Linear-drive bicycles - home-building?

DougC said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't
/need/ to build them, single-speed freewheel cogs are already available
from Shimano for roughly $10 each.

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?

Linear drive? Like a "rail gun"?? Sounds fast.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't /need/
to build them, single-speed freewheel cogs are already available from
Shimano for roughly $10 each.

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?
~

DougC,
I think Carl Fogel has posted photos of this type of drive, but here is a
diagram:
http://www.geometricbikes.com/images/how-it-works_big.jpg
Kerry

On Mon, 15 Oct 2007 18:11:59 -0500, A Muzi <[email hidden]>

Quoted message said:

DougC said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't
/need/ to build them, single-speed freewheel cogs are already available
from Shimano for roughly $10 each.

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?

Linear drive? Like a "rail gun"?? Sounds fast.

Dear Andrew,

Possibly treadle-drive?

http://americanhistory.si.edu/ONTHEMOVE/collection/object_282.html

http://americanhistory.si.edu/ONTHEMOVE/collection/object_283.html

http://americanhistory.si.edu/ONTHEMOVE/collection/object_294.html

Cheers,

Carl Fogel

Kerry Montgomery said:

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't /need/
to build them, single-speed freewheel cogs are already available from
Shimano for roughly $10 each.

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?
~

DougC,
I think Carl Fogel has posted photos of this type of drive, but here is a
diagram:
http://www.geometricbikes.com/images/how-it-works_big.jpg
Kerry

Dear Kerry,

Possibly the Lattimer?

http://i9.tinypic.com/4taqys4.jpg

Cheers,

Carl Fogel

Kerry Montgomery said:

Quoted message said:

I am curious about building a linear-drive bicycle. I hadn't
bothered much with the idea because I didn't know how to build the
freewheeling mechanisms, but lately I've found out that I don't
/need/ to build them, single-speed freewheel cogs are already
available from Shimano for roughly $10 each.

....except that they are right handed and work only on the right side.

Quoted message said:

Quoted message said:

I have no idea how these would be used with anything else
however. Are there any websites showing someone constructing a
similar drive vehicle with them? ~

Quoted message said:

I think Carl Fogel has posted photos of this type of drive, but here
is a diagram:

Quoted message said:

http://www.geometricbikes.com/images/how-it-works_big.jpg

This is the mechanism Alenax all over again. This bicycle was at
InterBike again this year but with independent rotary cranks. That
is, each crank had a roller clutch (freewheel) so that they were not
phased to one another as conventional bicycle cranks are (180°) apart.

This got them over the step-function from zero to crank speed at the
ends of the stroke (if pedaling continuously) but it did not get them
over the both-pedals-to-the-bottom effect when standing up, which did
not raise the rider from the saddle (unless it was too low).

http://www.sheldonbrown.com/brandt/alenax.html

That all machinery that converts linear to circular motion uses cranks
should not overlook that reason. As In a piston engine, the legs also
have a finite stroke and inertia, so sinusoidal motion of a crank is
ideal. A linear pedal is exactly the opposite from what the device
needs.

Jobst Brandt

Kerry Montgomery said:

"DougC" <[email hidden]> wrote in message

news:[email hidden]...

Quoted message said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't /need/
to build them, single-speed freewheel cogs are already available from
Shimano for roughly $10 each.

Quoted message said:

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?
~

DougC,
I think Carl Fogel has posted photos of this type of drive, but here is a
diagram:http://www.geometricbikes.com/images/how-it-works_big.jpg
Kerry

if this kind of thing is what the OP had in mind, and all that's
needed for the hub and cogs is basically 2 same-size freewheels whose
mechanisms mirror each other on either side of the hub, you could use
a bmx flipflop hub with left drive on one side and right on the other.
i'm pretty sure i've seen metric/metric ones like this, which isn't
optimal because the cog size would be limited to 13t. assuming they
exist, they were always pretty uncommon, and it will be hard to find a
quality one in good shape now. metric/normal with the metric side
leftdrive is very common, but you need the same size cog so that's no
good. you could also turn one of these to be metric/metric, which
might be a decent plan since it's currently easy enough to get a new,
good one. ideal would be normal/normal, but i'm not sure that exists
with a leftdrive/rightdrive split, although 16t leftdrive freewheels
do exist. i'm sure phil could also easily make you a normal/normal
left/right drive ff hub, if it's budgetable. that way it wouldn't have
to be 14mm, too.

