Three arm cranksets

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In article ,
Retro Bob wrote:

In days of old, there were a fair number of 3 arm cranksets around.
I've made a WAG that the change to 5 arm cranks was due to flex
in the 3 arm when pushing hard. I know I can even distort a 5 if I
push out a little rather than straight ahead on the cranks when
pumping hard.

Have I called this right ? Were the 3 arm cranks really poor in this
respect ? Should you (me) avoid them when building a "vintage"
machine ?

_ Those 3 arm cranksets were bomber, they were generally made of
steel. The only reason to avoid them is the weight penalty and
the difficultly of finding spare chainring sets.

_ Booker C. Bense


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On Tue, 28 Sep 2004 20:43:47 GMT, Retro Bob
wrote:


In days of old, there were a fair number of 3 arm cranksets around.
I've made a WAG that the change to 5 arm cranks was due to flex
in the 3 arm when pushing hard. I know I can even distort a 5 if I
push out a little rather than straight ahead on the cranks when
pumping hard.

Have I called this right ? Were the 3 arm cranks really poor in this
respect ? Should you (me) avoid them when building a "vintage"
machine ?

Can you say "cast iron"? They weren't weak, they just weighed more
than a modern frame..and BB, and cranks, and ders...put together.

If you can find rings for them and they're in good shape, there's no
significant reason to avoid using them.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Retro Bob wrote:

In days of old, there were a fair number of 3 arm cranksets around.
I've made a WAG that the change to 5 arm cranks was due to flex
in the 3 arm when pushing hard. I know I can even distort a 5 if I
push out a little rather than straight ahead on the cranks when
pumping hard.

Have I called this right ? Were the 3 arm cranks really poor in this
respect ? Should you (me) avoid them when building a "vintage"
machine ?

Splitting hairs. We humans don't usually flex any cranks
enough to notice.

There's no functional difference, the standard 3-pin format
went to 36t and there were plenty of vendors at one time.

Over the years, though, five at 144, 135, 130 and 110mm
became the more popular dimensions.

(The 6-pin format of TA, Sugino Dynamic and Cyclo also
drifted away)

If you own a nice 3-pin crank, as I do, ride it. If you're
buying a new crank, get one of the mentioned five-pin
cranks (but not a 144 unless it's a single ring).

Personally I'd ride a nice mid-seventies Campagnolo 3-pin
steel square taper chromed crank in a minute if I had one (
I do own rings for that already). It would look nice with
my Cinelli #1 steel chromed stem and a Svelto or a chromed
bronze Record changer. Oh, and a pair of shiny 1037 would
look sharp in them as well!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Tue, 28 Sep 2004 20:43:47 +0000, Retro Bob wrote:


In days of old, there were a fair number of 3 arm cranksets around. I've
made a WAG that the change to 5 arm cranks was due to flex in the 3 arm
when pushing hard.

Nah. Fashion. Campy went that way and everyone else followed. 3-arm
cranks were patterned after older, steel cranks like Magistroni. Can be
better looking, but not fashionable.

--

David L. Johnson

__o | "It doesn't get any easier, you just go faster." --Greg LeMond
_`\(,_ |
(_)/ (_) |

On Tue, 28 Sep 2004 23:20:42 +0000, Retro Bob wrote:

I'm not considering the steel ones, but there are some vintage early
designs alloy by Stronglight, TA, and even Campy.

Campy? I never saw one of those. Do you have a link to a picture?

--

David L. Johnson

__o | Become MicroSoft-free forever. Ask me how.
_`\(,_ |
(_)/ (_) |

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In article ,
Retro Bob wrote:
On Wed, 29 Sep 2004 11:09:05 -0400, "David L. Johnson"
wrote:

Campy? I never saw one of those. Do you have a link to a picture?


http://www.classicrendezvous.com/Ita...mpy_cranks.htm

_ That one looks like alloy, but the one that I own is definitely
steel.

_ Booker C. Bense

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In article ,
Retro Bob wrote:
On Wed, 29 Sep 2004 11:09:05 -0400, "David L. Johnson"
wrote:

Campy? I never saw one of those. Do you have a link to a picture?


http://www.classicrendezvous.com/Ita...mpy_cranks.htm

_ That one looks like alloy, but the one that I own is definitely
steel.

_ Booker C. Bense

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On Wed, 29 Sep 2004 18:32:06 +0000, Booker C. Bense wrote:


Campy? I never saw one of those. Do you have a link to a picture?


http://www.classicrendezvous.com/Ita...mpy_cranks.htm

_ That one looks like alloy, but the one that I own is definitely steel.

We are getting progressively more esoteric here, but do you mean steel,
three-arm, Campy cranks? I was surprised enough to see the alloy one
above -- never seen one in the flesh.

Lots of 3-arm steel cranks around. I used to have a Magestroni, but there
were several brands. Most probably being used as boat anchors now.

--

David L. Johnson

__o | "It doesn't get any easier, you just go faster." --Greg LeMond
_`\(,_ |
(_)/ (_) |

On Wed, 29 Sep 2004 18:32:06 +0000, Booker C. Bense wrote:


Campy? I never saw one of those. Do you have a link to a picture?


http://www.classicrendezvous.com/Ita...mpy_cranks.htm

_ That one looks like alloy, but the one that I own is definitely steel.

We are getting progressively more esoteric here, but do you mean steel,
three-arm, Campy cranks? I was surprised enough to see the alloy one
above -- never seen one in the flesh.

Lots of 3-arm steel cranks around. I used to have a Magestroni, but there
were several brands. Most probably being used as boat anchors now.

--

David L. Johnson

__o | "It doesn't get any easier, you just go faster." --Greg LeMond
_`\(,_ |
(_)/ (_) |

On Wed, 29 Sep 2004 17:30:02 GMT, Retro Bob
wrote:

On Wed, 29 Sep 2004 11:09:05 -0400, "David L. Johnson"
wrote:

Campy? I never saw one of those. Do you have a link to a picture?


http://www.classicrendezvous.com/Ita...mpy_cranks.htm

That crank set is a beautiful piece of art! Why does the chain ring
tooth profile look so much deeper than for example the teeth on a
Shimano 105 crank set? Does the deep tooth profile increase friction
as the chain engages and disengages the chain ring? My old steel
chain rings have about 30,000 miles on them and I was thinking of
upgrading to a newer crank set. I'm not sure about how long a new
crank set would last or if it would effect chain wear.