Will they ever make a bicycle with both left hand and right hand drives?

On 13/08/12 08:51, James wrote:
On 13/08/12 01:52, Jeff Liebermann wrote:
On Sun, 12 Aug 2012 08:32:00 +0100, Phil W
wrote:

They didn't even get close - schlumf front drive with a triple
chainring, driving a 9s cluster on a DualDrive triple hub gives
2x3x3x9, or 142 gears.
That's without putting an intermediate shaft with additional gears of
course, which, if you could fettle a rohloff in there, would be 1988
gears.

There's a point where a continuously variable transmission makes more
sense than adding gear ratios. For example:
http://fallbrooktechnologies.com/08_NuVinciExperience.asp


I don't think these are very efficient. They don't publish efficiency
figures, and have said they wont. I think it's going anywhere in it's
current form.


SB, I don't think it's going anywhere in it's current form.

--
JS.

On Aug 12, 4:05*pm, AMuzi wrote:
On 8/12/2012 4:38 PM, DirtRoadie wrote:









On Aug 12, 3:12 pm, AMuzi wrote:
On 8/12/2012 2:26 PM, DirtRoadie wrote:

On Sunday, August 12, 2012 11:49:47 AM UTC-6, AMuzi wrote:

Well, if you're starting down that path:

http://www.m-gineering.nl/retro1.jpg

Interesting, got any more info or links on that setup?
One of the features of that would appear to be to allow forward propulsion regardless of the direction of pedaling.
Reverse pedaling provides a lower gear ratio.
DR

Yes, that's correct. It's an old simple clever design.
Do you know any details? Builder's name? (or others like it?) *Date?
Patents?
DR

It's Hirondelle (swallow) and the drive is retro-direct.

I'm not the expert, just ran across one 40 years ago.
for further reading:

http://www.devilfinder.com/find.php?...ndelle+bicycle

--
Andrew Muzi
* www.yellowjersey.org/
* Open every day since 1 April, 1971

Thanks very much. Amazing how much information suddenly becomes
available when a specific term can be used.
For example:
http://en.wikipedia.org/wiki/Retro-direct
DR

On Mon, 13 Aug 2012 08:51:41 +1000, James
wrote:

On 13/08/12 01:52, Jeff Liebermann wrote:
On Sun, 12 Aug 2012 08:32:00 +0100, Phil W
wrote:

They didn't even get close - schlumf front drive with a triple
chainring, driving a 9s cluster on a DualDrive triple hub gives
2x3x3x9, or 142 gears.
That's without putting an intermediate shaft with additional gears of
course, which, if you could fettle a rohloff in there, would be 1988
gears.

There's a point where a continuously variable transmission makes more
sense than adding gear ratios. For example:
http://fallbrooktechnologies.com/08_NuVinciExperience.asp

I don't think these are very efficient. They don't publish efficiency
figures, and have said they wont. I think it's going anywhere in it's
current form.

http://en.wikipedia.org/wiki/NuVinci_Continuously_Variable_Transmission
...NuVinci CVT were only 85% as efficient as the conventional
transmission it replaced, the gain in operating efficiency
from the power plant would have to be 18%
(i.e., 1/0.85 - 1 = 0.18 or 18%) before the overall
efficiency improved...

The mechanism is floating in a bistable fluid of some sorts. When the
fluid is compressed between the balls and the drive race surface, the
fluid momentarily turns hard, which provides the necessary drive
friction.
http://en.wikipedia.org/wiki/Non-Newtonian_fluid
http://en.wikipedia.org/wiki/Shear_thickening
Elsewhere in the mechanism, it's like having the gearbox immersed in
viscous oil. No clue on the normal viscosity, but there's going to be
plenty of drag with any fluid because of adjacent counter rotating
balls.

However, as an alternative to the multitude of gears necessary to get
the same effect using conventional chain drive mechanics, it does have
the advantages of simplicity, ellegance, a sealed mechanism, and the
equivalent of close gear spacing. In some applications, such as
"utility" bicycles, auto-shifting bicycles, and robotic machines, some
drag can probably be tolerated in trade for ease of gear changing.

