68x10

Tuschinski said:

Fons Moors (First Dutch Marmotte winner) http://users.pandora.be/fons/

Fons is a Fleming.

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

Quoted message said:

There is (was) a Belgian Cyclo-Sportive racer who uses an insane
gearing, *56 11 going up the Alpe D'Huez, Galibier etc.* According to
Fons Moors (First Dutch Marmotte winner) he was actually going pretty
fast with it.

I assume the movies speak for themselves:

http://users.pandora.be/fons/56x11.htm

http://users.pandora.be/fons/filmalbums.htm ->Piet de Bleecker (links
under the pictures)

That guy is still riding, still in the same enormous gear, still in the same
wacky riding position. It also looks as though he's got the same knicks and
jersey on as he had 20 years ago...

I see him most days out training. Sometimes he sits in the bunch with us but
he doesn't usually hang on when the speed gets up. Imagine trying to cover
an attack in that sort of gear. Your joints would collapse!

Jeff

"Jeff Jones" <jeff@cyclingnews-punt-com> wrote in message

Quoted message said:

I see him most days out training. Sometimes he sits in the bunch with us

but

Quoted message said:

he doesn't usually hang on when the speed gets up. Imagine trying to cover
an attack in that sort of gear. Your joints would collapse!

Hey Jeff,

I don't especially to dump off my research onto someone else, but regarding
my comments about Belgian gear restriction elsewhere in the thread, can you
check on it? I recall Davis Phinney remarking that there were gear
restrictions in Belgium, so this would have been around the late 80's. Also,
didn't Belgium also require pros to wear helmets (even if they were strap
helmets) long before the UCI mandated it?

Thanks.

keydates said:

Dumb question:

In the professional ranks, is it possible (albeit, not plausible or
even possible) to chose whatever chainring/cassette you want to ride?
ie, if you wanted to ride a 75x9 (say it does exist, even if it
doesn't), could you? Or is there a limit/restricted gearing?

Ignoring the pointless size of such a gear for anything but salt-flat or HPV
speed record breaking, I think a 10t and 9t would probably suffer too much from
chordal action. I don't think "pico-drives" will ever be seen for this reason
and the associated chain tension and wear issues.

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

Quoted message said:

Ignoring the pointless size of such a gear for anything but salt-flat or

HPV

Quoted message said:

speed record breaking, I think a 10t and 9t would probably suffer too much

from

Quoted message said:

chordal action. I don't think "pico-drives" will ever be seen for this

reason

Quoted message said:

and the associated chain tension and wear issues.

Shimano's Pitch 10 fixed gear drivetrain system was pretty successful,
functionally. The chain pins were only 10 mm apart (10 mm pitch), rather
than the common 1/2 inch, or about 21% smaller. The corresponding chainrings
and sprockets were 21% smaller, too.

SMMB said:

On the Longchamp piste in the Bois de Boulogne is a guy who grinds around
(fast) on a 70x12, almost all the time, mostly en dansant. When he is in
the saddle, it's 70x15, also slow pedal speed. DuraAce with custom
chainring.

This is hard to imagine. A few years ago I built a derney from a mountain
bike frame and wheels with a 71 tooth ring. When I first put it together I
put a 12 fixed cog on. With this gear I was unable to ride up the very
gentle slope of the cul de sac that I live on. In fact, if I put both feet
on one pedal on one side the pedal the crank would lift me up rather than
push the bike forward.

--
Mike Murray

quote='Ewoud Dronkert'On Sat said:

Fons Moors (First Dutch Marmotte winner) http://users.pandora.be/fons/

Fons is a Fleming.[/QUOTE]

You are right. I got it through Hiddema's site and didn't notice he was Belgian (Domain+ language should have told me that). And I am not even sure he was the first belgian to win the Marmotte.

Tuschinski said:

Ewoud Dronkert said:

Tuschinski said:

Fons Moors (First Dutch Marmotte winner)

http://users.pandora.be/fons/

Fons is a Fleming.

Yep, I mistyped🙂

How come my family name comes via descent through Ireland?

