minimum center to center distance for that pulley combination is 9.4 inches. The stock GNG center to center is 3 3/4 inches! Even if the GNG driver pulley weren't badly made the drive would still have skipping problems.

I guess that is one of the reasons why they have the tensioner on the stock kit. It looks like with the tensioner you will have about 50% of the teeth engaged, which is more than you can get by increasing the distance. Too bad it takes alot of energy.
https://sofehq.dm1.livefilestore.co...YVI6xQukC3XpG3_FtE/WP_20131107_001.jpg?psid=1

How about your pulleys? Same distance needed with those?

 

[_Tommy_]

that looks great _tommy_

Can you spin the shock 180 in its mounts so the dampening adjuster is rearward? It looks from the photos like you could tighten up the tolerances and get the motor and jackshaft lower in the frame leaving a bigger gap at the top for batteries. Many things can be accomplished with patience.

Actually the dampening adjuster isn't the first thing to hit the motor assembly. At first I thought that it would be too. That is why I removed the cooling fins on one side of the motor. Turns out that it is the rocker arm hitting one of the flanges on the motor end plate.

 

[_Tommy_]

what about weight distribution? rides much better when the COG is low... anyway you have plenty of room for battery there now

From the COG point of view it would be a good to have the batterys underneath the frame. They would have to be very well protected though. At the moment I have 4*5000mAh 6S longpacks in a backpack.

 

[Gab]

Tommy

It is hard to get at stealthy look with this kit wherever you put it. If you want a stealthy mid drive kit I think it's better to go with the cyclone kit, which has planetary gears instead of the jackshaft. However I have read that Cyclones are quite noisy. That's why I chose GNG.

Yeah Tommy i agree the exposed gears and chains/belts with GNG makes it very hard to hide the kit, as you say the cyclone with the planetary gears instead of the jackshaft is a lot more compact and stealthy looking. With the noise of the cyclones, from what i have read on the sphere it seems to be the worst of the noise is caused when people run 48v and grease in the gearboxes and the teeth are munching on each other and wearing out fast. People who have used oil have reported the gearbox lasts a lot longer as the gears are lubricated better and this also would make sense that their is less noise.


Some discussion on this here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=34421

Re: Removing cyclone gearbox
Postby oigoi » Thu Jul 19, 2012 8:27 am

I have made mine a lot quieter by pulling out most of the grease and sticking a bit of gear oil (90 viscosity) in it. not a lot of oil, 1 or 2 tablespoons

Re: Removing cyclone gearbox
Postby boostjuice » Thu Jul 19, 2012 1:35 pm

I to am using gear oil in my Cyclone gearbox both for noise reduction and hopefully to extend the life of the gears. Performing this modification certainly quietens down the gear whine compared with the overly thick factory Molybdenum disulphide based grease that gets pushed out from between the gear teeth quite quickly.

 

[LightningRods]

I guess that is one of the reasons why they have the tensioner on the stock kit. It looks like with the tensioner you will have about 50% of the teeth engaged, which is more than you can get by increasing the distance. Too bad it takes alot of energy.
https://sofehq.dm1.livefilestore.co...YVI6xQukC3XpG3_FtE/WP_20131107_001.jpg?psid=1

How about your pulleys? Same distance needed with those?

The idler on the stock GNG absolutely is an attempt to cheat the tooth engagement issue. In addition to being noisy and sucking power it backbends the belt and breaks the reinforcement layer in the belt. I had a forum member write me this week saying that in freezing weather his belts have a much shorter life span on his stock GNG because they are less tolerant of backbending when cold.

The center to center on my 18 tooth/90 tooth GT pulley combo is 4.7 inches. It's also 66% wider than the 15mm GNG pulley at 25mm. Overall it has 4x the power capacity of the stock GNG drive with idler.

 

[spinningmagnets]

Here's a graphic to show the extreme back-bending on the primary belt:

 

[r3volved]

I had a forum member write me this week saying that in freezing weather his belts have a much shorter life span on his stock GNG because they are less tolerant of backbending when cold.

That was me in the cold. Snapping belts at -20C with less than 200km
I ordered a whole bunch

 

[heathyoung]

When are you making your 18/90T pulleys available for the masses?

I couldn't see them on the website.

 

[Somebodystopme!!]

So I bought a chain drive 48V 450W version from GNG and am using LR's sheets so I can get rid of that horribly noisy tensioner.

When using LR's sheets the stock chain becomes too short. I "assumed" that the chain was #219.

However I have not read a straightforward answer as to what type of chain actually comes with this.

Note the stock chain versus the new #219 chain i just bought. 11T primary sprocket fits OK but the larger sprocket is not OK.



So what is the chain that comes stock? Where can I buy new primary sprockets? (Motor and Jackshaft)

View attachment 3

View attachment 1

 

[Somebodystopme!!]

I guess that is one of the reasons why they have the tensioner on the stock kit. It looks like with the tensioner you will have about 50% of the teeth engaged, which is more than you can get by increasing the distance. Too bad it takes alot of energy.
https://sofehq.dm1.livefilestore.co...YVI6xQukC3XpG3_FtE/WP_20131107_001.jpg?psid=1

How about your pulleys? Same distance needed with those?