Quoted message said:

Kerry Montgomery said:

Quoted message said:

I am curious about building a linear-drive bicycle. I hadn't
bothered much with the idea because I didn't know how to build the
freewheeling mechanisms, but lately I've found out that I don't
/need/ to build them, single-speed freewheel cogs are already
available from Shimano for roughly $10 each.

...except that they are right handed and work only on the right side.

[snip]

Dear Jobst,

Luckily, you can get left and right versions of single-speed freewheel
in the BMX world.

As has been previously discussed, there are _two_ sides to this issue:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

The link in that post to left-side freewheels has died.

So here's a page that shows the normal (right-side) ACS single-speed
freewheel and the abnormal (left-side) ACS single-speed South-Paw
claw:

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCategory=322&idParent=62

,sreehC

Carl Fogel

Carl Fogel said:

Quoted message said:

Quoted message said:

> I am curious about building a linear-drive bicycle. I hadn't
> bothered much with the idea because I didn't know how to build the
> freewheeling mechanisms, but lately I've found out that I don't
> /need/ to build them, single-speed freewheel cogs are already
> available from Shimano for roughly $10 each.

Quoted message said:

Quoted message said:

...except that they are right handed and work only on the right side.

Quoted message said:

Luckily, you can get left and right versions of single-speed freewheel
in the BMX world.

Quoted message said:

As has been previously discussed, there are _two_ sides to this issue:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

The link in that post to left-side freewheels has died.

Quoted message said:

So here's a page that shows the normal (right-side) ACS single-speed
freewheel and the abnormal (left-side) ACS single-speed South-Paw
claw:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProduct=310&idParent=62

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCategory=322&idParent=62

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Jobst Brandt

Quoted message said:

Carl Fogel said:

Quoted message said:

>> I am curious about building a linear-drive bicycle. I hadn't
>> bothered much with the idea because I didn't know how to build the
>> freewheeling mechanisms, but lately I've found out that I don't
>> /need/ to build them, single-speed freewheel cogs are already
>> available from Shimano for roughly $10 each.

Quoted message said:

Quoted message said:

...except that they are right handed and work only on the right side.

Quoted message said:

Luckily, you can get left and right versions of single-speed freewheel
in the BMX world.

Quoted message said:

As has been previously discussed, there are _two_ sides to this issue:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

The link in that post to left-side freewheels has died.

Quoted message said:

So here's a page that shows the normal (right-side) ACS single-speed
freewheel and the abnormal (left-side) ACS single-speed South-Paw
claw:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProduct=310&idParent=62

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCategory=322&idParent=62

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Jobst Brandt

Dear Jobst,

Yes, they do make hubs for the left-hand drive freewheel:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProduct=258&idParent=96

But I'd be surprised if they make a hub that's dual-sided.

That is, you can get a left (abnormal) or a right (normal), but
probably not both together.

Maybe you could buy one of each and combine parts, but I suspect that
such weird hubs are probably made from scratch by tricking someone
like Chalo into running his lathe at midnight while uttering the
Lord's Prayer backwards.

Cheers,

Carl Fogel

Quoted message said:

Quoted message said:

Carl Fogel said:

>>> I am curious about building a linear-drive bicycle. I hadn't
>>> bothered much with the idea because I didn't know how to build the
>>> freewheeling mechanisms, but lately I've found out that I don't
>>> /need/ to build them, single-speed freewheel cogs are already
>>> available from Shimano for roughly $10 each.
> ...except that they are right handed and work only on the right side.
Luckily, you can get left and right versions of single-speed freewheel
in the BMX world.
As has been previously discussed, there are _two_ sides to this issue:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

The link in that post to left-side freewheels has died.
So here's a page that shows the normal (right-side) ACS single-speed
freewheel and the abnormal (left-side) ACS single-speed South-Paw
claw:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProduct=310&idParent=62

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCategory=322&idParent=62

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Jobst Brandt

Dear Jobst,

Yes, they do make hubs for the left-hand drive freewheel:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProduct=258&idParent=96

But I'd be surprised if they make a hub that's dual-sided.

