Switched to a GNG style "big block" swingarm coming soon!!

Whiplash

Whiplash

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May 10, 2010
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Here is my first sketch of what I want to try, the MAC is converted to mid drive style so the body of the hub does not spin but it bolted into the chassis using the cover bolts to both mount the motor and to increase rigidity of the frame. This will allow the frame yo be nice and narrow as it will be only as wide as the motor. This is nice for riding in the rough stuff but necessitates putting the batteries all in line so hopefully it will allow at least 20AH of 12s but I think it will. Any input is very welcome!


2012-12-27_12-38-13_929.jpg



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The exciting part of this for me is that I can oil cool the motor and use the ALY frame as the heat sync! I think it will allow great power potential from the little MAC motor and also still be nice and quiet!
 
Hats off for having a crack at building a frame. It can be a very satisfying journey.

Have you considered what happens to the chain when the rear suspension compresses?

A very similar thread and comments here: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=43599
 
Yes it should slack or tighten a bit but if I get the chain the right length the derailleur should be able to handle it. There are many frames with this design... Hopefully it'll work! ;)
 
The motor does not require any more reduction, that's the beauty of the 12T MAC. The cranks will hopefully be on the main frame because it will greatly simplify construction. I know I'll get some chain growth/shrink during travel but I hope to minimize that with pivot placement...
 
Well, I was limited on funds so I shopped around a LOT and found the best deal to be this one

http://www.everlastgenerators.com/PowerTig-185-Micro-3910-pd.html


It is IGBT switched and uses Siemens modules so for its price it seems quite good. I got it shipped to my door for $800 and considering it fared as good or better than the Miller Diversion of $1500+ in an independent test I saw I figured it should be pretty good! Its nice too since its an inverter type its quite small for its power too! Its about 1/4 the size of my old Miller Syncrowave 250DX water cooled unit I had to sell a few years back....
 
https://www.youtube.com/watch?v=fguSYx-gjjg&feature=youtube_gdata_player
 
Thanks for the rundown. I was looking a year and a half ago which is an eternity in today's market. About to start looking again and glad to steal a little of your research. Thanks!
 
Whiplash said:
Well, I was limited on funds so I shopped around a LOT and found the best deal to be this one

http://www.everlastgenerators.com/PowerTig-185-Micro-3910-pd.html

It is IGBT switched and uses Siemens modules so for its price it seems quite good. I got it shipped to my door for $800 and considering it fared as good or better than the Miller Diversion of $1500+ in an independent test I saw I figured it should be pretty good! Its nice too since its an inverter type its quite small for its power too! Its about 1/4 the size of my old Miller Syncrowave 250DX water cooled unit I had to sell a few years back....
Click to expand...

I heard about this online when looking into welding. Please follow up with how it goes with this welder.
And good luck with your frame!
 
Sure thing! It has a 5 year warranty so it should be pretty good, we'll see....
 
nice design whiplash! Nice to see how my idea gets children :) how fast will it go, i mean, why dont you want to drive the pedals through the MAC shaft, getting rid of the freewheel crank and some front sprocket diameter (=more ground clearance for free)?

Edit: I added a link to this thread to the collection post in the "hub motor conversion thread" http://endless-sphere.com/forums/viewtopic.php?f=28&t=45245&p=659473#p659473

Will it be 2-link or 4-link suspension? If you do 2-link (like I guess from the drawing) I propose to align the pivot point and to the chain line to gain a more driveable suspension feedback.
 
How fast do you want top speed to be @ what pedal cadence?
I'm being serious here. This is not a joke!

bØb
 
Well, I would like to get close to 40mph if I can. 38ish would be fine in high gear but with a low gear top speed of about 10mph Max so it will still climb a wall like it does now. Cadence at top speed is not too much of a concern but I would like to keep it under 100 at cruising speeds like maybe 28-30 just so the rider can add their 100 or so watts of power just for the sake of range.. I realize I will either need a custom rear cluster or two speeds on the motor to do this and the cluster seems easiest. I am not opposed to losing the freewheel cranks if I can find a simple, good looking way to do it. Since this will be my first frame from scratch, I need to keep it simple, I can always improve the design later...
 
OK I am leaning toward CrossBreak's idea with the motor driving the cluster directly and having a fixed crank on the left side to pedal through the motor. Please disregard the bad paint skills... Anybody feel like figuring out the gearing for me using a 6T MAC at 12S LiPo? I am looking to get close to 40MPH top speed and still have a granny gear for rock crawling below 10MPH. I MAY need two speeds on the motor drive side but I am not sure. It also looks like I will likely have to lower the motor a bit more in the frame so the swing arm can make its sweep without the chain hitting it...but the drawing would show the bike at its nominal height with the rider on board so it will sit higher in back when unloaded. I COULD put an idler on the arm pivot for the chain to hit when it compresses as well as a last resort but I hope to avoid things like that..
 

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  • Mid drive minus freewheel cranks...JPG
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OK Played around with the gears, it looks like a 12-36 casette should be ideal for me with a 12T front cog on the motor. This gives me a 1:1 ratio for the tall gear, simulating the same thing the motor will see if it was in the wheel so it should handle it fine, and it will also get me the speed I want, Then if I shift into the low gear (36T) I will get a top speed of around 10-12 MPH so it should be very similar to my existing setup that works SOOO well! I am getting excited about this now! I think it will be truly the best of both worlds in one bike! Somebody double check me though since I am not the BEST at gear math...

Thanks!
 
Hi,

Drive configured like this?:
fortune-hanebrink_psWBC_58.jpg
 
Similar but with the pedal gear on the left side of the bike...
 
OK I think I am ready to at least start the motor conversion! Thanks to Crossbreak and Mr electric, I am convinced this is the way to go and will do so hopefully tomorrow or at the very least get started! Very exciting! The motor I have has a steel gear in it so its good for some real power! I'll document and record every step of the motor as well so anyone willing can try it! Thanks for the help guys! Oh and thanks BOB for the gear ratios!
 
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