skyungjae
10 kW
How much more power will the 25mm belt be able to hold? I saw in a post a while back that the 20mm would hold 260% more, but those belts were difficult to source.
GNG, 1000W 48V BB-drive, $400
- Thread starter spinningmagnets
- Start date
gknowes
10 mW
hi lihtingRods have you been to smooth-on. com they have videos that can help you. like due not mix resin with wooden stir sticks 
LightningRods
1 MW
ferret said:
I did that in the wrong direction. I read that the mix ratio was 1:1 so I mixed it that way. Except that was by volume and I was using a gram scale to measure parts A and B. By weight you were supposed to mix 1:1.2 . Mixed with too much catalyst it was going off in about 2 minutes. The proportions on two part resin really matter! Don't 'eyeball' the mixture!
This fast curing resin is the strongest, hardest and most heat resistant material that this company makes. The long curing stuff was worthless. Flexible like rubber and turned to goo at about 120 degrees.
Denisesewa
100 W
Most all resins I've used require staying within 5% of specified ratios , some special circumstances require mixing at one extreme ( of that 5%) or the other to achieve certian properties such as elasticity or hardness. I have also post cured at 160 degrees to acheive max hardness without brittleness , however all this means nothing since each type (and manufacturer) has specific properties for their intended purpose.
I'm sure you've done your homework , the proof will be in end product which with your tenacity for success will work out just fine
I'm sure you've done your homework , the proof will be in end product which with your tenacity for success will work out just fine
Back to the discussion about belts on Oct 14, I too am in hilly SF, and have put about 200 miles on my bike so far. It started howling like a banshee again. The original belt doesn't look so bad, but I swapped it out anyway for a Goodyear belt, and thankfully it sounds much better. Working on a box for the battery and controller. Will post pics when it's done Right now the bike looks like a Jr. High science experiment.
Right now the bike looks like a Jr. High science experiment.
LightningRods
1 MW
My 3D printing service bureau just called. The prototype for the 90 tooth GT2 pulley is finished and shipping tonight! I will check all of the dimensions and then pull a casting mold. I should be making production pulleys by Thursday or Friday. Stay tuned!
I will check all of the dimensions and then pull a casting mold. I should be making production pulleys by Thursday or Friday. Stay tuned!
bee
100 W
With high power that BMX chain stretches quickly, pay attention to tensile strength when shopping for BMX chain for this kit, you can see some KMC specs at http://kmcchain.us/wp-content/uploads/2013/06/ChainGuide-BMX-Series.pdf
The connex 1g8 is the fattest BMX chain I could find, but I can't find it at a reasonable price anywhere: http://www.connexchain.com/Bicycle-chains/BMX/1_342.html
There is also this gusset tank chain: http://wallerbmx.co.uk/products/gusset-tank-chain/
Seems like 1500kg is around the limit for BMX chains, probably the limit of the pins.
The connex 1g8 is the fattest BMX chain I could find, but I can't find it at a reasonable price anywhere: http://www.connexchain.com/Bicycle-chains/BMX/1_342.html
There is also this gusset tank chain: http://wallerbmx.co.uk/products/gusset-tank-chain/
Seems like 1500kg is around the limit for BMX chains, probably the limit of the pins.
skyungjae
10 kW
LightningRods said:My 3D printing service bureau just called. The prototype for the 90 tooth GT2 pulley is finished and shipping tonight!
Times like this make me wish I had a GNG 1.1. :x
LightningRods
1 MW
The 25mm GT2 belt fits perfectly and the ACS Crossfire freewheel fits perfectly. It looks like we have a light bulb. 
The only thing that stands in the way of being able to bolt this pulley right up to any GNG Gen 1.0, 1.1, or 60v chain drive is the thread on the steel 1.375" freewheel thread to 12mm bore adapter that comes with the GNG. The one I have will thread onto cheap 4 bolt Chinese freewheels but not a quality 5 bolt like ACS or White Ind. It's been suggested than mine is a fluke because of GNG's 'quality control' and that may be. I am going to make both 3.07" flange to 12mm bore adapters for people who do not want a freewheel in this location, and a replacement 1.375" to 12mm bore adapter that fits quality freewheels. At the point where I am making my own stand alone mid drive kits I will not have access to the freewheel adapter that comes with the GNG anyway.
I'm making a mold of this prototype pulley today and will be casting production pulleys tomorrow. Barring the unforeseeable I should be shipping production pulleys by Thursday. FINALLY!
