crankset design

[email hidden] (Jeff Wills) wrote in message news:<[email hidden]>...
<snip>

Quoted message said:

There's been a couple versions of this- a plastic version that
appeared on the Yankee bicycle (I think) and an earlier version (late
70's - early 80's) that was nearly solid steel. Interesting idea- a
truly continuously variable transmission. It worked- but they required
backpedaling to downshift.

Stu clued me in on the earlier version. Here's a copy of a previous posting:

Quoted message said:

How to Fix your Bicycle
by the Technical Publications Division of Intertec Publishing Corp
copyright 1973, no ISBN

Another good tech book, and has some "cutting edge" stuff
like a Dana 3 spd
planetary system for the crankset(!) as well as a Hagen
variable ratio drive
with 6 derailer pulleys sliding in a spiral groove to change
the diameter of
the drive (not enough details to tell how it operates)

My partners at Aerocoupe had one of those Hagen beasties- the entire
crankset probably weighed ten pounds.

The chain rode on six star wheels (with built-in one-way clutches). The
spiral groove moved them into smaller or larger diameters by way of a
brake-like device that stopped the spiral plate from moving while another
plate with tangential grooves continued to drive the star wheels around.
The net effect was that if you stopped the spiral plate while pedaling
forward, your chainring got larger; while if you stopped the plate and
backpedaled, the chainring got smaller. Fascinating device, but I hate to
think what would happen to all those tight-tolerance grooves once they wore
a little.

I don't doubt that Larry Black has one around- probably in its original box.

Jeff

"SDMike" <[email hidden]> wrote in message news:<cj4Ec.17313$6r1.15826@fed1read06>...

Quoted message said:

<snip>

Quoted message said:

Excuse me, but let's get this straight. YOU are the one questioning whether
the "efficiency" of today's cranks. I would argue that it is YOU, not me or
anyone else, but YOU who must prove there is a *better solution*.

Where do you get off thinking that the current design is not efficient. What
proof do you have? Is it the fact that maybe YOU are so out of shape that
you can't climb a hill that you now seek some sort of solution? Perhaps
you're thinking that with this *better* design that you will be able to keep
up with someone like say Lance Armstrong. Dream on buddy. Until you can show
evidence that the current design is insufficent - and yes, we would want
both your "mathematics" and "physics" behind your claims, keep dreaming.....

Geez! Who [censored] in your wheaties this morning?

Hey M,
Thanks for the <snip>!! You basically took out the OP statement that
anyone who supports the "current" crankset design needs to prove
"mathematical" support to prove its the most efficient. Sorry, but
since he's the one questioning the efficiency of today's crank design,
he need to prove its not efficient!

<snip>

Quoted message said:

Quoted message said:

Geez! Who [censored] in your wheaties this morning?

Hey M,
Thanks for the <snip>!! You basically took out the OP statement that
anyone who supports the "current" crankset design needs to prove
"mathematical" support to prove its the most efficient. Sorry, but
since he's the one questioning the efficiency of today's crank design,
he need to prove its not efficient!

I could care less if the crankset the guy's recommending has 2 separate
arm/side. There's more than one way to say "you're a farging idiot..." He
picked the not so nice one. Now, if he'd said politely, "please explain your
idea a little further. I'm having issues trying to figure out how this is going
to be a better system" no one would've jumped his [censored].

Now, I do agree that the guy needs to prove that his design in stiffer, lighter,
and easier to use. Somehow I doubt it will be, but you just never know!

M

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

Quoted message said:

"SDMike" wrote: Geez! Who [censored] in your wheaties this morning?
^^^^^^^^^^^^^
He may be using harsher words than necessary, but he happens to be right.
The things on a bicycle that can be improved are changing: indexed
shifting, increased number and range of ratios, decreased weight/improved
materials, etc. Probably the reason that the cranks have stayed the same is
that they work so well, in spite of their simplicity. If someone builds a
"better mousetrap," the cycling community will beat a path to his/her door.
It is not necessary to prove that improvements are still possible. They
prove themselves.

OK, maybe I have been a bit harsh. So, if the OP wants to redeem
himself, may be he can explain whether either of these 2 cranks work:

http://www.bikedrive.com/english/index.htm

http://www.powercranks.com/ (note - at least for me, this was a very
slow site)

bfd said:

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

Quoted message said:

"SDMike" wrote: Geez! Who [censored] in your wheaties this morning?
^^^^^^^^^^^^^
He may be using harsher words than necessary, but he happens to be right.
The things on a bicycle that can be improved are changing: indexed
shifting, increased number and range of ratios, decreased weight/improved
materials, etc. Probably the reason that the cranks have stayed the same is
that they work so well, in spite of their simplicity. If someone builds a
"better mousetrap," the cycling community will beat a path to his/her door.
It is not necessary to prove that improvements are still possible. They
prove themselves.

OK, maybe I have been a bit harsh. So, if the OP wants to redeem
himself, may be he can explain whether either of these 2 cranks work:

http://www.bikedrive.com/english/index.htm

http://www.powercranks.com/ (note - at least for me, this was a very
slow site)

Thanks to everybody for the input. I know that my idea wasn't a bright
(and not working) one, but my goal was just to investigate about what
other people did. Thanks to those who posted the pictures, there are
interesting things in those designs, of course the current crankset will
will be hard to beat, but who knows? Let's ride, we'll see! :-)

Francesco

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

Quoted message said:

"Francesco Devittori" <frenkatfrenkdtcm> wrote in message
news:[email hidden]...

Quoted message said:

bfd said:

>Francesco Devittori wrote:
>
>However I'm still curious about alternative desings...

Unless someone will mathematically prove that the current design is the
most efficient, the lightest and the most troublefree you can assume
that a better solution *could* exist.