I've never ridden one but sounds like it's worth a try.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 12 Aug 2012 20:17:49 -0700 (PDT), DirtRoadie
wrote:

Thanks very much. Amazing how much information suddenly becomes
available when a specific term can be used.
For example:
http://en.wikipedia.org/wiki/Retro-direct
DR

A little digging found yet another name for it. Tri Via Gearing
system.
http://www.frankb.us/gears/
There's also a Yahoo group:
http://sports.groups.yahoo.com/group/retro-direct/
but it appears abandoned because all the messages are spam.

Here's a cruiser conversion:
http://bikerodnkustom3.homestead.com/Lingo_retrodirect.html
Hmmm... no front brake.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 13/08/12 13:20, Jeff Liebermann wrote:
On Mon, 13 Aug 2012 08:51:41 +1000,
wrote:

On 13/08/12 01:52, Jeff Liebermann wrote:
On Sun, 12 Aug 2012 08:32:00 +0100, Phil W
wrote:

They didn't even get close - schlumf front drive with a triple
chainring, driving a 9s cluster on a DualDrive triple hub gives
2x3x3x9, or 142 gears.
That's without putting an intermediate shaft with additional gears of
course, which, if you could fettle a rohloff in there, would be 1988
gears.

There's a point where a continuously variable transmission makes more
sense than adding gear ratios. For example:
http://fallbrooktechnologies.com/08_NuVinciExperience.asp

I don't think these are very efficient. They don't publish efficiency
figures, and have said they wont. I think it's going anywhere in it's
current form.

http://en.wikipedia.org/wiki/NuVinci_Continuously_Variable_Transmission
...NuVinci CVT were only 85% as efficient as the conventional
transmission it replaced, the gain in operating efficiency
from the power plant would have to be 18%
(i.e., 1/0.85 - 1 = 0.18 or 18%) before the overall
efficiency improved...

_were_ only. They have a new model I believe and have stated that they
will not release efficiency information. There may be folks who have
performed their own tests. 85% is not considered efficient compared
with what we have now.

http://nuvinci.informe.com/forum/post1138.html?start=0

The mechanism is floating in a bistable fluid of some sorts. When the
fluid is compressed between the balls and the drive race surface, the
fluid momentarily turns hard, which provides the necessary drive
friction.
http://en.wikipedia.org/wiki/Non-Newtonian_fluid
http://en.wikipedia.org/wiki/Shear_thickening
Elsewhere in the mechanism, it's like having the gearbox immersed in
viscous oil. No clue on the normal viscosity, but there's going to be
plenty of drag with any fluid because of adjacent counter rotating
balls.

However, as an alternative to the multitude of gears necessary to get
the same effect using conventional chain drive mechanics, it does have
the advantages of simplicity, ellegance, a sealed mechanism, and the
equivalent of close gear spacing. In some applications, such as
"utility" bicycles, auto-shifting bicycles, and robotic machines, some
drag can probably be tolerated in trade for ease of gear changing.

I've never ridden one but sounds like it's worth a try.


You can't get the same effect with traditional gears. Chains have a
finite width.

Sealed? How do you get an axle and gear change control actuator in
there without a rubber seal or two? I guess it is about as sealed as
any other sealed bearing - only just enough to keep the weather out for
a while ;-)

Yes there are some pros, but not enough to tip the scales for most.

--
JS.

On Mon, 13 Aug 2012 14:11:05 +1000, James
wrote:

http://en.wikipedia.org/wiki/NuVinci_Continuously_Variable_Transmission
...NuVinci CVT were only 85% as efficient as the conventional
transmission it replaced, the gain in operating efficiency
from the power plant would have to be 18%
(i.e., 1/0.85 - 1 = 0.18 or 18%) before the overall
efficiency improved...

_were_ only. They have a new model I believe and have stated that they
will not release efficiency information. There may be folks who have
performed their own tests. 85% is not considered efficient compared
with what we have now.

