donob08

Geo

About Odyssey, most of them are "Metric" freewheels for the small side of a flip flop hub (for BMX bikes). It may not fit on the bike your talking about. The catalogs do say right and left handed but they seem to still be saying Metric. I didn't know there were left handed Metric hubs.

The thing is, they need the small hub so that 13 teeth's worth of circumference fit around it.

Maybe they found a way.

Don

GeoKrpan

Hi Don,

It's late. I went out tonight and I'm too stimulated to sleep.
I have got to use a 13t freewheel so bottom bracket cups are out.
13t freewheels only fit metric hubs which are 30mm in diameter as opposed to 1 3/8".

I have been searching around on the internet.
I found a freewheel adapter for a 15mm shaft and bushings with a 10mm ID and a 15mm OD.
https://www.choppersus.com/store/prod...wheel-Adapter/
https://www.reidsupply.com/Detail.aspx?itm=DM-10012
That doesn't solve the problem because the freewheel adapter is 1 3/8".
1 3/8" is approximately 35mm. I wonder if that freewheel adapter could be machined down and re-threaded to work with the metric freewheel???

I have found all kinds of crazy stuff on the Internet.
An article entitled "How NOT to make a freewheel adapter"
https://kineticists.org/Community/tab...s/Default.aspx

A guy who made a freewheel adapter from something called a shaft coupler.
https://www.flickr.com/photos/38575446@N06/3804186687/

What I need is basically a cylindrical piece of steel with a 10mm hole down the center with
the outside machined and threaded for a metric freewheel.
Looked at that way it doesn't seem so formidable.

I have seen blog posts from guys who either made or had someone make them custom machined parts for their electric bikes, potential resources.

It's 2:30 AM in California, time to try and get some sleep.
Cheers,
George

donob08

Geo

I hope you got some sleep.

A thought that I keep forgetting to share:

Some time ago you wrote about under volting a 36V Unite motor.
That's a really good thought.

A DC motor's speed can be described by the equation:

Speed (in rpm) = K * Voltage where K is a constant for a given motor design: mass of magnetic material, windings in armature, etc.

So for the 36 volt motor

550 rpm = K * 36

rearranging that K = 550 / 36 = 15.28

So, at 24 volts RPM = 15.28 * 24 = 367

Now at design voltage the gear reduction has to be 550 / 60 = 9.17 for cadence of 60.
At 24 volts gear reduction = 367 / 60 = 6.12

With the lower reduction needed you might be able to use the available 16T freewheels. This gains more than going to 13T. 13 / 16 = 81% ratio of new reduction to old. 6.12 / 9.17 = 67% ratio of new reduction to old.

Don

GeoKrpan

Hi Don,

Got to sleep around 3 AM and I'm groggy today.
So you think under volting WOULD work.
So, do you think you'd use a 24v or 36v controller?

ElectricScooterParts shows a 36v 450w motor that looks like the Currie motor.
If it made 2/3rds of the power at 24v that would be 300w, if there is a linear relationship between voltage and power.
And, I might be able to use a BB cup after all with a 16t freewheel.
I'm having trouble envisioning how the BB cup would attach to the motor shaft.
In my mind the spindle hole is larger than 10mm but that might be an incorrect perception.
Would you run it by me your idea about how to mount it to the motor shaft?
You probably already have but somehow it's not sinking in.

Did you read the article "How NOT to make a freewheel adapter"?
It said welding does not work because the heat affects the temper of the metal.
It said machining is the way to go.

Having a freewheel adapter made from scratch has it's advantages.
It would be very strong and it could be made so that it utilizes the D-shape of the motor shaft.
Other people might be interested buying one too.

Ohhhh, time to take a nap.
George

donob08

Hi George

Hope you caught up on your sleep, party animal.

My idea for hooking the freewheel to the motor is pretty simple but I think is sufficient. I'd use a washer with a D shape 9mm center hole and have a machine shop mate it concentrically with the BB cup by lining them up and drilling two holes through them both while aligned and then putting pins through the two holes.