That is, you can get a left (abnormal) or a right (normal), but
probably not both together.

Maybe you could buy one of each and combine parts, but I suspect that
such weird hubs are probably made from scratch by tricking someone
like Chalo into running his lathe at midnight while uttering the
Lord's Prayer backwards.

Cheers,

Carl Fogel

I don't want to fix the two "added" freewheels to both sides of the rear
wheel at all. What I'm imagining is a way to functionally place them on
a jackshaft, and then use the jackshaft to spin a conventional BB
somehow--such as by using another cog and chain over the granny ring.

This would be for a recumbent bike anyway, so the added drivetrain
length wouldn't be a problem. I've only see this on a couple of IHPVA
type streamliner recumbents--and not any of the current ones, so I don't
suspect it's going to result in a higher power output.

I am quite intrigued by a drivetrain that lets you use whatever stroke
you wish. I suspect it would make the bicycle much less fit-critical,
and may end up being more comfortable in use.
~

Quoted message said:

Quoted message said:

Carl Fogel writes:

Quoted message said:

Quoted message said:

>>> I am curious about building a linear-drive bicycle. I hadn't
>>> bothered much with the idea because I didn't know how to build the
>>> freewheeling mechanisms, but lately I've found out that I don't
>>> /need/ to build them, single-speed freewheel cogs are already
>>> available from Shimano for roughly $10 each.

Quoted message said:

Quoted message said:

>...except that they are right handed and work only on the right side.

Quoted message said:

Quoted message said:

Luckily, you can get left and right versions of single-speed freewheel
in the BMX world.

Quoted message said:

Quoted message said:

As has been previously discussed, there are _two_ sides to this issue:

Quoted message said:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

Quoted message said:

The link in that post to left-side freewheels has died.

Quoted message said:

Quoted message said:

So here's a page that shows the normal (right-side) ACS single-speed
freewheel and the abnormal (left-side) ACS single-speed South-Paw
claw:

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCat...

Quoted message said:

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Quoted message said:

Jobst Brandt

Dear Jobst,

Yes, they do make hubs for the left-hand drive freewheel:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

But I'd be surprised if they make a hub that's dual-sided.

they are common. much more common than either single-sided or left/
left freewheel hubs, as numerous bikes come oem with them.

http://en.wikipedia.org/wiki/Flip-flop_hub

one thing this article perhaps has wrong is saying that the 16t
southpaw is the most common leftdrive fw. in actuality it's probably
the ody 13t, ime.

On Mon, 15 Oct 2007 20:43:57 -0700, Nate Knutson <[email hidden]>

Quoted message said:

Quoted message said:

Quoted message said:

Carl Fogel writes:

Quoted message said:

>>>> I am curious about building a linear-drive bicycle. I hadn't
>>>> bothered much with the idea because I didn't know how to build the
>>>> freewheeling mechanisms, but lately I've found out that I don't
>>>> /need/ to build them, single-speed freewheel cogs are already
>>>> available from Shimano for roughly $10 each.

Quoted message said:

>>...except that they are right handed and work only on the right side.

Quoted message said:

> Luckily, you can get left and right versions of single-speed freewheel
> in the BMX world.

Quoted message said:

> As has been previously discussed, there are _two_ sides to this issue:

Quoted message said:

http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

> The link in that post to left-side freewheels has died.

Quoted message said:

> So here's a page that shows the normal (right-side) ACS single-speed
> freewheel and the abnormal (left-side) ACS single-speed South-Paw
> claw:

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCat...

Quoted message said:

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Quoted message said:

Jobst Brandt

Dear Jobst,

Yes, they do make hubs for the left-hand drive freewheel:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

But I'd be surprised if they make a hub that's dual-sided.

they are common. much more common than either single-sided or left/
left freewheel hubs, as numerous bikes come oem with them.

http://en.wikipedia.org/wiki/Flip-flop_hub

one thing this article perhaps has wrong is saying that the 16t
southpaw is the most common leftdrive fw. in actuality it's probably
the ody 13t, ime.

