1st post--Mid Drive Project--

O

organicmechanic

10 µW
Joined
Sep 3, 2012
Messages
6
I have a idea for my mid drive bike build. I have a dual suspension, disk brake equipped DH bike to build on.

Here is what I am wanting to use in the build.

The freewheel crank set-
http://www.sjscycles.co.uk/shun-alloy-104-pcd-4-arm-freewheeling-cranks-170-mm-silver-prod23859/

The motor -- 36 volt 600 watt gear reduction motor with mounting bracket and 10 tooth #40 chain sprocket
http://www.monsterscooterparts.com/...bracket-10-tooth-40-chain-sprocket-1020z.html

Battery Pack--
http://www.goasisenergy.com/product...ith-4a-charger-and-battery-management-system/

I havent settled on a controller yet.

I am hoping that this is a good start.

My question is, will it move me and my 300+ lbs self down the road at a good clip? I am wanting a good 25+ mph on the flats and a decent range.

Have any of you all had any experience with the companies listed?

Is there anything that I should do differently? Any input is appreciated.
 
Some hills, mostly flat, plan on using as a pedal assist so I get some of the exercise out of it. As for the stops and starts, normal city stuff, will allways start off on the pedals and when get going, then kick it up.
 
I am sorta in the same boat as you. 300+ and crave 25mph+ and the pulling power to climb a grade. I was looking at you links and noticed your motor selection is not freewheel. Do you plan on turning the motor when peddling only?

The things I am looking at are GNG or Cyclone paired up with Nuvinci n360.

I currently use a Currie eZip Skyline 250w 24v and its way underpowered. But was a great starter. The only issues so far with it is it can't handle a grade without overheating. I have used it for 4 months and with me exceeding the weight limit I am seeing stress fractures. So I will have to find a new bike soon.

I would love to know what you end up going with and you experiences installing and using. It would be nice to know what works and doesn't. I have been reading all sorts of posts here and find them informative. The things that interest me about your post is the system requirements.
 
I am going with a set of Tandem cranks that have the freewheel in the set it self. I am going to be able to coast as the motor does the work. At least that is my hope.
 
organicmechanic said:
I am going with a set of Tandem cranks that have the freewheel in the set it self. I am going to be able to coast as the motor does the work. At least that is my hope.
Click to expand...

In that case, you will trash the crank-mounted freewheel in a hurry. Freewheels are not designed to overrun when there is chain tension on them; they have crappy little bearings. The GNG kit uses a support bearing to help mitigate the lateral deflection of the freewheel, but even that doesn't make the freewheel's bearing suitable for a job it was never designed to do.

Have a look at Stokemonkey, and get used to the idea of pedaling along with the motor (even if you aren't doing a lot of real work with them). Otherwise you're just setting yourself up for mechanical failures. If you're handy with machine tools and technically ambitious, you could build something for yourself using a sprag clutch or CSK one-way clutch bearing. Bike freewheels just aren't going to cut it.
 
Chalo said:
In that case, you will trash the crank-mounted freewheel in a hurry. Freewheels are not designed to overrun when there is chain tension on them; they have crappy little bearings. The GNG kit uses a support bearing to help mitigate the lateral deflection of the freewheel, but even that doesn't make the freewheel's bearing suitable for a job it was never designed to do.

Have a look at Stokemonkey, and get used to the idea of pedaling along with the motor (even if you aren't doing a lot of real work with them). Otherwise you're just setting yourself up for mechanical failures. If you're handy with machine tools and technically ambitious, you could build something for yourself using a sprag clutch or CSK one-way clutch bearing. Bike freewheels just aren't going to cut it.
Click to expand...

Chalo, do you have any actual experience with crank mounted freewheels? I ask because you seem to speak with conviction, but there are plenty of riders on this forum who have been using crank freewheels for quite a while with no large problems. They do wear out in time, but they are not expensive and should be just fine with a small 600 watt motor.
 
looking at the cranks its looks as though the freewheel cassette is replaceable. so It doesnt look as though it would be an issue if and when it does fail.
 
fizzit said:
Chalo, do you have any actual experience with crank mounted freewheels?
Click to expand...