The motor nut will hold them together. The D washer is pushed against the step on the shaft where the flat ends. The pins hold things in alignment and supply whatever torque transmission the tightness of the nut and friction can't supply.

You probably have to have the "washer" fabricated. But it is a cheap part.

Don

GeoKrpan

Hi Don,

I emailed a guy who posts on Endless Sphere. He builds electric bikes AND CNCs his own parts.
I asked him if he would be interested in fabricating a freewheel adapter for me.
Haven't heard back yet.

I thought the gear on the motor was a D-bore but the replacement part that Currie shows on it's website uses keyways.
Here's a link.
https://www.ezipusa.com/103-ezip-motor-gear.html

I also posted a thread on V is for Voltage and Endless Sphere entitled "Running a 36v motor on 24v".
I thought I would get a quick answer but there have been no replies.

Your method of adapting a BB cup sounds good, makes sense, is easy for me to envision.

I will see what the inquiries net me.

Feeling better today, got lots of sleep last night,
George

GeoKrpan

I got one reply to my thread on Endless Sphere that said running a 36v motor on 24v should work just fine.

donob08

George

I think that "key" is just a cost reduction. After you put a round hole in the gear, you take a rectangular bite out of it, making a notch. Now you put in a rectangular cross section key in that fits into the notch and rests on the flat of the D. It's not like a soft, narrow key that's meant to shear if the load is too high. Either way, the "washer" can duplicate it.

Don

GeoKrpan

Hi Don,

Is the motor shaft D-shaped?

Another possibility is using the gear that comes with the motor as the "washer".
Pin the the BB cup to it.

Check this out.
https://www.emachineshop.com/index.ph...FRYiagod0lEmKg
Do you know how to use CAD software?
They say "Use our free easy to use CAD software".
I could give it a stab.

I've been reading a thread on Endless Sphere entitled "A different e-Zip Trailz".
They author complains about the noise the reduction gears make. He takes the motor apart periodically to grease them but the grease never lasts very long.
Then he gets a Ping 36v 10a LiFePO4 battery, he's overvolting.
Then he fries the motor.
That's as far as I've read.

Cheers,
George

donob08

Geo

I can't see, to say for sure that the shaft is D shaped. But Unite, the manufacturer says it is. I don't think it matters until you take one apart and sketch the washer. If there really is a keyway, the washer could do that.

Using the gear would be a problem I think. It is 7 mm thick. It, or the washer, would have to go on the shaft first so the cup is trapped between two fixed surfaces washer/gear and nut. The gear would move the chain 7mm farther from the gear case.

I do some CAD. But I don't think the washer needs more than a pencil sketch.

Don

GeoKrpan

Hi Don,

I'll probably go the washer route but I will continue to pursue the custom made freewheel adapter.
I got a reply from the guy who CNCs his own stuff and he said it wasn't worth his time to do one offs.
I replied that there are thousands of Currie bikes/kits in use and that the number is growing.

Southern California is burning, literally, and it's hot as hell.
George

donob08

George

I think it's time to pay the piper. I got a comment from a close friend about your note suggesting that perhaps thousands of eZip owners would like to follow the plan we have worked together to outline.

I hope I've made it clear that I don't think this is presently a workable idea. I said, in one note, "I suggest that you don't make any irreversible changes to the kit, you may want to go back". I noted that several people on the endless-sphere site have tried ankle banging, always turning Bottom Bracket systems and given up on them. I mentioned that I had looked seriously at this idea a year ago and given up on it as a loss. I also said I didn't want to block your creativity because there may be a way around these issues. I still hope there's a path and that you find it. As my friend points out 1,329 people have read these post and may think "there's a couple of intelligent guys with an idea worth looking at".

It is an idea worth looking at.

But from a good idea to a working doodad is a long ways. My whole "working" life was about developing ideas. I learned that it's not good to block ideas. Ideas should be tried, and soon. If they don't work they may lead to a different, better idea.

