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

[speedmd]

I went with a 12/72 #25 chain. Thick oil/ fluid film/ motor cycle chain oil makes it not too noisy. 11 is a bit more lumpy and may ring a bit more. Give it a whirl. You can put all the power it will make into it now.

Hey "D" WOW. Love the "no GAS GAS". What a trip. Nice glass work. Need to get some more epoxy and play a bit more and make some of those fine looking chain guards and finish my battery box so it is presentable.

cheers

 

[skyungjae]

These chain drive conversions look so tempting despite my belt longevity. :wink:

Hey Mike (LightningRods), have you abandoned the custom output shafts for a reversible chain drive and the 25mm belt?

 

[Denisesewa]

I went with a 12/72 #25 chain. Thick oil/ fluid film/ motor cycle chain oil makes it not too noisy. 11 is a bit more lumpy and may ring a bit more. Give it a whirl. You can put all the power it will make into it now.

Hey "D" WOW. Love the "no GAS GAS". What a trip. Nice glass work. Need to get some more epoxy and play a bit more and make some of those fine looking chain guards and finish my battery box so it is presentable.

cheers

Hey, Thanks "MD" , After a couple hundred miles of hard riding the chain drive gets very quiet, I'd say comparable to the belt , I use " Chain wax " for lube as its tenatious although a bit of a pain to clean up when the time comes.
"D"

 

[speedmd]

I use " Chain wax " for lube as its tenatious although a bit of a pain to clean up when the time comes."D"

That is what you use "GAS GAS" for! Outside always!

cheers

 

[Denisesewa]

I use " Chain wax " for lube as its tenatious although a bit of a pain to clean up when the time comes."D"

That is what you use "GAS GAS" for! Outside always!

cheers

Ha ! Too funny !!!

 

[Secret1511]

I went with a 12/72 #25 chain. Thick oil/ fluid film/ motor cycle chain oil makes it not too noisy. 11 is a bit more lumpy and may ring a bit more. Give it a whirl. You can put all the power it will make into it now.

Hey "D" WOW. Love the "no GAS GAS". What a trip. Nice glass work. Need to get some more epoxy and play a bit more and make some of those fine looking chain guards and finish my battery box so it is presentable.

cheers

Hey, Thanks "MD" , After a couple hundred miles of hard riding the chain drive gets very quiet, I'd say comparable to the belt , I use " Chain wax " for lube as its tenatious although a bit of a pain to clean up when the time comes.
"D"

Ok good to hear. Just put my controller op to 60a.( I think this is the max for a modded 9fet). What a difference. No belt skipping.

 

[Kingwouldbe]

Well got my bike running, went around the neighborhood and the chain did not come off.

I just ordered my upper and lower sheets from Lightning rods ( Mike), what a great guy to deal with, looking forward to his pulleys, in a week or 2

 

[LightningRods]

These chain drive conversions look so tempting despite my belt longevity. :wink:

Hey Mike (LightningRods), have you abandoned the custom output shafts for a reversible chain drive and the 25mm belt?

Hey John- No I haven't abandoned the custom motor spindles at all. My friend who does my old school machine work for me is moving 900 miles with his machine shop to team up with me and build bikes. I will be importing both the 'GNG' motor and the loose motor spindles direct from the manufacturer. Customers will be able to buy a motor with the output shaft of their choice or a custom shaft set up for their existing motor. I'm going to focus on 12mm shaft diameter because I agree with Spinningmagnets that 12mm should be the standard. We will be setting up shop the end of August.

I have to wonder if all of the twiddling with the primary drive on the GNG isn't a big part of it's appeal. I posted in the Gen 2 (planetary primary) thread that I had made adjustable BB sheets for the Gen 2 and I've mostly been hearing crickets. By contrast I've almost completely sold out of the 73mm BB sheets for the Gen 1 and I'm ordering another run today. Clearly people are a lot more excited about the Gen 1x.

