Two speed gear box for e-cargo bicycles?

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gman1971
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Re: Two speed gear box for e-cargo bicycles?

Post by gman1971 » Feb 06, 2016 9:09 pm

Chalo wrote:I worked on an oddball old road bike the other day that had problems with the chain falling into the gap between front rings. Even after installing the narrowest possible spacers and truing up the rings, there was still enough space to cause trouble. So after assessing the six-speed freewheel and the derailleur for show stoppers, I put a 1/8" BMX chain on it. It worked surprisingly well. The only ill side effect was the increased need for front derailleur trimming to eliminate rub.

I can't say that it would be a good idea for 7-speed or more, though.
Maybe there is a way to retrofit the Shadow Plus derailleur with thicker sprockets and use it for a 5 or 6 speed with a thicker chain... would be interesting...
I am all about high-speed, low-drag, mid-drives and gears...
A-1B trike, 6+kW, 65+mph (Cyclone powered): https://www.youtube.com/watch?v=oFC8MRwvgUM
A-2A trike 3kW, 50mph (Cyclone powered): https://www.youtube.com/watch?v=bNoqp0wl6Vo
eB-1C bike 3kW, 42mph (Cyclone powered): https://www.youtube.com/watch?v=_weSmz_h3Ig

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Chalo
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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Feb 07, 2016 2:00 am

gman1971 wrote:Maybe there is a way to retrofit the Shadow Plus derailleur with thicker sprockets and use it for a 5 or 6 speed with a thicker chain... would be interesting...
Index 6-speed hearing has 5.5mm interval spacing. Old 6-speed thumbshifters have a "phantom" click (overshift of the last gear) that can serve as a 7th gear. My guess is that a stack of 7 sprockets at 6-speed spacing would fit nicely on an 8/9/10-speed cassette body, and could be compatible with 1/8" BMX chain. You'd just have to add spacers to the stack to achieve 5.5mm intervals.
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Re: Two speed gear box for e-cargo bicycles?

Post by gman1971 » Feb 07, 2016 2:35 am

Chalo wrote:
gman1971 wrote:Maybe there is a way to retrofit the Shadow Plus derailleur with thicker sprockets and use it for a 5 or 6 speed with a thicker chain... would be interesting...
Index 6-speed hearing has 5.5mm interval spacing. Old 6-speed thumbshifters have a "phantom" click (overshift of the last gear) that can serve as a 7th gear. My guess is that a stack of 7 sprockets at 6-speed spacing would fit nicely on an 8/9/10-speed cassette body, and could be compatible with 1/8" BMX chain. You'd just have to add spacers to the stack to achieve 5.5mm intervals.
This is something worth considering... and making the derailleur thicker is only a matter of putting washers around the tensioner pulleys, right?

G.
I am all about high-speed, low-drag, mid-drives and gears...
A-1B trike, 6+kW, 65+mph (Cyclone powered): https://www.youtube.com/watch?v=oFC8MRwvgUM
A-2A trike 3kW, 50mph (Cyclone powered): https://www.youtube.com/watch?v=bNoqp0wl6Vo
eB-1C bike 3kW, 42mph (Cyclone powered): https://www.youtube.com/watch?v=_weSmz_h3Ig

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Chalo
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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Feb 07, 2016 2:43 pm

gman1971 wrote:
Chalo wrote:My guess is that a stack of 7 sprockets at 6-speed spacing would fit nicely on an 8/9/10-speed cassette body, and could be compatible with 1/8" BMX chain. You'd just have to add spacers to the stack to achieve 5.5mm intervals.
This is something worth considering... and making the derailleur thicker is only a matter of putting washers around the tensioner pulleys, right?
More that likely, you'll need to find slightly longer pulley bolts (for instance from an older, wider derailleur).
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Two speed gear box for e-cargo bicycles?

Post by Warren » Feb 07, 2016 3:31 pm

Chalo,

No need to guess what will work. Just look at the cog and spacer thicknesses listed here, and add them up.

http://www.sheldonbrown.com/cribsheet-spacing.html

Where you run into difficulty making this setup from existing parts is that the OEM cassettes with large cogs ( only 10-11 speed) are all built using spiders for the larger cogs, so it isn't as easy as using thicker spacers. My suggestion would be using cheap 8 speed cassettes

http://www.cambriabike.com/Sunrace-M66- ... 0SS125.asp

for all the cogs but the last one.

http://www.wolftoothcomponents.com/pages/giant-cog

The main downside is that even 7 speed cassettes have only 1.85 mm mm thick cogs, when a BMX chain can handle 3.2 mm thick cogs.

[edit] I just went out in the shed and pulled a NOS Dura-Ace 8 speed cassette out of the box. The cogs are 1.8 mm thick as Sheldon said. Two sandwiched together fit nicely into a new BMX chain. That chain fits nicely into a NOS Shimano 105 derailleur cage.