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

Quoted message said:

I don't especially to dump off my research onto someone else, but

regarding

Quoted message said:

my comments about Belgian gear restriction elsewhere in the thread, can

you

Quoted message said:

check on it? I recall Davis Phinney remarking that there were gear
restrictions in Belgium, so this would have been around the late 80's.

Also,

Quoted message said:

didn't Belgium also require pros to wear helmets (even if they were strap
helmets) long before the UCI mandated it?

I'll see if any of the retirees I ride with know the answer to that one.
Belgium certainly had compulsory helmet use (in races) a long time before
the UCI made it so.

Jeff

Carl Sundquist said:

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

Quoted message said:

Ignoring the pointless size of such a gear for anything but salt-flat or

HPV

Quoted message said:

speed record breaking, I think a 10t and 9t would probably suffer too much

from

Quoted message said:

chordal action. I don't think "pico-drives" will ever be seen for this

reason

Quoted message said:

and the associated chain tension and wear issues.

Shimano's Pitch 10 fixed gear drivetrain system was pretty successful,
functionally.

I'm not a track rider -- I did not know this. I thought the 10 mm system was
completely dead.

Quoted message said:

The chain pins were only 10 mm apart (10 mm pitch), rather
than the common 1/2 inch, or about 21% smaller. The corresponding chainrings
and sprockets were 21% smaller, too.

I know what you mean. The chordal action aspect is governed by teeth number,
not chain pitch. IOW, a 10 mm pitch 9t cog would suffer just as much from
chordal action as a 1/2 inch pitch 9t cog. The teeth and chain are "discrete"
-- the chain forms "chords" across the circumference of the cog, and too few
chords (low teeth number) can allow the chords to be sensed.

You are correct that the absolute size of the 10 mm system would be smaller for
the same tooth numbers as a "regular" system. However, chain tension would be
higher for the 10 mm system. If the 10 mm system had the everything stepped up
(TK could use a 62x14 instead of a 53x12), then there would be no tension
disadvantage and a chordal action advantage. But that wouldn't be a pico-drive,
in the sense of circumference.

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

Quoted message said:

Carl Sundquist said:

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

Quoted message said:

Ignoring the pointless size of such a gear for anything but salt-flat

or

Quoted message said:

Quoted message said:

HPV

Quoted message said:

speed record breaking, I think a 10t and 9t would probably suffer too

much

Quoted message said:

Quoted message said:

from

Quoted message said:

chordal action. I don't think "pico-drives" will ever be seen for

this

Quoted message said:

Quoted message said:

reason

Quoted message said:

and the associated chain tension and wear issues.

Shimano's Pitch 10 fixed gear drivetrain system was pretty successful,
functionally.

I'm not a track rider -- I did not know this. I thought the 10 mm system

was

Quoted message said:

completely dead.

It is in many ways. Shimano ceased manufacturing it sometime in the late
80's, but some people still swear by it.

Quoted message said:

Quoted message said:

The chain pins were only 10 mm apart (10 mm pitch), rather
than the common 1/2 inch, or about 21% smaller. The corresponding

chainrings

Quoted message said:

Quoted message said:

and sprockets were 21% smaller, too.

I know what you mean. The chordal action aspect is governed by teeth

number,

Quoted message said:

not chain pitch. IOW, a 10 mm pitch 9t cog would suffer just as much from
chordal action as a 1/2 inch pitch 9t cog. The teeth and chain are

"discrete"

Quoted message said:

-- the chain forms "chords" across the circumference of the cog, and too

few

Quoted message said:

chords (low teeth number) can allow the chords to be sensed.

True. As I'm sure you know, that is the reason it is recommended for riders
to use the biggest cog/chainring combination reasonable, up to the point of
increased lateral chain friction on road bikes.

Quoted message said:

You are correct that the absolute size of the 10 mm system would be

smaller for

Quoted message said:

the same tooth numbers as a "regular" system. However, chain tension

would be

Quoted message said:

higher for the 10 mm system. If the 10 mm system had the everything

stepped up

Quoted message said:

(TK could use a 62x14 instead of a 53x12), then there would be no tension
disadvantage and a chordal action advantage. But that wouldn't be a

pico-drive,

Quoted message said:

in the sense of circumference.