I completely understand why some of you have gone to #25 primary chain and I see the logic in it. I just have a personal preference for belt drive for the primary side. I think that 20mm wide GT2, which has about 260% the power capacity of 15mm wide HTD, is going to be perfect for the GNG. Add to that 18 teeth on the driver instead of 14 and an accurate tooth profile instead of holes bored into a steel cylinder as GNG did it, and I think we have this whipped. We should see next week when I start pouring 95 tooth and 120 driven pulleys.

 

[comradegerry]

Some of the finest RC reduction drives around, that Matt "Recumpence" has created, use a primary belt and secondary chain setup. There is sound reason, practical realworld experience and considered logic behind his choices.

You are barking up the correct tree.

Look forward to seeing how the big plastic pulleys cast.

By the time you are finished, you really will have made a "silk purse out of a sow's ear"

 

[skyungjae]

These chain drive conversions look so tempting despite my belt longevity. :wink:

Hey Mike (LightningRods), have you abandoned the custom output shafts for a reversible chain drive and the 25mm belt?

Hey John- No I haven't abandoned the custom motor spindles at all. My friend who does my old school machine work for me is moving 900 miles with his machine shop to team up with me and build bikes. I will be importing both the 'GNG' motor and the loose motor spindles direct from the manufacturer. Customers will be able to buy a motor with the output shaft of their choice or a custom shaft set up for their existing motor. I'm going to focus on 12mm shaft diameter because I agree with Spinningmagnets that 12mm should be the standard. We will be setting up shop the end of August.

I have to wonder if all of the twiddling with the primary drive on the GNG isn't a big part of it's appeal. I posted in the Gen 2 (planetary primary) thread that I had made adjustable BB sheets for the Gen 2 and I've mostly been hearing crickets. By contrast I've almost completely sold out of the 73mm BB sheets for the Gen 1 and I'm ordering another run today. Clearly people are a lot more excited about the Gen 1x.

I completely understand why some of you have gone to #25 primary chain and I see the logic in it. I just have a personal preference for belt drive for the primary side. I think that 20mm wide GT2, which has about 260% the power capacity of 15mm wide HTD, is going to be perfect for the GNG. Add to that 18 teeth on the driver instead of 14 and an accurate tooth profile instead of holes bored into a steel cylinder as GNG did it, and I think we have this whipped. We should see next week when I start pouring 95 tooth and 120 driven pulleys.

Fantastic. I think I'm gonna have to wait and do a whole new build.

 

[speedmd]

Problem from the start has been little to no choices on the big belt pulley side. # 25 and 219 sprockets are much more common. Solve this and belt should win out as long as a suitable idler set up is part of the solution.

 

[rodgah]

I posted in the Gen 2 (planetary primary) thread that I had made adjustable BB sheets for the Gen 2 and I've mostly been hearing crickets.

I think it is probably that the gear ratio is variable with the gen 1, and that there is a consensus that the gen2 will strip its planets very quickly with more power. I really like the gen2 for its robust sealed nature and simplicity, adding your 219 sprocket is just icing on the cake for that kit if the stock system fits your needs. I would really like to know the sound difference between it and a cyclone, as the cyclones are obnoxiously loud which would be a deal killer for most people I am sure, and also a destruction test of exactly what power it could take reasonably before it eats itself. Even a back to back test between it and a gen1 would be handy info. Personally I think it has been ignored too early as I have yet to read anyone breaking one....but I could be wrong.

A cover, however light weight, for the belt/chain 1st reduction on the gen1 would really top it off, and probably fairly necessary for those of us who ride off road with the new epoxy sprockets as I dont think it would take much in the way of debris in between the belt and sprocket to ruin your day.

Problem from the start has been little to no choices on the big belt pulley side. # 25 and 219 sprockets are much more common. Solve this and belt should win out as long as a suitable idler set up is part of the solution.

there has always been choices on the belt side......
http://www.electricscooterparts.com/beltcogs.html
but you were limited by the motor output shaft. With the correct belt tension you wont need an idler on the first stage with a 20mm wide belt. Actually even just the new addon pulley for the motor output shaft from lightning rods, and the 120t freewheeling pulley from electric scooter parts and 15mm wide belt might be enough for those running stockish power levels without an idler. But for overhead shock loading you would be far better off with a 20mm wide kit.