Last year I went from the idea to trying it in a pretty short time and said "well that doesn't look promising" and went on. I'd suggest that you find some crude way to try the concept. It might be better not to worry about CNC parts but principles.

I'm not saying I'm all knowing, but my friend who cautioned me is the only person I know who is as smart and honest as my mother and she's the mother of my sons.

So, there's my thought for tonight. I'd be glad to keep kibutzing. We may get somewhere.

Don

GeoKrpan

Hi Don,

The thing that amazes me most about electric bike forums is how little the people know about bicycles and cycling. To offset the negativity that that may imply the level of intelligence and knowledge is vastly above that encountered on bicycle blogs.
I am not at all daunted by your comments. I am going to build that bike. There is no great sum of money involved and if it's a bust I will end up with a nice new bicycle and a complete unaltered Currie kit for sale.
I am not afraid of flailing crank arms. I won't be using the power in situations where the cranks could come close to their maximum potential rpm. On this bike pedaling is the primary source of power, the motor the secondary source of power, exactly the opposite of the wheel driven setup. Flailing may happen but it is simply a matter of releasing the throttle or hitting the brake lever, both intuitive actions in the operation of a motor vehicle.
I appreciate your honesty and sincerity, Don, and you can count on me not to BS you too.
We will see, that bike will be built, and very soon.
Excited as ever,
George

GeoKrpan

Don,

I just got a reply to my second inquiry about a freewheel adapter.
The response was affirmative.
This time I asked that he only do the 3D drawing and that I would take it to a machine shop to have it CNC'd.
He asked me to make a rough drawing with dimensions, scan it, and send it to him.
I'm going to go out and get a set of calipers. Harbor Freight nearby.
Do you have some calipers?
It would be great if you could get the EXACT dimensions of the motor shaft.
Length of motor shaft, diameter, length of flat, length of threaded section, etc.
If not, it won't be long before I have a motor.
I will buy a D-bore sprocket as soon as I know the diameter of the shaft.
Excited,
George

misslexi

Hard words from one who appears determined to re-invent the wheel, lol

GeoKrpan

My point was that those who are of the opinion that my idea is not worth looking at based upon the potential maximum cadence don't know that it is not unreasonable for a well experienced cyclist.

My idea may be a bust or it might be fantastic. I don't think it can be determined until it's tried.
And, no one has tried it yet.

Sincerely,
George

donob08

Geo

I'm still with you.

Maybe that should say "in spirit". My point is, I wasn't trying to turn you from your project. I was trying to be sure that others, who saw our discussions, had a balanced view.

I think you should know I and some of the others who have looked at this, call a 200 mile (unassisted, those other miles don't add to miles we can gloat about, they're just practical stuff) biking week LAZY.

That said, I'm working on some CAD drawings.

With luck, you'll see drawings tomorrow. Next week I go on another 500 mile, road bike trip, this time, through the hills of North Carolina. 500 miles in 7 or really 6.5 days, not too shaby, eh, for a 66 yr old? Not to play the male role too strongly, but I'm willing to meet for a real ride if we can make our schedules match.

I guess I'm supporting misslexi's point. We all believe we're special. Sometimes it's a good thing to find out, just how special.

Don

donob08

Geo

Here are some pictures of your adapter for a Metric sized Free wheel.

They are from:

https://www.oaktreevet.co.uk/Trike/trike.htm

quote from that web page:

The motor is a 250W geared motor from Unite Motor Co Ltd in China. www.unitemotor.com product code MY1018. The contact there is Zhongfeng Li, email sales@cn-dcmotor.com
I fabricated a drilled aluminium bracket which would fit on the modified boom tube giving some fore and aft movement to tension the chain. On the right side is the switch box and on the left side is the motor and controller. The motor comes with a 9T fixed wheel and I removed this and using a small brass interface piece made by one of my clients fitted a LHD 13T BMX freewheel from Odyssey www.odysseybmx.com sourced through my local BMX store Odd Ball Mall www.obmx.co.uk

end quote.