Dear Nate,

You're right and I'm wrong (or at least surprised).

I was just flat mistaken about the threading on the flip-flop. I
assumed that it was the same on both sides, but the article that you
link to says no, opposite threading.

What I overlooked (I think) is that one gear is fixed (probably the
lower for climbing) and the other freewheels (probably the higher for
coasting on descents and flats), so unscrewing would be a problem.

Thanks for surprising me!

Cheers,

Carl Fogel

DougC said:

I am curious about building a linear-drive bicycle.
I hadn't bothered much with the idea because I didn't know how to build
the freewheeling mechanisms, but lately I've found out that I don't
/need/ to build them, single-speed freewheel cogs are already available
from Shimano for roughly $10 each.

I have no idea how these would be used with anything else however. Are
there any websites showing someone constructing a similar drive vehicle
with them?
~

Joe Kochanowski built a semi-linear drive recumbent, visible on this
page:
http://www.outsideconnection.com/gallant/hpv/joe/
with an action video at
http://www.outsideconnection.com/gallant/hpv/joe/linearDrive.mpg

There's also the "K-drive":
http://web.uct.ac.za/depts/psychology/bok/kdrive.html

Various forms of linear drives have been tried in human-powered
vehicle competitions over the years. None has been successful. All of
the vehicles at this year's World Human Powered Speed Challenge used a
circular crank motion, even if other drivetrain details were all over
the place.

Jeff

Quoted message said:

On Mon, 15 Oct 2007 20:43:57 -0700, Nate Knutson <[email hidden]>

Quoted message said:

Quoted message said:

On 16 Oct 2007 01:46:22 GMT, [email hidden] wrote:

Quoted message said:

Quoted message said:

>Carl Fogel writes:

Quoted message said:

Quoted message said:

>>>>> I am curious about building a linear-drive bicycle. I hadn't
>>>>> bothered much with the idea because I didn't know how to build the
>>>>> freewheeling mechanisms, but lately I've found out that I don't
>>>>> /need/ to build them, single-speed freewheel cogs are already
>>>>> available from Shimano for roughly $10 each.

Quoted message said:

Quoted message said:

>>>...except that they are right handed and work only on the right side.

Quoted message said:

Quoted message said:

>> Luckily, you can get left and right versions of single-speed freewheel
>> in the BMX world.

Quoted message said:

Quoted message said:

>> As has been previously discussed, there are _two_ sides to this issue:

Quoted message said:

Quoted message said:

>http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

Quoted message said:

>> The link in that post to left-side freewheels has died.

Quoted message said:

Quoted message said:

>> So here's a page that shows the normal (right-side) ACS single-speed
>> freewheel and the abnormal (left-side) ACS single-speed South-Paw
>> claw:

Quoted message said:

Quoted message said:

>http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

Quoted message said:

>http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCat...

Quoted message said:

Quoted message said:

>Well you'll need a hub with left hand threads on the left side. I
>suppose those must be around or they wouldn't make freewheels for
>them.

Quoted message said:

Quoted message said:

>Jobst Brandt

Quoted message said:

Quoted message said:

Dear Jobst,

Quoted message said:

Quoted message said:

Yes, they do make hubs for the left-hand drive freewheel:

Quoted message said:

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

Quoted message said:

But I'd be surprised if they make a hub that's dual-sided.

Quoted message said:

they are common. much more common than either single-sided or left/
left freewheel hubs, as numerous bikes come oem with them.

Quoted message said:

http://en.wikipedia.org/wiki/Flip-flop_hub

Quoted message said:

one thing this article perhaps has wrong is saying that the 16t
southpaw is the most common leftdrive fw. in actuality it's probably
the ody 13t, ime.

Dear Nate,

You're right and I'm wrong (or at least surprised).

I was just flat mistaken about the threading on the flip-flop. I
assumed that it was the same on both sides, but the article that you
link to says no, opposite threading.