Righto.

In article <[email hidden]>,
"Carl Sundquist" <[email hidden]> wrote:

(info on 10mm chain snipped)

There is one thing about this 10mm chain thing that kind of perplexes
me. When you run the smaller gears, there is obviously less chain wrapped
around the circumference, but the chainstays are going to be the same
length for either chain. So the chain with shorter links would need more
links to get from the rings to the rear cog, and with that comes more
overlapping material on the individual links, as well as more pins and
rollers. So it seems like it would end up weighing more than a
conventional chain.

Do track people still use 1/8" wide chains, or have they converted over
to narrower chains? Or is this split down sprinter/kilo riders vs.
pursuiter/ points racer lines (or some variation on that)?

--
tanx,
Howard

I'm Mr. Nice Guy, me.

remove YOUR SHOES to reply, ok?

"Howard Kveck" <[email hidden]> wrote in message >

Quoted message said:

(info on 10mm chain snipped)

There is one thing about this 10mm chain thing that kind of perplexes
me. When you run the smaller gears, there is obviously less chain wrapped
around the circumference, but the chainstays are going to be the same
length for either chain. So the chain with shorter links would need more
links to get from the rings to the rear cog, and with that comes more
overlapping material on the individual links, as well as more pins and
rollers. So it seems like it would end up weighing more than a
conventional chain.

That has been my thought, too. I don't have any weights to compare, though.

Quoted message said:

Do track people still use 1/8" wide chains, or have they converted over
to narrower chains? Or is this split down sprinter/kilo riders vs.
pursuiter/ points racer lines (or some variation on that)?

Pretty much the latter.

Howard Kveck said:

In article <[email hidden]>,
"Carl Sundquist" <[email hidden]> wrote:

(info on 10mm chain snipped)

There is one thing about this 10mm chain thing that kind of perplexes
me. When you run the smaller gears, there is obviously less chain wrapped
around the circumference, but the chainstays are going to be the same
length for either chain. So the chain with shorter links would need more
links to get from the rings to the rear cog, and with that comes more
overlapping material on the individual links, as well as more pins and
rollers. So it seems like it would end up weighing more than a
conventional chain.

Since the plate size would likely be smaller, the overlap is smaller. So too
would be the pins/bushing/sleeve. It might just scale down proportionally for
the most part so that weight is similar, but I don't really know. I don't know
about the pin length. Anyway, 20 g either way isn't going to matter.

In article <[email hidden]>,

gwhite said:

Howard Kveck said:

In article <[email hidden]>,
"Carl Sundquist" <[email hidden]> wrote:

(info on 10mm chain snipped)

There is one thing about this 10mm chain thing that kind of perplexes
me. When you run the smaller gears, there is obviously less chain wrapped
around the circumference, but the chainstays are going to be the same
length for either chain. So the chain with shorter links would need more
links to get from the rings to the rear cog, and with that comes more
overlapping material on the individual links, as well as more pins and
rollers. So it seems like it would end up weighing more than a
conventional chain.

Since the plate size would likely be smaller, the overlap is smaller. So
too would be the pins/bushing/sleeve. It might just scale down
proportionally for the most part so that weight is similar, but I don't
really know. I don't know about the pin length.

I had thought about both of those factors after I posted. And the more I
thought about it, the more:

Quoted message said:

Anyway, 20 g either way isn't going to matter.

made sense to me.

--
tanx,
Howard

"Let's turn dining back into eating."
The Descendents

remove YOUR SHOES to reply, ok?

Quoted message said:

Quoted message said:

rollers. So it seems like it would end up weighing more than a
conventional chain.

The 10mm chain did weigh more and the cog and chainring weighed less with
the total weight being slightly less but not enough to matter.

