Project Cove GNG-Spot build thread

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Project Cove GNG-Spot build thread

Post by ferret » Dec 27, 2013 1:19 pm

This build thread will document electrifying my Cove G-Spot FR bike using a GNG type motor.

The Cove frame was great fun going downhill but a pig pedaling uphill so I got a different bike for singletrack riding with my buddies. I still liked the bike so instead of letting it gather dust I decided to combine my MTB and electric RC hobbies and install a brushless/lipo system in it.

Cove G-Spot before starting the project, after fork and front brakes upgrade in preparation for electric power:
IMG_20131205_181840_755_30.jpg
I have been researching, planning, designing and gathering parts for the last few months and now actually starting the build.
I will post to this thread as I progress.

Avner.
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Planetry reduction

Post by ferret » Dec 27, 2013 2:10 pm

I wanted my reduction to have a high ratio so I could lower the motor RPM (using a 50V battery) to match my pedaling . I preferred to avoid using belt or chain reductions that might catch on my legs or require fabricating a cover and I wanted the reduction to be as compact as possible.

Inspired by the Dogati build I saw here on ES, I decided to use Matex planetary reduction gears. My setup consists of 2 stages, a 5:1 and a 4.8:1 giving a total reduction of 24:1.

Thumbs up for ES member Gerard (comradegerry) that helped me source the Matex gears.

The following photo show (left to right) the parts used for the reduction.
Motor-to-reduction adapter plate
Gears and spacers
End plate
IMG_20131227_203216_269_30.jpg
Test assembling the parts:
IMG_20131227_204721_227_30.jpg
IMG_20131227_204800_837_30.jpg
I plan to use some RTV silicone or gasket maker between the gears, spacers and plates so I could pour a little gearbox oil inside to keep things lubricated like a car's gearbox.
Last edited by ferret on Dec 28, 2013 3:22 pm, edited 1 time in total.
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Re: Project Cove GNG-Spot build thread

Post by comradegerry » Dec 27, 2013 3:57 pm

That is a great looking bike to start with, electrically assisted, it is going to be very sharp indeed.

Really looking forward to see it evolve; great fabrication skills on the mount, is that the work of a well programmed computer or a patient perfectionist with a drill press and a file?

Subscibed :D

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Re: Project Cove GNG-Spot build thread

Post by kfong » Dec 28, 2013 1:23 am

Nice, I have a pair of those 4.8:1 as well. Where did you get the mating shaft? If it was from Matex, What is the model number? Looking forward to the build. More detail on shaft connections and if you plan to use an inline freewheel, total width of final assembly. I'm also curious to the noise level and how well these planetary gears hold up in actual use.

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Re: Project Cove GNG-Spot build thread

Post by ferret » Dec 28, 2013 3:40 am

I drew up the parts in Solidworks CAD software and had them made at a local machine shop.
Most of the parts involve shapes and precise dimensions that I am unable to achieve in my shed.

The 5:1 gears' input is a splined shaft that plugs into the output of the 4.8:1 gears. I will use 2 freewheels (3 if you count the one built in to the standard rear hub) so I will be able to use pedal power, electric power, both or neither without too much drag.

Total designed width of the final assembly is 156.3mm, to be squeezed between the crank arms of a Shimano ZEE 83mm crankset. I had to literally agonize over every millimeter when designing it to make everything fit. That is also one of the reasons that parts had to be fabricated by a shop rather than made by me.

As for the noise level and how well these planetary gears hold up in actual use, I am curious myself and hoping no to encounter any nasty surprises down the line.

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Re: Project Cove GNG-Spot build thread

Post by whereswally606 » Dec 28, 2013 4:28 am

Hey ferret, I have those mates gears too. Was going to use a 80100 on them but dogati broke his putting too much power through them. Do you have the cad files for the rear of the matex transmission ? Have Subscribed gonna be an interesting 2014 build
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Re: Project Cove GNG-Spot build thread

Post by ferret » Dec 28, 2013 5:30 am

This build is planned for around 1 KW and according to my calculations the Matex gears should be able to handle 1.5 KW (about 30 amps) so hopefully they will be up to it. Do you know how much power broke them in the Dogati?