I would double up 8 speed cogs for all positions but the last one. I'd probably sacrifice a tooth and sandwich two of these together for the last cog.

http://www.ebay.com/itm/MTB-Tools-41-To ... 1664912556

These cogs doubled up, with two 10 speed spacers between every sandwiched pair of cogs would allow a five speed drivetrain of great strength. You could probably double shift a 10 speed shifter pretty easily,without needing to fill detents.

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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Feb 07, 2016 5:49 pm

The only guesswork is as to whether the chain will bravely coexist with what you wind up with.

Chains wear out sprockets, rather than the other way around. Once a sprocket is badly worn, then it can wreck a chain. So the thickness of the sprocket is much less important than the width of the chain bushing surface.

A narrower sprocket leaves more room for a 1/8" chain to deflect sideways before contacting the adjacent sprocket. So a wider sprocket isn't necessarily an advantage.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Two speed gear box for e-cargo bicycles?

Post by gman1971 » Feb 07, 2016 11:51 pm

Chalo wrote:The only guesswork is as to whether the chain will bravely coexist with what you wind up with.

Chains wear out sprockets, rather than the other way around. Once a sprocket is badly worn, then it can wreck a chain. So the thickness of the sprocket is much less important than the width of the chain bushing surface.

A narrower sprocket leaves more room for a 1/8" chain to deflect sideways before contacting the adjacent sprocket. So a wider sprocket isn't necessarily an advantage.
Interesting thought... why would you want sideway deflection?

G.
I am all about high-speed, low-drag, mid-drives and gears...
A-1B trike, 6+kW, 65+mph (Cyclone powered): https://www.youtube.com/watch?v=oFC8MRwvgUM
A-2A trike 3kW, 50mph (Cyclone powered): https://www.youtube.com/watch?v=bNoqp0wl6Vo
eB-1C bike 3kW, 42mph (Cyclone powered): https://www.youtube.com/watch?v=_weSmz_h3Ig

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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Feb 08, 2016 12:59 am

gman1971 wrote:
Chalo wrote:A narrower sprocket leaves more room for a 1/8" chain to deflect sideways before contacting the adjacent sprocket. So a wider sprocket isn't necessarily an advantage.
Interesting thought... why would you want sideway deflection?
Because a chainring can only be aligned with (at most) a single sprocket. When the chain runs to any other rear sprocket, it departs at an angle rather than parallel to the sprocket. That angle uses up clearance between chain and adjacent sprockets.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Two speed gear box for e-cargo bicycles?

Post by turbo1889 » Feb 08, 2016 1:19 am

If you only need two speeds have you considered using a retro-direct type system on the motor output shaft. First put a left hand threaded 1.37x24t freewheel shaft adapter mount fitted with a south paw 24t freewheel on the motor shaft followed by a 30mm right hand thread freewheel with a heavy duty 13t right hand smaller size right hand freewheel mounted. Big 50+ tooth drive sprocket made using an over-sized chain wheel on the wheel or shaft to be driven. Run the chain around the big to be driven big 50+ toother then over to the motor and around the 13t right hand outer sprocket and back to a bearing-ed idler sprocket mounted a little ways away from the motor and around that idler sprocket and back to the motor this time wrapping around the larger south paw freewheel and then back to to connect with the other end of the chain on the other side of the big 50+ tooth.

----- Motor spins CCW it engages the 13t small size freewheel and pulls the chain with it 13t/50+t reduction ratio (AKA=low gear) and the 24t south paw freewheel just freewheels going along with the chain.
----- Motor spins CW it engages the 24t south paw freewheel and pulls the chain with it 24t/50+t reduction ratio (AKA=high gear) and the 13t small size freewheel just freewheels going along with the chain.

Just take a look at the diagram on the wiki page I linked too and envision the big chain wheel on the crank as being what your trying to drive and the motor mounted where the wheel is with the two freewheels one behind the other, one a righty and the other a lefty.

Its possible and its been done before, its how the Xionda and SRAM two speed hub motors work. You just need a controller with drive direction switch reversing leads which becomes a high/low switch instead.

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 08, 2016 2:17 am

turbo1889 wrote:If you only need two speeds have you considered using a retro-direct type system on the motor output shaft.
Coincidentally, spinningmagnets got in touch with me about this, yesterday! https://endless-sphere.com/forums/viewt ... =28&t=7679

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Re: Two speed gear box for e-cargo bicycles?

Post by Warren » Feb 08, 2016 10:00 am

Yup. Once you get over 1000 watts you are past current bicycle drive trains and a 2:1, two speed, retro direct makes perfect sense. If you still like to pedal along, like me, run it on the left side, and leave the right side for standard bicycle drive.

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Re: Two speed gear box for e-cargo bicycles?