Other possible benefits were
more cog teeth to give smoother transmission, eg: 48x14 versus 58x17
(roughly the same size when scaled down from 12.7mm to 10mm). This refers
to how the contact point radius on the hub varies as the cog rotates. For a
four tooth cog this would change by the square root of two, or more then
40%. For a 14 and 17 tooth cog that ratio would be 2.5% and 1.7%. The
formula for the radius is cos(180/teeth) = 0.9749 and 0.9829.

less air resistance due to smaller size,

My recollection of the history of the 10mm system was that it was growing in
popularity until it was outlawed in Japan kerin racing.

Bruce

Bruce Frech said:

Quoted message said:

Quoted message said:

rollers. So it seems like it would end up weighing more than a
conventional chain.

The 10mm chain did weigh more and the cog and chainring weighed less with
the total weight being slightly less but not enough to matter.

Other possible benefits were
more cog teeth to give smoother transmission, eg: 48x14 versus 58x17
(roughly the same size when scaled down from 12.7mm to 10mm). This refers
to how the contact point radius on the hub varies as the cog rotates. For a
four tooth cog this would change by the square root of two, or more then
40%. For a 14 and 17 tooth cog that ratio would be 2.5% and 1.7%. The
formula for the radius is cos(180/teeth) = 0.9749 and 0.9829.

With chains, weight is a small factor relative to transmission efficieny. A 20% reduction
in a chain corresponds roughly to a 0.15% reduction in total mass, yielding no more
than a 0.15% change in speed at a given input power (and that's only in the extreme case
of a steep hill or rolling-resistance-limited riding). On the other hand, a 20% reduction
in transmission losses in a system which is maybe 95% effective yields a 1% increase
in useful power -- an effect at least 7 times greater.

Dan

"Dan Connelly" <d_j_c_o_n_n_e_l@i_e_e_e.o_r_g> wrote in message
news:[email hidden]...

Quoted message said:

Bruce Frech said:

Quoted message said:

>rollers. So it seems like it would end up weighing more than a
>conventional chain.

The 10mm chain did weigh more and the cog and chainring weighed less

with

Quoted message said:

Quoted message said:

the total weight being slightly less but not enough to matter.

Other possible benefits were
more cog teeth to give smoother transmission, eg: 48x14 versus 58x17
(roughly the same size when scaled down from 12.7mm to 10mm). This

refers

Quoted message said:

Quoted message said:

to how the contact point radius on the hub varies as the cog rotates.

For a

Quoted message said:

Quoted message said:

four tooth cog this would change by the square root of two, or more then
40%. For a 14 and 17 tooth cog that ratio would be 2.5% and 1.7%. The
formula for the radius is cos(180/teeth) = 0.9749 and 0.9829.

With chains, weight is a small factor relative to transmission efficieny.

A 20% reduction

Quoted message said:

in a chain corresponds roughly to a 0.15% reduction in total mass,

yielding no more

Quoted message said:

than a 0.15% change in speed at a given input power (and that's only in

the extreme case

Quoted message said:

of a steep hill or rolling-resistance-limited riding). On the other

hand, a 20% reduction

Quoted message said:

in transmission losses in a system which is maybe 95% effective yields a

1% increase

Quoted message said:

in useful power -- an effect at least 7 times greater.

Dan

Dan,

I wasn't talking about weight or mass. The 2.5% versus 1.7% refers to the
fluctuation in speed of the wheel, assuming a constant speed of the pedals
and no other absorbtion of flucuation in the drivetrain. So if the chain
has a constant speed then the wheel rotation varies with the radius of the
contact point. I know it doesn't actually happen that way, but that is what
the computation was refering to. Most likely the chain tension varies
slightly as well as the strain shown by all the other moving parts between
the pedals and the rubber on the road.

Now if more teeth on the cog give a smoother ride then that would be a
desireable feature. Does anyone notice the difference in smoothness
between, for example, a 42-12 and a 53-15?

Bruce

Bruce Frech said:

Quoted message said:

Other possible benefits were
more cog teeth to give smoother transmission, eg: 48x14 versus 58x17
(roughly the same size when scaled down from 12.7mm to 10mm). This refers
to how the contact point radius on the hub varies as the cog rotates.