 

[speedmd]

Larger chain sprockets commonly jump in 2 tooth increments. Scooter parts is only listing larger pulleys 15mm wide and they are jumping 15 -25 Tooth increments making it a issue for some trying to dial in ratios. Without the added wrap the idler allows, you are limited to a very small number of teeth on the small sprocket when running next to a large one and I don't think the 15mm would hold up long if pushed hard. Fine for a while if you baby it.

 

[LightningRods]

Some of the finest RC reduction drives around, that Matt "Recumpence" has created, use a primary belt and secondary chain setup. There is sound reason, practical realworld experience and considered logic behind his choices.

You are barking up the correct tree.

Look forward to seeing how the big plastic pulleys cast.

By the time you are finished, you really will have made a "silk purse out of a sow's ear"

Man, there is such a rich vein of exciting posts here that I'm going to respond one by one. I don't want to overlook anything.

Matt Schumacher does fantastic work. What Matt figured out was that the high speed primary is what makes most of the noise. It's the speed of the chain that makes the racket, not the load. So after the belt primary slows the drive speed down about 6x, chain is fine. At that point torque has been multiplied 6x and raw strength is more of an issue. Also a wide belt in the bottom bracket would take up too much space.

The urethane resin I'm using is a special formulation that is meant for high impact, high shear applications. It's pricey ($150 a gallon) but seems to be the stuff. Once it cures it is super tough. I have a gallon coming on Wednesday to pour big pulleys.

The rest of you should know that Comradegerry here sent me a few hundred dollars to help with development just to make this happen for everyone. What an incredible group of people Endless Sphere is. I've never seen anything like this. If the entire world ran this way, it would work.

 

[LightningRods]

Fantastic. I think I'm gonna have to wait and do a whole new build.

See how smart you've been nursing that stock GNG stuff all this time? Now you're ready to upgrade!

 

[LightningRods]

Problem from the start has been little to no choices on the big belt pulley side. # 25 and 219 sprockets are much more common. Solve this and belt should win out as long as a suitable idler set up is part of the solution.

Larger chain sprockets commonly jump in 2 tooth increments. Scooter parts is only listing larger pulleys 15mm wide and they are jumping 15 -25 Tooth increments making it a issue for some trying to dial in ratios. Without the added wrap the idler allows, you are limited to a very small number of teeth on the small sprocket when running next to a large one and I don't think the 15mm would hold up long if pushed hard. Fine for a while if you baby it.

Scooter Parts had some decent options for a while but they all seem to be unavailable now. They still list them on their web site but if you try to buy they come up as "not available".

I've been doing CAD models for 3D printing for about 3 years. I can design any kind of pulley that there is a need for. I agree that there are really no good choices currently out there. I intend to fix that.

The pulleys that are available have the wrong width, or the wrong tooth count, or the wrong center bore/thread. They are all screwed up one way or another. My first two big sprockets are meant to be direct solutions for the GNG. I'll be making a 95T without freewheel and a 120T with. Both will be 20 mm wide and compatible with the 18T driver I developed. There will be more choices to come.

 

[LightningRods]

I think it is probably that the gear ratio is variable with the gen 1, and that there is a consensus that the gen2 will strip its planets very quickly with more power. I really like the gen2 for its robust sealed nature and simplicity, adding your 219 sprocket is just icing on the cake for that kit if the stock system fits your needs. I would really like to know the sound difference between it and a cyclone, as the cyclones are obnoxiously loud which would be a deal killer for most people I am sure, and also a destruction test of exactly what power it could take reasonably before it eats itself. Even a back to back test between it and a gen1 would be handy info. Personally I think it has been ignored too early as I have yet to read anyone breaking one....but I could be wrong.