What I overlooked (I think) is that one gear is fixed (probably the
lower for climbing) and the other freewheels (probably the higher for
coasting on descents and flats), so unscrewing would be a problem.

fixed gears aren't involved (unless someone decides to be eccentric).
also, bmx riders generally don't use flipflop hubs for the sake of
having different gears to choose from. the benefit of a flipfop hub is
either that it can take both iso and metric in one drive orientation
(this is the most common), or so that it can be left/right with the
same thread size on both (but different handedness, of course), or so
that it can be a right/normal and left/metric split. in other words,
it might be chosen by the rider for versatility, by whoever's stocking
the wheel for it's ability to fill different needs, or by the bike
company (and industry as a whole) to provide an upgrade path (smaller
gearing, in the most common case of a normal/metric rh-drive flipflop
hub).

JeffWills said:

Joe Kochanowski built a semi-linear drive recumbent, visible on this
page:
http://www.outsideconnection.com/gallant/hpv/joe/
with an action video at
http://www.outsideconnection.com/gallant/hpv/joe/linearDrive.mpg

There's also the "K-drive":
http://web.uct.ac.za/depts/psychology/bok/kdrive.html

Neither of these allows variable-length pedal strokes, however. They are
only variants based on conventional pedal cranks.

Quoted message said:

Various forms of linear drives have been tried in human-powered
vehicle competitions over the years. None has been successful. All of
the vehicles at this year's World Human Powered Speed Challenge used a
circular crank motion, even if other drivetrain details were all over
the place.

Power output is not my particular goal, riding comfort is--though I
suspect that allowing variable-length strokes WOULD improve power output
for most average riders. When people jog over varied terrain, they do
not use the same stride length over all terrain, or even throughout the
total distance--but conventional bicycles force you to use the same
length of pedal stroke all the time.

The Sherer trike approaches what I'm imagining, except that I don't have
much interest in a trike, and I don't want to pay $4200+ for such a
setup either.

http://www.shererusa.com/page2.html

What I'm interested is how exactly those freewheels have to be attached
to function.
~

DougC said:

Quoted message said:

On 16 Oct 2007 01:46:22 GMT, [email hidden] wrote:

Quoted message said:

Quoted message said:

Carl Fogel writes:

Quoted message said:

Quoted message said:

>>>> I am curious about building a linear-drive bicycle. I hadn't
>>>> bothered much with the idea because I didn't know how to build the
>>>> freewheeling mechanisms, but lately I've found out that I don't
>>>> /need/ to build them, single-speed freewheel cogs are already
>>>> available from Shimano for roughly $10 each.
>> ...except that they are right handed and work only on the right side.
> Luckily, you can get left and right versions of single-speed freewheel
> in the BMX world.
> As has been previously discussed, there are _two_ sides to this issue:
http://groups.google.com/group/rec.bicycles.tech/msg/adfadf06467f4d44

Quoted message said:

Quoted message said:

> The link in that post to left-side freewheels has died.
> So here's a page that shows the normal (right-side) ACS single-speed
> freewheel and the abnormal (left-side) ACS single-speed South-Paw
> claw:
http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_listItems.asp?idCat...

Quoted message said:

Quoted message said:

Well you'll need a hub with left hand threads on the left side. I
suppose those must be around or they wouldn't make freewheels for
them.

Quoted message said:

Quoted message said:

Jobst Brandt

Quoted message said:

Dear Jobst,

Quoted message said:

Yes, they do make hubs for the left-hand drive freewheel:

Quoted message said:

http://distro.1664bmx.com/comersus/store/comersus_viewItem.asp?idProd...

Quoted message said:

But I'd be surprised if they make a hub that's dual-sided.

Quoted message said:

That is, you can get a left (abnormal) or a right (normal), but
probably not both together.

Quoted message said:

Maybe you could buy one of each and combine parts, but I suspect that
such weird hubs are probably made from scratch by tricking someone
like Chalo into running his lathe at midnight while uttering the
Lord's Prayer backwards.

Quoted message said:

Cheers,

Quoted message said:

Carl Fogel

I don't want to fix the two "added" freewheels to both sides of the rear
wheel at all. What I'm imagining is a way to functionally place them on
a jackshaft, and then use the jackshaft to spin a conventional BB
somehow--such as by using another cog and chain over the granny ring.