Notice he has the freewheel flipped around compared to the way I've been talking about so it has to be LHD and have Left Hand threads on his adapter. But it is tightening on. He could have flipped it th other way and had Right and Right.

By the way, the motor shaft measures almost 12 mm and does have a keyway not a D flat. Oh, I think you could use the present sprocket with a regular BB cup by turning the shoulder on the sprocket down to the diameter of the hole in the BB cup, sliding the cup over it, adding a washer after the cup, and tightening with the nut. The cup still has to be pinned to the sprocket.

Also
One other fact I discovered. When ElectricScooterParts said the speed was 550 for 450 Watts and 383 for 250 Watts they were being inconsistent. The 250 runs at 3150 rpm no load and 2750 is it rated speed. 2750 / 7.18 = 383 the output speed they listed (7.18 is the gear reduction).
On the 450 W the rpm is 4000 no load and 3000 rated speed. But ElectricScooterParts lists the rpm = 550 which is ~ 4000 /7.18 . The rated speed would be 3000 / 7.18 = 418 rpm.

Now when you take account of running the 36 V motor at 24 V giving 2/3 the speed, 2/3 * 418 = 278 rpm. So the reduction needed for cadence of 60 is 278 / 60 = 4.64. So with 13 teeth on the motor sprocket the chainwheel is 4.62 * 13 = 60 teeth.

The vet has a 54 T chain wheel so his cadence to match is 67, at rated speed. Also his vehicle weighs 60 Kilo = ~ 132 lbs and then add his weight and two 80 pound dogs, so his motor will always be loaded. He still has an ankle banger, but the pace is reasonable. I never said that you couldn't maintain a cadence of 100, but I do question whether it would seem better than just biking unassisted.






https://www.bikeforums.net/attachment...1&d=1251903409


https://www.bikeforums.net/attachment...1&d=1251903409

GeoKrpan

Hi Don,

Thanks for sticking by me in spite of my emotional outburst.
I should have waited until I could look at things more rationally.
The downside of passion.
Thanks for those two posts, I don't have time to respond to them right now.
Got to go see mom in the rest home and then a nighttime with a guy whose training for the Furnace Creek 508.
66 and still kicking ass, good for you.
One of my riding companions is 65 and climbed 1.5 million vertical feet in 2007 mostly on the dirt on a 29er singlespeed.
I'm a measly 56.
Cheers,
George

donob08

Geo

Your last message cleared things up a good bit.

You have said a couple of times things like:

"My idea may be a bust or it might be fantastic. I don't think it can be determined until it's tried.
And, no one has tried it yet."

I think I and others have thought 'I know six, three, two or whatever who have tried something nearly identical to what your proposing"

It might of been more effective to say ' no one crazy enough to consider being part of a Furnace Creek 508 effort has tried it before'. It's not your bike that will be different, it is your willingness to take physical abuse. More power to you, if that's what you like.

My sons have done some of the exterra race things, mountain bike, trail run and swim. I say 'more power to them, too'. I just hope their bodies are in working condition when they hit my age. I played sports in HS and college and can identify the game that caused that crick in my ....

So, I think that veterinarian in jolly old can answer any question you have. He might even lend you a few 'stone' of extra weight to slow the beast down until you get in synch with it. His machine must weigh 450 pounds when loaded. It does say the motor is a good one.

Did you notice he is not happy with the performance of his spokes? I can't image why. You'd think 3 bicycle wheels could hold 450 lbs, easy, just don't hit a bump.

Any how, continued good luck with your project.

Don

GeoKrpan

Hi Don,

Here's the logic for going with the 450w setup first.
That's what comes with the kit or bike, whichever I buy.
If it doesn't work I'll resort to the 250w motor or 36v motor on 24v.
Another thing, MY1080xx motors seem to out of stock with domestic retailers.
I searched for them on ebay and all of the sellers were in China.
I could be the residual effect of the one year exclusive rights that Currie has/had on these motors.
I wouldn't hesitate to buy a motor from China because they're only $50-60, not much at risk.