I downloaded CAD files from the Matex site:
http://products.matexgears.com/viewitem ... ?forward=1
Select the part you need files for and on its page find the link for 3D in the VIEW CAD DRAWING box on the upper right part of the page.
Last edited by ferret on Jan 25, 2014 5:33 am, edited 1 time in total.
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Re: Project Cove GNG-Spot build thread

Post by whereswally606 » Dec 28, 2013 5:55 am

That's a cool tip about the 3d on the matex website. The bit about the failing dogati transmission was early on his that massive thread. But he was doing way more than 1kw so you should be fine.
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Jackshaft

Post by ferret » Dec 28, 2013 3:20 pm

As I mentioned before, the jackshaft assembly includes 2 freewheels.
The inner freewheel and its sprocket will be connected to the rear wheel cassette by the main chain.
The outer freewheel and its sprocket will be connected to the chainring by a short chain.
This setup was inspired by the M55 bike and by builds I saw here on ES.

The parts used for the jackshaft assembly (top left to bottom right):
Jackshaft, inner bearing, inner freewheel adapter, inner freewheel, inner sprocket
spacer, outer freewheel adapter, support bearing, outer freewheel, outer sprocket
IMG_20131228_185032_721_50.jpg
After installing the inner bearing, the inner freewheel adapter is clamped to the jackshaft by 2 setscrew 90 degrees apart.
IMG_20131228_192653_948_30.jpg
The rest of the parts are then installed.
IMG_20131228_213428_153_30.jpg
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Re: Project Cove GNG-Spot build thread

Post by Rouckie » Dec 30, 2013 8:22 am

Hello,

I would like to use matex gears as well, dependent on the pricing. May I ask you how much they cost? I can machine the needed parts myself. Do you know of a supplier in europe?

thanks,

Roel

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Re: Project Cove GNG-Spot build thread

Post by ferret » Dec 30, 2013 9:22 am

Unfortunately I had problems locating a supplier myself. I got the Matex parts either secondhand or from an surplus shop on ebay.
Sorry I could not be more helpful.

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Re: Project Cove GNG-Spot build thread

Post by Miles » Dec 30, 2013 11:47 am

Matex units are quite expensive in small quantities, through their usual channels. The ex Currie USPD ones are relatively cheap though: http://www.ebay.com/itm/Currie-Planetar ... 4173d364b0 They're made by Matex.

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Re: Project Cove GNG-Spot build thread

Post by ferret » Jan 02, 2014 4:28 pm

The build continues:

Attaching the jackshaft to the reduction:
IMG_20140102_221953_561_30.jpg
The next parts to be assembled:
IMG_20140102_223408_655_30.jpg
Bolting them on:
IMG_20140102_224400_762_30.jpg
Test fitting the crank:
IMG_20140102_230359_411_30.jpg
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Re: Project Cove GNG-Spot build thread

Post by etard » Jan 02, 2014 5:14 pm

This is gonna be sweet! I miss my G-Spot :(
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Motor prep

Post by ferret » Jan 23, 2014 12:40 pm

After some delays, I'm back on the job.

Work on the stator was:
Replacing phase wires.
Rerouting the phase and sensor wires.
Installing a temperature sensor.
Epoxying winding.
Countersinking bolt holes.
Drilling radial hoes for backplate attachment.
IMG_20140110_221749_917_40.jpg
IMG_20140110_221849_733_m.jpg
After the stock motor shaft got somehow bent, I had a replacement one machined from 4340 steel. I got some NSK bearings to replace the stock ones.
IMG_20140120_192210_596_30.jpg
Installed the new bearings in the frontplate and the new (thinner) backplate.
IMG_20140121_203311_861_30.jpg
Finally all he parts were bolted together.
IMG_20140121_211027_560_30.jpg
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Test fitting