The only thing that stands in the way of being able to bolt this pulley right up to any GNG Gen 1.0, 1.1, or 60v chain drive is the thread on the steel 1.375" freewheel thread to 12mm bore adapter that comes with the GNG. The one I have will thread onto cheap 4 bolt Chinese freewheels but not a quality 5 bolt like ACS or White Ind. It's been suggested than mine is a fluke because of GNG's 'quality control' and that may be. I am going to make both 3.07" flange to 12mm bore adapters for people who do not want a freewheel in this location, and a replacement 1.375" to 12mm bore adapter that fits quality freewheels. At the point where I am making my own stand alone mid drive kits I will not have access to the freewheel adapter that comes with the GNG anyway.
I'm making a mold of this prototype pulley today and will be casting production pulleys tomorrow. Barring the unforeseeable I should be shipping production pulleys by Thursday.
FINALLY!
LightningRods
1 MW
Some visual comparisons between the stock GNG pulley and my new GT2 pulley.
The diameter of the 90 tooth is not that much greater than the 80. It will fit any version of GNG fitted with adjustable sheets.
This is the main difference. 66% more width on a belt pattern with 2x the grip of the HTD that comes with the GNG.
The diameter of the 90 tooth is not that much greater than the 80. It will fit any version of GNG fitted with adjustable sheets.
This is the main difference. 66% more width on a belt pattern with 2x the grip of the HTD that comes with the GNG.
skyungjae
10 kW
It's so beautiful. I'm looking forward to the new sheets and sealed jackshaft housings.
spinningmagnets
100 TW
I want to point out that the freewheel should last a very long time in this location. The biggest reason for moving it to the primary (belt side) instead of the secondary (chain side), was to achieve much more reduction while using reasonably-sized pulleys that will still fit.
However, The stock GNG drive 12T freewheel is not only an item from the "affordable" parts catalog (not strong), it is also located on the lower-RPM / higher torque side. In LightningRods configuration, the freewheel is moved to the higher-RPM / lower torque side.
The Bikemotive flanged freewheel is larger than the stock 12T too, so each pawl and bearing ball is less loaded than what they would be on a smaller freewheel. The quality of the steel in the Bikemotive bearings and pawls is also much higher quality.
However, The stock GNG drive 12T freewheel is not only an item from the "affordable" parts catalog (not strong), it is also located on the lower-RPM / higher torque side. In LightningRods configuration, the freewheel is moved to the higher-RPM / lower torque side.
The Bikemotive flanged freewheel is larger than the stock 12T too, so each pawl and bearing ball is less loaded than what they would be on a smaller freewheel. The quality of the steel in the Bikemotive bearings and pawls is also much higher quality.
litespeed
100 kW
Great engineering is what I see here. Really looking forward to my kit!
Great looking work!
Tom
Great looking work!
Tom
Secret1511
100 W
I just broke a #25 chain on the primairy drive! So it can be done 
Whiplash
1 MW
- Joined
- May 10, 2010
- Messages
- 2,906
Hey LR, so to do a complete swap over to this setup from a stock GNG kit, what all do I need? My brother wants to up the amps on his kit to push around 2k watts from 12s lipo. I am sure this will handle it. Can I get a price and part numbers to order it all up? Do I need a different BB as well?
Thanks for saving me a bunch of reading!
Bryan..
Thanks for saving me a bunch of reading!
Bryan..
LightningRods
1 MW
Whiplash said:
Hey Bryan-
I've intentionally designed this first Lightning Rods kit so that you can replace as much or as little of the GNG as you want. The parts I see as being essential to making the GNG work at all are my adjustable upper sheets, the 18 tooth 25mm wide GT2 driver pulley, 25 mm GT2 drive belt, 90 tooth 25mm wide GT2 driven pulley, and my freewheel flange to 12mm adapter (going into production now). This will get your bike on the road and keep you from having to baby and replace the stock belt constantly.
The next step after the primary drive is the secondary. The little freewheel in the drive sprocket is another weak point. It's small, cheap, and is under heavy strain from being on the high torque secondary side. I figured out that moving the freewheel over to the primary driven sprocket makes it possible to both run a high quality full size freewheel and also to change the secondary drive to #219 kart chain for 66% more reduction than bicycle chain. This will get your pedaling cadence more in line with the speed of the motor so you can pedal along at higher voltages. Quality Japanese or German #219 chain is stronger than all but the very strongest 1/2" chains.
