Funny Chain Lubricant Story

An online magazine ran an article on dry lubricants. They lubed a chain and
then allowed it to swing back and forth and measured the friction on it.
After 10 minutes or so the friction would start picking up and then within a
half hour the chain would be essentially unlubricated.

I asked what happened if they tested motor oil. The comment was that it
require weeks for the chain to start getting increased friction so they
didn't want to run such tests.

What does that tell you?

On Jun 12, 4:43*pm, "Tom Kunich" cyclintom@yahoo. com wrote:
An online magazine ran an article on dry lubricants. They lubed a chain and
then allowed it to swing back and forth and measured the friction on it.
After 10 minutes or so the friction would start picking up and then within a
half hour the chain would be essentially unlubricated.

I asked what happened if they tested motor oil. The comment was that it
require weeks for the chain to start getting increased friction so they
didn't want to run such tests.

What does that tell you?

that you can't compare apples to oranges, that an engine has a
enclosed drivetrain and a bike has an exposed drivetrain; the dry lube
is to help prevent accumulation of gunk; further, the chaindrive is
something like 99% efficient, so you can basically do whatever you
like- the difference is how messy do you really want to get ?

On Thu, 12 Jun 2008 13:43:15 -0700, "Tom Kunich" cyclintom@yahoo.
com wrote:

An online magazine ran an article on dry lubricants. They lubed a chain and
then allowed it to swing back and forth and measured the friction on it.
After 10 minutes or so the friction would start picking up and then within a
half hour the chain would be essentially unlubricated.

I asked what happened if they tested motor oil. The comment was that it
require weeks for the chain to start getting increased friction so they
didn't want to run such tests.

What does that tell you?

Dear Tom,

It may tell us that the online magazine mis-measured friction.

Spicer tested lubricated and unlubricated bicycle chains in 2000 and
found that lubrication had no significant effect on transmission
efficiency--even when the lubricant was removed by cleaning.

After testing a chain with Castrol Wrench Force Dry Lube, Pedro’s Syn
Lube, Generation 4 White Lightning, Spicer thoroughly cleaned the
chain and tested it dry.

No significant differences were noted by his testing equipment:

"However, these results also indicate that the actual lubricant used
has little effect on the overall performance of the drive under
laboratory conditions given the precision of the measurement.
In addition, the chain used for the lubrication study was fully
degreased and was re-tested for efficiency. This degreasing operation
consisted of a five-minute scrub with kerosene followed by a cleaning
with Castrol Degreaser. The measured efficiency of the de-lubricated
chain for the 52–15 combination at 60 RPM and 100 W was 90.3% and at
200 W was 96.5%. These efficiencies are essentially the same as those
measured for the chain in the re-lubricated condition."

It's the first article he
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

Cheers,

Carl Fogel

wrote in message
...

Spicer tested lubricated and unlubricated bicycle chains in 2000 and
found that lubrication had no significant effect on transmission
efficiency--even when the lubricant was removed by cleaning.

After testing a chain with Castrol Wrench Force Dry Lube, Pedro's Syn
Lube, Generation 4 White Lightning, Spicer thoroughly cleaned the
chain and tested it dry.

No significant differences were noted by his testing equipment:
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

That's pretty interesting. You do understand that the idea of testing a
CLEAN chain isn't of much use? Or that lubrication is supposed to allow the
chain to run low friction despite dirt etc. in the mechanism?

On Thu, 12 Jun 2008 15:16:05 -0700, "Tom Kunich" cyclintom@yahoo.
com wrote:

wrote in message
.. .

Spicer tested lubricated and unlubricated bicycle chains in 2000 and
found that lubrication had no significant effect on transmission
efficiency--even when the lubricant was removed by cleaning.

After testing a chain with Castrol Wrench Force Dry Lube, Pedro's Syn
Lube, Generation 4 White Lightning, Spicer thoroughly cleaned the
chain and tested it dry.

No significant differences were noted by his testing equipment:
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

That's pretty interesting. You do understand that the idea of testing a
CLEAN chain isn't of much use? Or that lubrication is supposed to allow the
chain to run low friction despite dirt etc. in the mechanism?

Dear Tom,

As Spicer's testing showed, lubrication has next to no effect on
bicycle chain transmission efficiency.

The chief effect of lubrication on bicycle chains is to keep grit out.