Post by ferret » Jan 23, 2014 12:58 pm

Left had BB plate, spacers and strap anchor:
IMG_20140113_212051_281_30.jpg
Bolting everything together.
IMG_20140121_215046_809_30.jpg
IMG_20140121_215325_978_30.jpg
Test install on the frame.
IMG_20140123_191117_848_30.jpg
IMG_20140123_191541_243_30.jpg
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Re: Project Cove GNG-Spot build thread

Post by kfong » Jan 23, 2014 1:09 pm

Cool project, I like the gear reduction and how compact you made it. How is the noise output? Vids?

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Re: Project Cove GNG-Spot build thread

Post by etard » Jan 24, 2014 10:25 am

This is really a nice build, I am very impressed so far. What are your plans for battery and enclosure?
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Re: Project Cove GNG-Spot build thread

Post by ferret » Jan 24, 2014 2:22 pm

For the build I bought 2*6s 8 Ah lipo packs. I hope that they (at 355 Watt hour) will give enough runtime.
I have some rough idea how to place them:
IMG_20140124_204655_305_33.jpg
I don't want to invest the time building an enclosure before I know for sure which batteries I'll be using.

I have a rough idea of 3d printing brackets that will attach to the top ant bottom tubes with aluminum sheets protecting the sides. I would prefer to retain the ability to mount the bike on a hatchback carrier.
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Re: Project Cove GNG-Spot build thread

Post by ferret » Jan 24, 2014 7:20 pm

Testing the motor:



The grinding noises are from the speed controller's fan.
Last edited by ferret on Jan 25, 2014 5:35 am, edited 1 time in total.
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Re: Project Cove GNG-Spot build thread

Post by Whiplash » Jan 24, 2014 8:57 pm

etard wrote:I miss my G-Spot :(


That's something I NEVER miss!! :twisted:
Power is a fascinating thing, the more you have, the more you want, but the real power is having the restraint not to use it all at once...............Um...Yeah..

The harder you work.....The luckier you get!!

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Re: Project Cove GNG-Spot build thread

Post by Whiplash » Jan 24, 2014 8:58 pm

Seriously though nice build!
Power is a fascinating thing, the more you have, the more you want, but the real power is having the restraint not to use it all at once...............Um...Yeah..

The harder you work.....The luckier you get!!

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Re: Project Cove GNG-Spot build thread

Post by Sean9002 » Jan 24, 2014 11:07 pm

etard wrote: I miss my G-Spot :(
Im sure some one will offer to help you find it :twisted:
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Re: Project Cove GNG-Spot build thread

Post by Whiplash » Jan 25, 2014 12:48 am

I just realized those are planetary gears! I KNEW somebody had to make those!! Were they expensive? Where did you get them?

Edit: Just saw your replies above..
Power is a fascinating thing, the more you have, the more you want, but the real power is having the restraint not to use it all at once...............Um...Yeah..

The harder you work.....The luckier you get!!

"People who say it can't be done are often interrupted by those that have already figured out how to do it!"

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Re: Project Cove GNG-Spot build thread

Post by Whiplash » Jan 25, 2014 1:25 am

Miles wrote:Matex units are quite expensive in small quantities, through their usual channels. The ex Currie USPD ones are relatively cheap though: http://www.ebay.com/itm/Currie-Planetar ... 4173d364b0 They're made by Matex.

Miles, what do you think max power handling for one of the Currie ones would be? To be honest it looks beefier than the Mac planetary! I have always wanted a planetary reduction instead of belts or chains. So much more elegant!
Power is a fascinating thing, the more you have, the more you want, but the real power is having the restraint not to use it all at once...............Um...Yeah..

The harder you work.....The luckier you get!!

"People who say it can't be done are often interrupted by those that have already figured out how to do it!"

Email me @ currentcycles@gmail.com
OR check out http://www.CurrentCycles.net

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