I have a Gen 2 in my shop right now but it's a build for a customer so I can't really put 72V to it and see if it blows. I agree that it deserves more attention, even if only as the 'light' version of it's big brother. I recommended it over the Gen 1 for a female customer wanting a hassle free 800 watt commuter.

A cover, however light weight, for the belt/chain 1st reduction on the gen1 would really top it off, and probably fairly necessary for those of us who ride off road with the new epoxy sprockets as I dont think it would take much in the way of debris in between the belt and sprocket to ruin your day.

If I'm going to offer anything like a complete kit to people I'm going to have to cover the drives. I actually woke last night having nightmares about liability attorneys coming after me. If someone can get their bare toe into the drive somehow, it must be the fault of the negligent bastard that built it. :lol:
And yes you're right, mud and crud is not the belt's friend.

there has always been choices on the belt side......
http://www.electricscooterparts.com/beltcogs.html
but you were limited by the motor output shaft. With the correct belt tension you wont need an idler on the first stage with a 20mm wide belt. Actually even just the new addon pulley for the motor output shaft from lightning rods, and the 120t freewheeling pulley from electric scooter parts and 15mm wide belt might be enough for those running stockish power levels without an idler. But for overhead shock loading you would be far better off with a 20mm wide kit.

The Scooter Parts pulleys got you close (when you could get them) but they still weren't exactly right. The sole point of the idler is to bring the belt spread in to engage more teeth on the driver. The pulleys are just too close together for these tooth counts. I'm going to try running without an idler because I don't like them, but we'll have to see. At 48V I'm thinking that the 20mm GT2 belt is going to make up for that odd missing tooth of engagement.

 

[speedmd]

If your using a newer solid works, you can put in the material data and see what the belts safety factor is on the small tooth engagement on the small pulley. Gates may do this for you. I don't see it working with a rubber belt for long if your putting some power to it. A nice solid mounted double 608 bearing idler will most likely be a good bullet proof option, just to add some wrap.

cheers

 

[LightningRods]

If your using a newer solid works, you can put in the material data and see what the belts safety factor is on the small tooth engagement on the small pulley. Gates may do this for you. I don't see it working with a rubber belt for long if your putting some power to it. A nice solid mounted double 608 bearing idler will most likely be a good bullet proof option, just to add some wrap.

There are belt/pulley configuring apps out there on some of the suppliers web sites. I have everything in spec now except that the 120T is not far enough away from the 18T driver to close the belt angle and engage the ideal number of teeth. At 48V I'm thinking I'll get away with it because I am overkill on width with a GT2 profile. For higher voltages I tend to agree with you. I think a quality roller bearing idler is going to be needed to pick up another tooth or two of engagement. The smaller 95T is in spec and should be fine without an idler. Bottom line I'm going to have to run them to know for sure.

 

[ferret]

Hi,
I'm in the process of planning out a build that will be based on the GNG gen 1 motor and a custom reduction.
After lurking around and reading (most of) this thread, I am ready to ask the experts a some questions:

Christerljung and speedmd, you mentioned that taking the motor apart and reassembling it (to modify the shaft) is complicated, I would appreciate some more detailed info, as I am planning to do this and don't want do damage anything in the process.

And a question for LightningRods Mike, you recently wrote that you have sourced motors directly from the manufacturer and that you will have them available either stock or with a modified shaft, is that happening in the near future or only in the long run?

Avner.

 

[justlooking]

just a thought, but if the belt sprockets are to close together, couldnt another be used to link the 2 together ? so there will be 3 in line ??
there is a brown reverse wire on the motor , i take it that it will reverse the rotation that the motor will turn ??

i may be looking at this the wrong way ,,, but its just a thought

 

[LightningRods]

Hi,
I'm in the process of planning out a build that will be based on the GNG gen 1 motor and a custom reduction.
After lurking around and reading (most of) this thread, I am ready to ask the experts a some questions:

Christerljung and speedmd, you mentioned that taking the motor apart and reassembling it (to modify the shaft) is complicated, I would appreciate some more detailed info, as I am planning to do this and don't want do damage anything in the process.