But, here's the best reason, curiosity.
If I didn't start with the 450w motor I would always be wondering what it was like.
I guess I would rather have a "hairy" setup that had the potential to get me into trouble rather than a tamer setup.

I was a surfer from age 12 to my late thirties. I took up road cycling when I no longer had the time to go to the beach. Next I moved into mountain biking. My latest passion is single speed cyclocross. I love it so much that I'm going to be building a drop bar mountain bike using the WTB Mountain Road handlebar.

Have you ever read the warning page on the Stokemonkey site?
Here's the link: https://cleverchimp.com/products/stokemonkey/warnings/

Unlike the Cyclone setup the Stokemonkey does not have a freewheeling device on the cranks.

I will now comment on your two earlier posts.
Cheers,
George

GeoKrpan

Hi Don,

That's good news about the rated speed of the 450w motor. That's only 35rpm faster than the 250w.
The vet in Old Blighty didn't breath a word about a cadence issue or about the durability of the Odyssey freewheel or freewheel adapter.
It's funny how the vet and I chose the same paths with no knowledge of each others doings.
Seeing the photo of his freewheel adapter makes me think that CNCing really isn't necessary.
It is merely a matter of finding a "gear blank" (Google it) of the approximate dimensions, making the hole and keyway, machining the outer diameter to 30mm, and then threading it.
More traditional machine shop stuff rather than CNC stuff.
I was thinking that some sort of provision was needed to hold the freewheel adapter while removing the freewheel but now I realize that it's not necessary. Good, that simplifies things.
The mindset of the crank driven setup is entirely different.
With the crank driven setup you would never allow the cadence to build to an unmanageable speed.
You'd shift up just as instinctively as you would do on an unassisted bike or a manual transmission automobile or motorcycle.
Another idea in common with the vet is the idea of no throttle but rather a power full on or off switch.

I had been wondering about how the power drops off when you let go of the throttle and the good vet answered that question, it takes a second for the power to drop off. No problem, for one second you'd be braking and pedaling at the same time.

Don, more and more, I'm thinking this is going to work. Are you getting that feeling?

Cheers,
George

donob08

Geo

Interesting thoughts. There is one thing though, the clever chimp uses a wheel motor. Now for a bike to go 22 mph = ~ 29 ft per second the say 24" (2 ft diameter ) wheel which has a circumference of about 6 ft. C = pi * D or 3.14 * 2 ~ 6 says the wheel is doing 5 revolutions per second or 300 rpm at 22 mph. I'm not sure what the motor is limited to in this application, probably lower than 22. The gear reduction for the monkey (motor to crank) looks like maybe 5 to 1. So the crank is doing 60 rpm. The my1018 is doing 418 rpm.

Don

GeoKrpan

Hi Don,

On the Stokemonkey ordering form page there are two choices of stokers cranks.
One is a mtb crank, the other a compact road crank, 44 and 50 tooth respectively.
I can't really tell from looking at the illustrations but I would bet that the freewheel on the motor is at
least 16 tooth. I plan to use a 53 tooth chainring and a 13 tooth freewheel.
50/16 = 3.125, 53/13 = 4.077
The 53/13 combo provides about 30% more reduction.
It would come close to offsetting the motor speed differences.

I can't find specifications for the Stokemonkey on the Internet.

Tonight I had dinner with a guy, Todd, whose brother worked for Currie on the first generation kit.
Todd calls himself an electric vehicle inventor and has built several vehicles.
I asked Todd to ask his brother for help with the machining of the freewheel adapter.
It's all a coincidence, Todd and I were friends before any of this electric bike stuff.
He sure enjoyed hearing about my plans.

It's late, talk to you tomorrow,
George

SeizeTech

First off, I wish you all the best, I really like what you are talking about.

But................

If you were to assign a $ figure to all the time that you've been wasting on this forum, it would have made sense to just go out and buy the parts and give it a try. You'd uncover this science alot faster through trial and error, imo.