Excuse me, but let's get this straight. YOU are the one questioning whether
the "efficiency" of today's cranks. I would argue that it is YOU, not me or
anyone else, but YOU who must prove there is a *better solution*.

Where do you get off thinking that the current design is not efficient. What
proof do you have? Is it the fact that maybe YOU are so out of shape that
you can't climb a hill that you now seek some sort of solution? Perhaps
you're thinking that with this *better* design that you will be able to keep
up with someone like say Lance Armstrong. Dream on buddy. Until you can show
evidence that the current design is insufficent - and yes, we would want
both your "mathematics" and "physics" behind your claims, keep dreaming.....

Goodness me. You ARE a cranky person aren't you!

Marty

Marty said:

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

Quoted message said:

Where do you get off thinking that the current design is not
efficient. What proof do you have? Is it the fact that maybe YOU are
so out of shape that you can't climb a hill that you now seek some
sort of solution? Perhaps you're thinking that with this *better*
design that you will be able to keep up with someone like say Lance
Armstrong. Dream on buddy. Until you can show evidence that the
current design is insufficent - and yes, we would want both your
"mathematics" and "physics" behind your claims, keep dreaming.....

Goodness me. You ARE a cranky person aren't you!

Pun intended?!?

Bill "think he already copped to being a tad grouchy" S.

Jeff Wills said:

[email hidden] (Jeff Wills) wrote in message
news:<[email hidden]>... <snip>

Quoted message said:

There's been a couple versions of this- a plastic version that
appeared on the Yankee bicycle (I think) and an earlier version (late
70's - early 80's) that was nearly solid steel. Interesting idea- a
truly continuously variable transmission. It worked- but they required
backpedaling to downshift.

Stu clued me in on the earlier version. Here's a copy of a
previous posting:

Quoted message said:

How to Fix your Bicycle by the Technical Publications Division of
Intertec Publishing Corp copyright 1973, no ISBN

Another good tech book, and has some "cutting edge" stuff like a Dana
3 spd planetary system for the crankset(!) as well as a Hagen variable
ratio drive with 6 derailer pulleys sliding in a spiral groove to
change the diameter of the drive (not enough details to tell how it
operates)

My partners at Aerocoupe had one of those Hagen beasties- the entire
crankset probably weighed ten pounds.
The chain rode on six star wheels (with built-in one-way clutches). The
spiral groove moved them into smaller or larger diameters by way of a
brake-like device that stopped the spiral plate from moving while
another plate with tangential grooves continued to drive the star wheels
around. The net effect was that if you stopped the spiral plate while
pedaling forward, your chainring got larger; while if you stopped the
plate and backpedaled, the chainring got smaller. Fascinating device,
but I hate to think what would happen to all those tight-tolerance
grooves once they wore a little.
I don't doubt that Larry Black has one around- probably in its
original box.
Jeff

How was the Hagen on smoothness-it looks as if those corners would give
some psuedo-Biopace irregularities?

Did the wheels index to stop at diameters representative of integer
tooth ring equivalent values or were they completely continuous? If
continuous did the little cogs freewheel spin to adjust for non-integer
link counts (or did you mean something else by one way clutch)?

What were the extreme chainring tooth equivalents, looks like about 24T-
36T if I read the picture right?

--

Bfd said:

"Leo Lichtman" <[email hidden]> wrote in message news:<yv7Ec.40737$OB3.8174@bgtnsc05-
news.ops.worldnet.att.net>...

Quoted message said:

"SDMike" wrote: Geez! Who [censored] in your wheaties this morning?
^^^^^^^^^^^^^ He may be using harsher words than necessary, but he
happens to be right. The things on a bicycle that can be improved are
changing: indexed shifting, increased number and range of ratios,
decreased weight/improved materials, etc. Probably the reason that the
cranks have stayed the same is that they work so well, in spite of
their simplicity. If someone builds a "better mousetrap," the cycling
community will beat a path to his/her door. It is not necessary to
prove that improvements are still possible. They prove themselves.

OK, maybe I have been a bit harsh. So, if the OP wants to redeem
himself, may be he can explain whether either of these 2 cranks work:
http://www.bikedrive.com/english/index.htmhttp://www.bikedrive.com/engl-
ish/index.htm
http://www.powercranks.com/http://www.powercranks.com/ (note - at least
for me, this was a very slow site)

Bikedrive works by letting the crank arm advance relative the rings when
the arm is in high torque positions such as 3:00. In this vicinity the
springs are storing up energy. As one reaches a dead spot and produces
less torque from the crank arms, the springs release their energy
pushing/pulling the rings to catch the arms. Kind of a spring loaded
Biopace system. Says springs at max compression at 3:00, optimal
biopacing would have max compression later-closer to 3:30 or 4:00.

Powercranks are cranks arms that freewheel relative the rings and
independent of each other. It’s a biophysical training tool not a
performance component. The leg muscles in each leg are trained to spin
more effectively because they aren’t relying upon the other leg to
advance it through the leg’s weak spots.

--

A Muzi said:

Francesco Devittori said:

I see racers that strip the paint off their frames to save weight, I
see others that drills holes everywhere (Mayo at Ventoux TT for ex.)
and looking at the crankset I wonder if nobody tried something
different than the traditional design. What about two arms, each with
a small wheel (like the rear der. pulley)? One arm could change its
angle to get a lower/higher gear. No front der (some mechanism to
change that angle would be needed), no chainrings. Plus the chain
won't have to change ring => no risk of falling down.
http://www.frenk.com/silly.pnghttp://www.frenk.com/silly.png (sorry
for the crappy drawing!)

Maybe it's a stupid idea, but I can't believe nobody tried some
alternative solution!

Francesco

Essentially you reinvented the Tokheim Transmission
--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

How effective was the Tokheim Transmission

--