Post by gman1971 » Feb 08, 2016 11:17 am

Warren wrote:Yup. Once you get over 1000 watts you are past current bicycle drive trains and a 2:1, two speed, retro direct makes perfect sense. If you still like to pedal along, like me, run it on the left side, and leave the right side for standard bicycle drive.
How hard is to do this? I mean, put something on the "left" side? do they sell sprockets that go with the disc brake?

G.
I am all about high-speed, low-drag, mid-drives and gears...
A-1B trike, 6+kW, 65+mph (Cyclone powered): https://www.youtube.com/watch?v=oFC8MRwvgUM
A-2A trike 3kW, 50mph (Cyclone powered): https://www.youtube.com/watch?v=bNoqp0wl6Vo
eB-1C bike 3kW, 42mph (Cyclone powered): https://www.youtube.com/watch?v=_weSmz_h3Ig

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Re: Two speed gear box for e-cargo bicycles?

Post by Warren » Feb 08, 2016 3:28 pm

Matt/recumpence makes an adapter.

https://www.electricbike.com/wp-content ... inring.jpg

Quite a few gas bicycle kits use left side sprockets which you might be able to adapt.

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Re: Two speed gear box for e-cargo bicycles?

Post by Tony01 » Feb 13, 2016 8:16 am

Find a 2-speed freewheel. Like this ebay- SUNTOUR-FREEWHEEL-2-SPD-16-20-HOLE-SHOT-BMX-RACE-RACING-cruiser-freestyle-NOS. I think this is your best bet and the lightest too. One of these older 2-sp FWs will let you use heavier duty BMX chain.

Retro direct is cool too.

BUT, do you want engine braking in one gear? If the answer is yes, read on.

I have experience with an auto shift freewheel+clutch 2-speed. For a bike that goes under 40mph this is about the best setup one can ask for (IMO). There is a 3d drawing of one a page or two back in this thread utilizing two input chains/belts with the different ratios; 1st gear driving a FW and 2nd gear driving a cent' clutch.

A word of caution: design your gear reduction carefully. Used as a 2-speed 2nd gear clutch, the minimum shift RPM for a kart clutch happens approximately 2-300rpm later than it is rated for likely because of the heightened load. With a MaxTorque clutch, using the light yellow spring and 6 heavy shoes, the "shift" rpm will happen around 1750rpm (compared to 1500rpm engagement when used on an engine jackshaft). So, if you're running a jackshaft setup with a motor shaft coming out both sides, you'll need to have most of your reduction coming from the jackshaft to the rear wheel in order to keep the RPMs up on the jackshaft to facilitate a shift at a reasonable slow speed. Too much reduction from motor to jackshaft will cause the minimum shift rpm to happen at higher driving speed and will be extremely annoying when you get stuck behind an asian driver who insists on driving *exactly* the 30mph speed limit.
I don't always listen to Alice in Chains.... but when I do, SO DO THE NEIGHBORS :D
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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 13, 2016 9:14 am


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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Feb 13, 2016 2:17 pm

I like the retro direct idea. But I did find this video
https://www.youtube.com/watch?v=Ver7yDgc6-8

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 13, 2016 2:25 pm

beginner01 wrote:Find a 2-speed freewheel. Like this ebay- SUNTOUR-FREEWHEEL-2-SPD-16-20-HOLE-SHOT-BMX-RACE-RACING-cruiser-freestyle-NOS. I think this is your best bet and the lightest too. One of these older 2-sp FWs will let you use heavier duty BMX chain.
Maybe we need to resurrect this project? https://endless-sphere.com/forums/viewt ... 50#p447150



Image

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Feb 13, 2016 2:40 pm

a three speed cassette? sounds interesting.

Miles wrote:
beginner01 wrote:Find a 2-speed freewheel. Like this ebay- SUNTOUR-FREEWHEEL-2-SPD-16-20-HOLE-SHOT-BMX-RACE-RACING-cruiser-freestyle-NOS. I think this is your best bet and the lightest too. One of these older 2-sp FWs will let you use heavier duty BMX chain.
Maybe we need to resurrect this project? https://endless-sphere.com/forums/viewt ... 50#p447150

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 13, 2016 2:50 pm

Could be 5 speed....
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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 14, 2016 8:46 am

Warren,

Think of it as a pre-echo from 2011. :)

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Re: Two speed gear box for e-cargo bicycles?

Post by Warren » Feb 14, 2016 10:48 am

OK. So who has the programming skills to get some water jet cogs cut from 3 mm stainless? :-)

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 14, 2016 11:04 am

All you need is a DXF file....

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Re: Two speed gear box for e-cargo bicycles?

Post by Warren » Feb 14, 2016 11:37 am

Miles,

"All you need is a DXF file...."

Is that anything like a mill bastard? :-) Seriously, I struggle with email. Just think of CAD stuff makes my palms sweat.

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Feb 14, 2016 11:59 am

:lol:

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

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