This would be for a recumbent bike anyway, so the added drivetrain
length wouldn't be a problem. I've only see this on a couple of IHPVA
type streamliner recumbents--and not any of the current ones, so I don't
suspect it's going to result in a higher power output.

I am quite intrigued by a drivetrain that lets you use whatever stroke
you wish. I suspect it would make the bicycle much less fit-critical,
and may end up being more comfortable in use.
~

Why not forget about independent leg movement, and make one big pedal
for both feet? Kind of like a leg press machine. The drive train could
be simpler. Kind of like a stationary rowing machine.

Joseph

On 2007-10-16, [email hidden] <[email hidden]> wrote:
[...]

Quoted message said:

Why not forget about independent leg movement, and make one big pedal
for both feet? Kind of like a leg press machine. The drive train could
be simpler. Kind of like a stationary rowing machine.

Such things do exist. I passed someone once riding along on a recumbent
vehicle that was exactly that: a rowing machine bicycle.

He said he got it from the Netherlands.

Both the "pedals" that his feet were attached to and the handlebars were
attached to cables operating pulleys in some fashion, so he was pulling
back with his arms and pushing with his feet at the same time in an
authentic rowing action.

Here we are: http://www.rowingbike.com/main.php

I think it was one of those. Of course preferable to actual rowing
because you can see where you're going. It might be an idea to put one
in a boat connected to propellers...

Ben C said:

On 2007-10-16, [email hidden] <[email hidden]> wrote:
[...]

Quoted message said:

Why not forget about independent leg movement, and make one big pedal
for both feet? Kind of like a leg press machine. The drive train could
be simpler. Kind of like a stationary rowing machine.

Such things do exist. I passed someone once riding along on a recumbent
vehicle that was exactly that: a rowing machine bicycle.

He said he got it from the Netherlands.

Both the "pedals" that his feet were attached to and the handlebars were
attached to cables operating pulleys in some fashion, so he was pulling
back with his arms and pushing with his feet at the same time in an
authentic rowing action.

Here we are:http://www.rowingbike.com/main.php

I think it was one of those. Of course preferable to actual rowing
because you can see where you're going. It might be an idea to put one
in a boat connected to propellers...

My vote is for a submarine.

Joseph

"DougC" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

JeffWills said:

Joe Kochanowski built a semi-linear drive recumbent, visible on this
page:
http://www.outsideconnection.com/gallant/hpv/joe/
with an action video at
http://www.outsideconnection.com/gallant/hpv/joe/linearDrive.mpg

There's also the "K-drive":
http://web.uct.ac.za/depts/psychology/bok/kdrive.html

Neither of these allows variable-length pedal strokes, however. They are
only variants based on conventional pedal cranks.

Quoted message said:

Various forms of linear drives have been tried in human-powered
vehicle competitions over the years. None has been successful. All of
the vehicles at this year's World Human Powered Speed Challenge used a
circular crank motion, even if other drivetrain details were all over
the place.

Power output is not my particular goal, riding comfort is--though I
suspect that allowing variable-length strokes WOULD improve power output
for most average riders. When people jog over varied terrain, they do not
use the same stride length over all terrain, or even throughout the total
distance--but conventional bicycles force you to use the same length of
pedal stroke all the time.

The Sherer trike approaches what I'm imagining, except that I don't have
much interest in a trike, and I don't want to pay $4200+ for such a setup
either.

http://www.shererusa.com/page2.html

What I'm interested is how exactly those freewheels have to be attached to
function.
~

Hi DougC,
The freewheels just spin (thread) onto the BMX hub, a left-hand threaded
freewheel on the left side of the hub, and a right-handed freewheel on the
right side of the hub. Just like threading a nut onto a bolt.
If you use one of the double-sided BMX hubs that others have mentioned, just
spin the one of the appropriate freewheels on each side. Connect a chain to
the right side foot lever, run it over the top of the freewheel on the right
side of the hub, and connect the end of that chain to a spring that keeps
the chain taut when the foot lever is moving toward the hub. When the foot
lever is moving away from the hub, it will turn the hub. Do the same on the
left side.
Kerry