The idler on the stock GNG absolutely is an attempt to cheat the tooth engagement issue. In addition to being noisy and sucking power it backbends the belt and breaks the reinforcement layer in the belt. I had a forum member write me this week saying that in freezing weather his belts have a much shorter life span on his stock GNG because they are less tolerant of backbending when cold.

The center to center on my 18 tooth/90 tooth GT pulley combo is 4.7 inches. It's also 66% wider than the 15mm GNG pulley at 25mm. Overall it has 4x the power capacity of the stock GNG drive with idler.

Any idea when these will be available???????

 

[pollux]

I am lost, This forum has so much info but breaking it down into something that makes sense to me is very frustrating. I do not know where this message will go or even if it will go anywhere is beyond me, but thanks to all. The struggle to understanding your tech talk was worth it. I now know what the components required to build a quadcopter mean.
peace

 

[LightningRods]

When are you making your 18/90T pulleys available for the masses?

I couldn't see them on the website.

I did a limited release of pulleys to a handful of customers to see how things went. I want to tighten up a couple of things in the 18 tooth driver before sending dozens all over the planet. If I have to send replacement parts internationally it gets expensive for me. I'm making new molds right now and hope to have near perfect pulleys to ship by weeks end.

I will continue to improve all of my parts based on the feedback I get from Forum members.

 

[LightningRods]

So I bought a chain drive 48V 450W version from GNG and am using LR's sheets so I can get rid of that horribly noisy tensioner.

When using LR's sheets the stock chain becomes too short. I "assumed" that the chain was #219.

Note the stock chain versus the new #219 chain i just bought. 11T primary sprocket fits OK but the larger sprocket is not OK.

So what is the chain that comes stock? Where can I buy new primary sprockets? (Motor and Jackshaft)

I also assumed that it's #219 because it's too large for #25 (.25" pitch) and too small for a #35 (.375" pitch). I put the calipers on the GNG chain and came up with around .315". #219 is .300", the closest to this oddball but no fit. Has anyone ever heard of a .315" pitch chain??

My secondary #219 sprocket set meant to bolt onto the BB will also bolt right onto the hub on the 60v kit. You can use my adapter plate and have any 219 sprocket tooth count from 64 to 93. It wouldn't be hard to adapt my 12 tooth 219 secondary driver to the motor shaft of the 60v. If there's enough interest I'll make it available.

 

[skyungjae]

I am lost, This forum has so much info but breaking it down into something that makes sense to me is very frustrating. I do not know where this message will go or even if it will go anywhere is beyond me, but thanks to all. The struggle to understanding your tech talk was worth it. I now know what the components required to build a quadcopter mean.
peace

You might want to create your own thread, and post what you're interested in doing. The members here are really great at pointing you in the right direction. A year ago, I was the same... saw a few factory e-bikes at a local retailer... I wasn't impressed. Anything that did impress me was sooooo incredibly out of my price range, my only option was to put something together.

 

[deepfraught]

When are you making your 18/90T pulleys available for the masses?

I couldn't see them on the website.

I did a limited release of pulleys to a handful of customers to see how things went. I want to tighten up a couple of things in the 18 tooth driver before sending dozens all over the planet. If I have to send replacement parts internationally it gets expensive for me. I'm making new molds right now and hope to have near perfect pulleys to ship by weeks end.

I will continue to improve all of my parts based on the feedback I get from Forum members.

Over a year now I've had this kit and not yet fitted, so I'm willing to hang on for another week before it turns the first pole in anger =D

 

[justlooking]

I actually was able to do a short test run yesterday. The weather wasn't the best (-23°C/-9°F) so I only tested it for about 100m. Everything worked good but the motor felt quite weak. I hope it was because of the snow and low tire pressure. I noticed after the test that both the belt and the chain needed to be tensioned. I hope it was just because of some screws that wasn't properly tightened.

I was going to wait with posting until I had better pictures to show you, but here you go. It will be better looking when I have painted the plates. They are just made out of some junk I found in my dads garage. It is amazing how good precision you can get with an angle grinder, bench grinder, dremel, drill and alot of patience.

View attachment 1

turn your controller up the other way up, all the rain will get in where the wires enter it

 

[silence]

Has anyone ever heard of a .315" pitch chain??

Yes.
ISO chain 05-B1 has 8mm pitch which is ~.315".

edit:

There is also chain called T8F, beefier than 05B and with straight side plates.
Often used in karts and minimotos.

 

[LightningRods]

ISO chain 05-B1 has 8mm pitch which is ~.315".

There is also chain called T8F, beefier than 05B and with straight side plates.
Often used in karts and minimotos.

Thanks Silence. It looks like it is T8F. Here's a source:

http://tncscooters.com/index.php?route=product/category&path=38_104

I looked around some more on this site. Here are some replacement driver sprockets that should fit the 60v! The quality even looks decent!

http://tncscooters.com/index.php?route=product/category&path=63_93

 

[LightningRods]

Also higher tooth count driven sprockets that should bolt right on:

http://tncscooters.com/index.php?route=product/category&path=63_92

They have 63 tooth and 72 tooth sprockets to replace the provided 54 tooth (which seems to be here too). So much for me making a 219 replacement kit for the 60v. This is a Chinese cheap fix that should work. I'd go for the 13 tooth driver for quieter operation and longer chain life and then get the biggest driven sprocket that would fit my bike.