In truth, I don't so much sense chordal action on a road bike because road
roughness can swamp the perception out due to the road "roughnesses" much higher
magnitude. I do sense it on smooth roads and the 12t cog, although I don't much
use that one much anymore.

I hadn't thought about it (since I don't ride track), but since tracks are
probably much smoother, it is more likely to be sensed by track riders. I
think Carl implied he was able to sense it, but I'll let him clarify if he
wishes (or any of the other track contributers). Basically one would hope to
have enough teeth such that the discretization/quantization was not detectable.

Quoted message said:

My recollection of the history of the 10mm system was that it was growing in
popularity until it was outlawed in Japan kerin racing.

The Shimano cranks also required a [censored] pedal axle diameter too, again IIRC.

I think the following closely aligns with the numbers you gave:

2.4 CHORDAL ACTION
Another major problem with roller chain drives is the variation in speed or
surging caused by the acceleration and
deceleration of the chain as it goes around the sprocket link by link. This
variation of speed is called "Chordal
Action" or "Pitch Line Rise and Fall". It starts as soon as the pitch line of
the chain contacts the first tooth of the
sprocket. This contact occurs at a point below the pitch circle of the sprocket.
As the sprocket rotates, the chain
is raised up to the pitch circle and is then dropped down again as sprocket
rotation continues. Because of the fixed
pitch length, the pitch line of the link cuts across the chord between two pitch
points on the sprocket, remaining in
this position relative to the sprocket until the link exits the sprocket. This
rising and falling of the pitch line is what
causes chordal effect or speed variation.
Chordal action is inversely proportionate to the number of teeth on the
sprocket. Drive configurations which have
25 or more teeth on the sprocket exhibit minimal chordal action - about 1/2 of
1% in the variation of the speed of
the chain. However, as the number of teeth in the sprocket decline, the
variation in the chain speed increases
dramatically.
Using a 17 tooth sprocket, the speed variation is about 1.5%. A 10 tooth
sprocket produces a variation of about
5%. This pitch line rising and falling which results in speed variation at low
speed, will produce vibration as the
chain speed is increased. To further compound the problem, this chordal effect
will be transmitted through the
entire drive system, affecting the chain, the sprockets and bearings and seals,
as well as the driven component. A
perfect example is the concern for roll grinders.
http://www.gates.com/facts/documents/Gf000379.pdf

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3. Sprockets – Small Sprocket Size

What is the smallest suggested sprocket sizes to minimize the effects of chordal
action?

ANSWER: The smallest sprocket is usually the driver or input sprocket. As the
chain enters and exits, it rises and falls as each pitch engages and disengages
the sprockets. This movement, called chordal action, causes chain-speed
variations (drive roughness) that may be objectionable in some applications.
These variations can normally be minimized by increasing the size of the
sprockets. To minimize the negative effects of chordal action, the following are
suggested guidelines for the minimum number of teeth in the smallest sprockets:
Slow speed drive (Drip type lubrication) – 12 teeth, Medium speed drive (Oil
bath type lubrication) – 17 teeth, and High speed drive (Pumped lubrication)
http://www.diamondchain.com/techfaqs.asp

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All about chains:
http://www.drivesinc.com/attach-PDFs/attach-glossry.pdf

g

Yes chordal action is what I was describing, and the numbers agree.

The different size pedal axle was a different year. It was the AX road
system, with 1" threads with the bearings inside the crank region allowing
the pedal to be below the center of the axle. This was a good goal from the
biomechanical point of view but the bearings just didn't work mechanically.

Bruce

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

Quoted message said:

Bruce Frech said:

Quoted message said:

Other possible benefits were
more cog teeth to give smoother transmission, eg: 48x14 versus 58x17
(roughly the same size when scaled down from 12.7mm to 10mm). This

refers

Quoted message said:

Quoted message said:

to how the contact point radius on the hub varies as the cog rotates.