Unfortunately yes the GNG BB is also cheap junk. The long axle in the BB is made of butter soft steel and will bend if you load it at all. People have also had lots of trouble with the crank arms stripping out. The sprockets are also cheap stampings and often arrive bent as mine did. Junk and more junk.
Long story short the motor and the jackshaft are the only decent parts on the GNG. You can either start with a GNG and replace parts as they bend, break or annoy you, or just buy a motor off of Mister Tao and build it up with my parts from the get go. If my primary pulley set sells well I'm going to start buying the 'small block' motors by the pallet load straight from the manufacturer in China. Lyen makes great controllers and the Cyclone ISIS BB looks like the best deal for the moment. Through the efforts of the people on this Forum we've figured out solutions to all of the problems with the GNG.
I intend to make my own complete mid drive kits. This first one is compatible with the GNG to help people who purchased the kit and found it unusable. Future kits (already in the design phase) will be 'clean sheet' designs that have nothing to do with the GNG. My web site below will eventually show everything that's available and have e-commerce. For the time being PM me for information.
Thanks,
Mike
Hello,
I have a couple of quick questions about the GNG 48v BB-drive. Is the version/ generation 1.1 designated by specific design changes from the original? What I mean is what was revised to the 1.1 that wasn't part of the version 1? Please correct me if I am wrong but I thought the version one was belt drive, no mudguard, integral motor pulley? Version 1.1 was belt drive, with a mudguard, and removable motor pulley? and version 2 was a chain drive primary? Let me know what you guys know. Thanks!
I have a couple of quick questions about the GNG 48v BB-drive. Is the version/ generation 1.1 designated by specific design changes from the original? What I mean is what was revised to the 1.1 that wasn't part of the version 1? Please correct me if I am wrong but I thought the version one was belt drive, no mudguard, integral motor pulley? Version 1.1 was belt drive, with a mudguard, and removable motor pulley? and version 2 was a chain drive primary? Let me know what you guys know. Thanks!
LightningRods
1 MW
kVAR said:
The important change on Gen 1.1 was changing from an open jackshaft that had aluminum bearing blocks outside of the upper sheets to a closed bearing tube that enclosed the bearings between the upper sheets. GNG said this was for "waterproofing" which I suppose it does to some extent (water and crud can still get at the bearings from the exposed side at the end of the tube). The most important thing was that it made the jackshaft area a lot stronger. I believe that the motor pulley is still machined from the end of the motor spindle on the 1.1.
Gen 2 is a completely different kit with a smaller motor that has a planetary reduction. The 60v chain drive so far has been called "60v chain drive". I guess you could call it Gen 1.2.
2020freerider
1 mW
Things are coming along nicely Mike, Great work!
Special thanks go out to Spinning-magnets for all the additional tech talk that you provide.
Cheers,
Joe
Special thanks go out to Spinning-magnets for all the additional tech talk that you provide.
Cheers,
Joe
robobike
1 µW
Hey all, just recently joined but have been reading the posts for a few weeks.
It is because so much information is shared here that I purchased a GNG kit so thought to say thanks to all that share their experiences. I was not sure which way to go but this forum helped me decide on the GNG kit.
My kit arrived this week and the only thing I have done is replace the chain tensioner wheels with plastic wheels I had lying around, this helped keep the chain on the secondary side (alignment issues) and kill some of the noise from the first stage (metal on metal contact from bearings) , the first chain reduction is very noisy, the chain seems almost too wide for the sprocket and rattles, must be replaced.
So far the bike has just been tested with the back wheel off the ground, apart from some updates need to make up some battery packs and work out how to mount them on frame. Overall very happy with the kit.
It is because so much information is shared here that I purchased a GNG kit so thought to say thanks to all that share their experiences. I was not sure which way to go but this forum helped me decide on the GNG kit.
My kit arrived this week and the only thing I have done is replace the chain tensioner wheels with plastic wheels I had lying around, this helped keep the chain on the secondary side (alignment issues) and kill some of the noise from the first stage (metal on metal contact from bearings) , the first chain reduction is very noisy, the chain seems almost too wide for the sprocket and rattles, must be replaced.
So far the bike has just been tested with the back wheel off the ground, apart from some updates need to make up some battery packs and work out how to mount them on frame. Overall very happy with the kit.
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