And a question for LightningRods Mike, you recently wrote that you have sourced motors directly from the manufacturer and that you will have them available either stock or with a modified shaft, is that happening in the near future or only in the long run?

Avner.

Christer was the first one brave enough to crack the 'GNG' motor and dissect it's innards. Based on his lead I've taken several apart. The only really difficult thing is the amount of force that is needed to drive the motor spindle out of the armature and case bearings. Once you have the right side (non drive) case off you can see what is necessary. Use a rawhide or plastic mallet and just keep firmly striking the spindle. It will drive out. The motor side cases have a bit of sealer holding them in place but a chisel or blade screwdriver will tap them loose. Take them straight off, not cocked, because there are bearing press fit into the cases on the inside.

The center magnetic armature is a different challenge. The magnets are STRONG. I tied a strong cord around the armature and tied the other to a support post in my shop and pulled the case off of the armature. It takes some muscle to get it out. But that's it.

I do have a connection for the motors. They want a minimum order of 20 units. The cash investment has been stopping me. If I get enough interest I'll float the purchase and get them into the States. I will have to eventually to do my own mid drives. My machinist buddy will be moving to my town in about two weeks and then we'll get serious.

 

[LightningRods]

just a thought, but if the belt sprockets are to close together, couldnt another be used to link the 2 together ? so there will be 3 in line ??
there is a brown reverse wire on the motor , i take it that it will reverse the rotation that the motor will turn ??

i may be looking at this the wrong way ,,, but its just a thought

Triple reductions are common on RC mid drives where the motor is turning 10,000 rpm or more. With three pulleys it all gets so much easier. Three 3.5:1 reductions will give an overall reduction of about 43:1. I'm still thinking about it for my scratch built mid drive. I'm using an Infineon C7240-NC controller in my build and it definitely has a reverse feature. I also looked at the 'GNG' motor in China that has a cooling fan on the right side. They do that by having a long spindle that exits the case on both sides. The only thing that concerns me about using the cooling fan end of the spindle as a drive shaft is that the bearing on that side is a lot smaller than the drive side.

 

[Gab]

Lightning rods

"Three 3.5:1 reductions will give an overall reduction of about 43:1. I'm still thinking about it for my scratch built mid drive."

The problem with 3 stage is the drag and inefficiency. Yes it's easy to use 3 stages and get a high reduction, but this comes at the expense of space for all the stages and also more importantly their is a multiplying effect of the friction losses in the chain/belt and bearings with every stage . Also with every stage their is more drive train slack and loss of instant response. In a 3 stage their is 6 bearings and 3 chains or belt so their is a lot of losses.

Hence to get a high reduction without multiple stages you need to use a planetary gearbox. But these can be expensive, probably one of the cheapest and most compact and efficient planetary gearboxes in that regard are the common cyclone type planetary gearboxes and some people run them in an oil bath for even more efficiency. They are single stage and only use 1 chain so a lot less losses then a 3 stage chain setup. I have never heard of anyone break teeth on one of these on the sphere and they are a single stage and get 9.8:1 reduction and they use straight cut gears, which are more efficient then helical cut gears.

Gab

 

[speedmd]

You don't need three stages. If you are running a 10000 rpm motor and want to match pedal speeds possibly, but you still can go a double reduction then straight to the wheel. Chain is very efficient and hard to better. Gears are good but straight cuts are very noisy when made of metal, but do wear out and at times lunch them selves with major ramifications. LR is trying to maintain the belt reduction on the high revving side to quiet things down a bit and still eliminate the idler. With a idler the small next to large pulley is a non issue.

GNG motor only needs a single stage reduction to a jack and then you could go straight to the rear wheel as many have done with good success. With something like a three speed gear selection at the jack you could then bypass the crank entirely and have a good speed range for this great little motor. You would be shifting two places, but not have to reduce rpm and then increase them through the pedal system.