In truth, I don't so much sense chordal action on a road bike because road
roughness can swamp the perception out due to the road "roughnesses" much

higher

Quoted message said:

magnitude. I do sense it on smooth roads and the 12t cog, although I

don't much

Quoted message said:

use that one much anymore.

I hadn't thought about it (since I don't ride track), but since tracks are
probably much smoother, it is more likely to be sensed by track riders.

I

Quoted message said:

think Carl implied he was able to sense it, but I'll let him clarify if he
wishes (or any of the other track contributers). Basically one would hope

to

Quoted message said:

have enough teeth such that the discretization/quantization was not

detectable.

Quoted message said:

Quoted message said:

My recollection of the history of the 10mm system was that it was

growing in

Quoted message said:

Quoted message said:

popularity until it was outlawed in Japan kerin racing.

The Shimano cranks also required a [censored] pedal axle diameter too, again

IIRC.

Quoted message said:

The different size pedal axle was a different year. It was the AX road
system, with 1" threads with the bearings inside the crank region allowing
the pedal to be below the center of the axle. This was a good goal from the
biomechanical point of view but the bearings just didn't work mechanically.

Quoted message said:

I think the following closely aligns with the numbers you gave:

Yes chordal action is what I was describing, and the numbers agree.

Quoted message said:

2.4 CHORDAL ACTION
Another major problem with roller chain drives is the variation in speed

or

Quoted message said:

surging caused by the acceleration and
deceleration of the chain as it goes around the sprocket link by link.

This

Quoted message said:

variation of speed is called "Chordal
Action" or "Pitch Line Rise and Fall". It starts as soon as the pitch line

of

Quoted message said:

the chain contacts the first tooth of the
sprocket. This contact occurs at a point below the pitch circle of the

sprocket.

Quoted message said:

As the sprocket rotates, the chain
is raised up to the pitch circle and is then dropped down again as

sprocket

Quoted message said:

rotation continues. Because of the fixed
pitch length, the pitch line of the link cuts across the chord between two

pitch

Quoted message said:

points on the sprocket, remaining in
this position relative to the sprocket until the link exits the sprocket.

This

Quoted message said:

rising and falling of the pitch line is what
causes chordal effect or speed variation.
Chordal action is inversely proportionate to the number of teeth on the
sprocket. Drive configurations which have
25 or more teeth on the sprocket exhibit minimal chordal action - about

1/2 of

Quoted message said:

1% in the variation of the speed of
the chain. However, as the number of teeth in the sprocket decline, the
variation in the chain speed increases
dramatically.
Using a 17 tooth sprocket, the speed variation is about 1.5%. A 10 tooth
sprocket produces a variation of about
5%. This pitch line rising and falling which results in speed variation at

low

Quoted message said:

speed, will produce vibration as the
chain speed is increased. To further compound the problem, this chordal

effect

Quoted message said:

will be transmitted through the
entire drive system, affecting the chain, the sprockets and bearings and

seals,

Quoted message said:

as well as the driven component. A
perfect example is the concern for roll grinders.
http://www.gates.com/facts/documents/Gf000379.pdf

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3. Sprockets - Small Sprocket Size

What is the smallest suggested sprocket sizes to minimize the effects of

chordal

Quoted message said:

action?

ANSWER: The smallest sprocket is usually the driver or input sprocket. As

the

Quoted message said:

chain enters and exits, it rises and falls as each pitch engages and

disengages

Quoted message said:

the sprockets. This movement, called chordal action, causes chain-speed
variations (drive roughness) that may be objectionable in some

applications.

Quoted message said:

These variations can normally be minimized by increasing the size of the
sprockets. To minimize the negative effects of chordal action, the

following are

Quoted message said:

suggested guidelines for the minimum number of teeth in the smallest

sprockets:

Quoted message said:

Slow speed drive (Drip type lubrication) - 12 teeth, Medium speed drive

(Oil

Quoted message said:

bath type lubrication) - 17 teeth, and High speed drive (Pumped

lubrication)

Quoted message said:

http://www.diamondchain.com/techfaqs.asp

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All about chains:
http://www.drivesinc.com/attach-PDFs/attach-glossry.pdf