Yes, I have replaced a few, mostly on tandems and trials bikes. The tandem ones disintegrate because they are overrun under load; the trials ones bust up because they are used at about 3X normal torque and kicked hard.

E-bike freewheel cranks are overrun under more than human power, and at about 3X normal torque when they are pedaled. The worst of both, in other words.

Single freewheels are pretty non-awesome overall, and they have a high failure rate even in normal use.
 
I have over 1200 miles on my White ENO freewheel cranks with ZERO problems running a MAC mid mounted through the gears with 1200 watts on tap and it also got used for a couple hundred miles with an RC motor also MID mounted running almost 2000 watts. I climb under heavy loads off road all the time as well. I would not hesitate to run the ENO at my power level and below. If you want more than 1200ish watts then I would try something else maybe but for your use at your power level it should last a long time...
 
Whiplash said:
I have over 1200 miles on my White ENO freewheel cranks with ZERO problems running a MAC mid mounted through the gears with 1200 watts on tap and it also got used for a couple hundred miles with an RC motor also MID mounted running almost 2000 watts.
Click to expand...

White Industries ENO freewheels are pretty exceptional, both in their mechanical design and construction, and in their purchase price. They certainly don't "only cost like $10", as a previous commenter said about single freewheels. If they have a serious engineering drawback, it's that they only have a single row bearing, and thus must be set up with good chainline to avoid off-axis forces. But that's best practice with any freewheel.
 
organicmechanic said:
I am going with a set of Tandem cranks that have the freewheel in the set it self. I am going to be able to coast as the motor does the work. At least that is my hope.
Click to expand...


Here's a freewheel crankset I put together recently. Yes thats a rear 9c hubmotor but soon to replaced with a mid drive of some sort.


I went with isis trial tech cranks cause they look cool, are stronger than square drive and measure 175mm instead of the common 170mm.
 

Attachments

  • P1010193.JPG
    P1010193.JPG
    99.5 KB · Views: 1,488
Used two ENOs in my e-bikes/trikes have also had zero problems with them
White Industries (makers of ENO freewheels) also do a freewheel made specifically
for use in the cranks, its sold exclusively by sickbikes.com...best of luck with the build

KiM
 
OK, here is what I am going with ---I think this will fit into a good budget build that is with in reason and alows for growth.

http://www.bikeberry.com/engine-kit-parts/accessories-1/motorized-bike-jackshaft-kit.html

that seems to have everything for the freewheel crank down to the jackshaft transmission. then I was looking at this other kit http://www.sickbikeparts.com/Manuals/Shifter kit.pdf

I lke the nice heavy duty upgrade option...

now to spin all this around I am going in this direction.

http://www.czbrushlessmotors.com/el...or-p-73:5dfe7250bba1e927e8f3e3fe04052424.html

now all this is only as good as your battery--

http://www.lifepo4.in/60v20ah-.html

I am going to be machining my own mounts and tensioners and welding (spoolgun or Tig) on to the frame it self.

I was over reading this great time killer at work http://www.electricbike.com/

Brakes are always a plus--http://www.amazon.com/AVID-ELIXIR-Hydraulic-Brakeset-Brake/dp/B009H93WDC/ref=pd_sim_sbs_sg_6

So I made a handshake deal with a buddy at work that if he puts all my parts on his credit cards I will title over my BMW...I will start posting pix as soon as I get out of lay-out.
 
You must log in or register to reply here.

Similar threads

Z
Help me choose a 48V battery for a TSDZ2 mid drive conversion
Replies
11
Views
262
Zambam
Z
K
Using a hub motor as a mid drive
Replies
6
Views
1,305
Bullfrog
B
A
Outrunner left side mid-drive conversion
Replies
19
Views
1,888
crazy dreamer
C
R
    • Like
A critique of mid-drive riding recommendations (and hub drive criticisms)
Replies
15
Views
5,586
Bullfrog
B
R
    • Like
Really good article comparing Bafang vs. Tongsheng vs. CYC
Replies
12
Views
11,670
999zip999
999zip999
Back
Top