Two speed gear box for e-cargo bicycles?

Miles,

"I can draw the sprockets but aren't there already ones available, commercially? Track cogs etc."

All of the cassette single speed cogs, that I know of, are for 3/32" chain...too thin, and most have tall, single speed tooth profile, which won't shift well...needs flat top profile...only available up to 22 tooth. Would be better off using regular cassette cogs.

From my copy of Frank Berto's THE DANCING CHAIN, the bible of bicycle drive history:

In the 1890's 1/4" 6 mm chain and sprockets were the standard...heroic efforts to make 2 sprocket derailleurs using these chains.
By the 1910's...3/16" 5 mm chains and sprockets had taken over...2 sprocket derailleurs were in use.
By the 1920's 1/8" 3 mm chains and sprockets with 2, 3, and 4 sprocket systems were in use. Today this is the standard for single speed bicycles. (These bikes had 4 1/2" 114 mm spacing)
In 1936, Brampton introduced the 3/32" chain. This permitted freewheels with 5 sprockets to be used. (120 mm frame spacing)
At this point, the law of diminishing returns set in.

http://www.cyclepublishing.com/cyclingbooks/dc.html
 
How about these? http://www.velodromeshop.net/index.php?p=product&id=2153 You'd need to truncate the teeth, as you said. Only up to 20t, too. Still, as something to experiment with....

I could draw up the cogs, if someone wants to try this. The dimensions on the models I posted are accurate and I seem to remember collecting data on the fit of the Shimano type 9 spline.
 
Very nice info about chain development! Thanks guys!! :)

G.
 
"The Dancing Chain" is my favorite bike book.. :)

This is good, too: https://books.google.co.uk/books?id=a4IUAwAAQBAJ&printsec=frontcover&dq=hadland+lessing&hl=en&sa=X&redir_esc=y#v=onepage&q=hadland%20lessing&f=false
 
Miles said:
"The Dancing Chain" is my favorite bike book.. :)

This is good, too: https://books.google.co.uk/books?id=a4IUAwAAQBAJ&printsec=frontcover&dq=hadland+lessing&hl=en&sa=X&redir_esc=y#v=onepage&q=hadland%20lessing&f=false
Click to expand...

Just glanced at it, thanks! Very nice book... can't believe they used to "ice skate" to market back in the XVIII century... crazy!

G.
 
Warren said:
It would be much cheaper to double up cheap Sunrace cassette cogs. A quick, easy experiment. And it would tell us if 3.6 mm width would hang up in the chain on shifting.
Click to expand...

It's a worthwhile experiment, but keep in mind that so-called 1/8" (3.2mm) sprockets, for BMX and track bikes, actually measure about 0.100" (2.5mm) thick. The chains do have enough internal clearance for a 0.125" sprocket, but my impression is that using one makes them sensitive to alignment variation and inclined to stick or malfunction.

The same principle applies to so-called 3/32" sprockets, which are nominally 0.094 thick but measure about 0.080" thick if you examine them.

If you do your experiment, it would be worthwhile to try half-link chain, which costs more than the normal kind but has more space inside.
k77a.jpg
 
Miles said:
Just measured a Surly 3/32" single sprocket - it's 2.05mm thick.
Click to expand...

That's 0.081" for the metric impaired.
 
Just messing around with the idea of a 2 speed setup and came up with this idea. Sometimes the obvious can be easily overlooked so do any of you see why this wouldn't work? Seems to eliminate one chain compared to the familiar thud style 2speed.

motor rotation is ccw
1st gear red (input sprocket) is on a freewheel (green).
2nd gear red (input sprocket) is free floating on shaft via standard bearing but has drive dogs in hub.
Grey drive dog couples 2nd gear input sprocket to shaft.
Yellow sprockets are locked to shafts at all times.
purple is output to wheel (large purple sprocket)

So shifting is done simply by sliding the grey dog coupler into the 2nd gear input. No neutral position. Also regen is possible in 2nd gear only. I'm thinking it can't roll backwards with 2nd gear engaged. Anybody see any issues with the design other than maybe needing some idlers to improve chain wrap?

 
Miles said:
Lots of info in this thread: https://endless-sphere.com/forums/viewtopic.php?f=28&t=8644
Click to expand...


I found this https://endless-sphere.com/forums/download/file.php?id=19021 3d animation?? but my computer says it cannot open the file because it is damaged. Is there a way to re-post it here so that it works with out having to down load it? so far it looks the best. but I need to see how it works to understand how or where the ratcheting freewheels or one-way bearings, are.

so why doesn't some one manufacture a two speed gear box. there is definitely a market for them.
 
Hugh-Jassman said:
so why doesn't some one manufacture a two speed gear box. there is definitely a market for them.
Click to expand...
I have a design for a retro direct gearbox using a single planetary gearset. I finished the design work three years ago and made a prototype (it's not this one). That's as far as I've got. I wasn't convinced there was a market. My priority at the moment is electric motors....
 
So, why doesn't someone manufacture a two-speed gear box. There is definitely a market for them
Click to expand...

After many years of meeting electric bicycle big shots and pondering this very question, I have finally come to a conclusion on how to guarantee making a small fortune in the electric bicycle world...start with a large fortune.
 
Is it time to unveil the latest 2-speed tranny design?

Been a long while since anyone has made a seriouse inquiry.....& of the 10 units built & delivered, the only guy who ever posted a build with one was Aussie Jester. (Heck he built two bikes with them) that & Etards road racer(which I built) is sitting in a shed somewhere in the desert.

The only guy on the waiting list is Danny Mayes.
 
spinningmagnets said:
So, why doesn't someone manufacture a two-speed gear box. There is definitely a market for them
Click to expand...

After many years of meeting electric bicycle big shots and pondering this very question, I have finally come to a conclusion on how to guarantee making a small fortune in the electric bicycle world...start with a large fortune.
Click to expand...

LMAO!!

So true!!

G.
 
Thud said:
Is it time to unveil the latest 2-speed tranny design?

Been a long while since anyone has made a seriouse inquiry.....& of the 10 units built & delivered, the only guy who ever posted a build with one was Aussie Jester. (Heck he built two bikes with them) that & Etards road racer(which I built) is sitting in a shed somewhere in the desert.

The only guy on the waiting list is Danny Mayes.
Click to expand...

Sure! bring it on. Have you considered building a 3-speed dog box? I imagine you could use two dogs, one on the front shaft between 1st and 2nd gear and one on the rear shaft between 2nd and 3rd. Shift cable movement would be easy. I would never buy it of course.. cause I'm always broke... :(

Soon as I find the right gearset.. I'll start my next 2-speed auto.. should be about 15lbs lighter than the last one :mrgreen:
 
JIC not mentioned by others

http://xiongdamotor.en.alibaba.com/custom_page_1/New_Double_speed_Motor.html

or better?

http://xiongdamotor.en.alibaba.com/product/1604877927-220560510/Double_Clutch_2_Speed_E_bike_Motor_with_Amazing_Torque_Electric_Bicycle_Motor_6_freewheel.html

a 2 gear/speed hub

seem to max out at 550w?, but such measures seem highly subjective

they seem well reviewed

i quite fancy the idea of a 2 motor bike anyhoo - 2 motors, 2 controllers & throttles, 1 battery. less overheating issues?

I may do similar with my underpowered cargo bike- add 2 speed front hub motor. Mine is a 24" wheel, so I figure a motor geared for 26" should be about right for my cargo bike.

using the hub motor to get rolling would remove much stress for the chain

it may be that your biggest issue is uphill speed, so if one of the motors is free-wheeling and geared low, that second motor may only be needed for low gear work anyhoo.
 
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