Worse. That's 85% as efficient as a "conventional transmission it
replaced", not 85% overall drive efficiency. It has a long way to go
before it will be as efficient as a chain drive (up to 98%).

http://nuvinci.informe.com/forum/post1138.html?start=0

http://nuvinci.informe.com/forum/bicycle-hub-discussion-f3/surly-karate-monkey-w-n360-t437.html
Yuck. 1.78:1 maximum gear ratio. Not much use climbing steep hills.

Sealed? How do you get an axle and gear change control actuator in
there without a rubber seal or two? I guess it is about as sealed as
any other sealed bearing - only just enough to keep the weather out for
a while ;-)

Warranty void if used as a submarine. Sealing is always a problem. I
guess(tm) that since it's fluid filled, water won't accumulate inside.
Cleaning and fluid replacement looks like factory only. Hmmm...

Yes there are some pros, but not enough to tip the scales for most.

Probably true, but it still looks like fun to try. I think most of
the benefit is in confusing your friends and ride partners.

How to do it without butchering the frame using two chains:
http://myspace.voo.be/pcoupard/retrodirect_drive/

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 13/08/12 14:36, Jeff Liebermann wrote:

How to do it without butchering the frame using two chains:
http://myspace.voo.be/pcoupard/retrodirect_drive/


Does the pedal backwards cyclist qualify to register with the Ministry
of Silly Walks?

--
JS.

On Mon, 13 Aug 2012 15:01:50 +1000, James
wrote:

On 13/08/12 14:36, Jeff Liebermann wrote:

How to do it without butchering the frame using two chains:
http://myspace.voo.be/pcoupard/retrodirect_drive/

Does the pedal backwards cyclist qualify to register with the Ministry
of Silly Walks?

No. That's reserved for real backwards cyclists:
http://www.recordholders.org/en/records/backwards-cycling.html

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 12-8-2012 19:49, AMuzi wrote:
On 8/12/2012 10:41 AM, Jeff Liebermann wrote:
On Sun, 12 Aug 2012 16:47:20 +0200, m-gineering
wrote:

been tried befo
http://www.cyclingburylancs.com/velocio.htm

Thanks. Some more photos:
http://www.flickr.com/photos/collectvelo/4743039511/
http://www.flickr.com/photos/collectvelo/4743679320/
http://theinquisition.eu/wordpress/wp-content/uploads/2011/05/velocio.jpg

How it works:
http://cycling.ahands.org/bicycling/velocio.html



Well, if you're starting down that path:

http://www.m-gineering.nl/retro1.jpg



full link:
http://www.m-gineering.nl/retrog.htm

--
/Marten

info(apestaartje)m-gineering(punt)nl

On 8/11/2012 6:25 PM, Frank Krygowski wrote:

First, I think few people really need more gears than what's available
from common derailleur systems. Second, if you really needed them, I
think there would be a better way to get them than a two-sided drive
system.[...]

Yes, the 2-speed Schlumpf bottom brackets are better than two chains, etc.

Few people includes velomobile riders, who can easily use a range of 10
to 150 gear inches, since there are obviously no low speed balance
issues, and no extra aerodynamic drag from pedaling (which make pedaling
above about 40 mph on a descent on an unfaired bicycle pointless).

If I wanted super-close increments between gears plus a super-wide
range, I think I'd look into mating a standard derailleur set with a
wide ratio 3-speed hub gear - and that's old technology. I remember
riding with one guy that had that back in the 1970s.

Does anyone know when the first Sachs 2x6 rear hub was introduced?

Followed of course by the Sachs/SRAM 3x7 hub, and 3x8 and 3x9 DualDrive
hubs.

However, adding the SRAM 3x7 hub only really adds a couple of extra
ratios to both top and bottom, with the rest being near duplicates in a
63-speed system. Very useful on a heavier but aerodynamic 'bent, however.

--
Tºm Shermªn - 42.435731°N, 83.985007°W
Post Free or Die!