Anyone can read Spicer's test:
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

Maybe you can tell us more about whatever test you had in mind.

Cheers,

Carl Fogel

On Jun 12, 6:34 pm, wrote:


The chief effect of lubrication on bicycle chains is to keep grit out.

I'd have said the chief effect of lubrication is to trap the grit on
the chain, and distribute it on other parts of the bike. And the
rider's leg.

That's been true of every wet lube I've tried, anyway.

- Frank Krygowski

On Thu, 12 Jun 2008 21:21:27 -0700 (PDT), Frank Krygowski
wrote:

On Jun 12, 6:34 pm, wrote:


The chief effect of lubrication on bicycle chains is to keep grit out.

I'd have said the chief effect of lubrication is to trap the grit on
the chain, and distribute it on other parts of the bike. And the
rider's leg.

That's been true of every wet lube I've tried, anyway.

- Frank Krygowski

Dear Frank,

Wet lube initially keeps road dust out. (Nothing larger will fit
between pins and rollers.)

Any wet lube traps the road dust flung up by the tires, so the wet
lube turns black within a few miles.

After that, the outside of the chain is covered with an extremely fine
polishing sludge, which gradually mixes with the thin film of clean
lube inside the rollers as the minuscule pumping action draws it in
and out.

Eventually, the area between the pins and rollers builds up a thin
layer of polishing paste.

Chain wear rates suggest how long the process takes.

Each roller turns a tiny bit as it engages the top of the front
sprocket, a tiny bit as it exits, and ditto for the rear sprocket and
any idler pulleys.

But only two of the turns are under any significant load, when the
chain is pulled onto the front sprocket and pulls off the rear
sprocket.

At 100 rpm on a 53-tooth front sprocket, the chain moves at a mere 2.5
mph. (At the same 100 rpm on a 175 mm crank, the rider's foot whirls
at a blistering 4.1 mph.)

At 100 rpm on a 53-tooth sprocket, an individual roller on a
106-roller chain makes its small partial turn under load (entering the
front or leaving the rear sprocket) at only a rate of once every
3/5ths of a second.

How small is that turn?

As it pulls onto the front 53-tooth, the roller turns and locks in
1/53rd of a circle--a bit less than 7 degrees. (About 9 degrees for a
39-tooth.) Then it just sits there until it eases off the sprocket.

The extreme case is an 11-tooth rear, where the chain pulling off has
its pin and roller turn about 32 degrees.

So an hour of 100 rpm riding produces only 6,000 partial polishing
rotations (7 to 32 degrees) on any single pin and roller, amounting to
much less than 400 full turns per hour.

That's about 0.25 rpm.

(The 106-roller chain is a convenient figure that's easy to calculate
and produces a slightly inflated result compared to the typical
~114-roller chain.)

In other words, most bicycle chains last over a thousand miles, even
on a diet of polishing paste made from oil and road dust, because the
individual pins and rollers turn so little and because the polishing
paste can contain only the grains of extremely hard road dust small
enough to fit between the pins and rollers, whose clearance is below
what a typical micrometer can measure.

As a crude example, a 53x19 at 91.5 rpm on a 2124 mm tires is doing 20
mph. Each pin on a 106-roller chain makes its partial turns under load
at 91.5 rpm, about 5500 partial polishing turns every hour or every 20
miles. That's 27,500 slight "grinds" averaging only about 20 degrees
in a thousand miles and fifty hours of steady riding at about 90 rpm.

When 25 of these pins (the ends of a foot-long ruler) wear 0.0025",
the chain elongates a full 1/16th of an inch (0.0625") and should be
replaced. The 0.0025" wear on each pin-roller combination amounts to
about the thickness of a sheet of flimsy phone-book paper.

***

Such incredibly tiny wear explains why it's almost impossible to clean
real wet-lube chains that have gotten dirty.

Dunk a dirty, oily chain in solvent in an ultrasonic cleaner, shake it
in a bottle, do whatever you please--

Eventually, you'll probably run out of patience before fresh solvent
stops producing wisps of filth from what looks like an immaculate
chain.

The solvent acts only on the incredibly thin exposed edge of the film
of oil-and-grime trapped between each pin and roller, a surface that
isn't much wider than a human hair. Given such poor access, the
solvent takes forever, even with shaking or ultrasonic action, to eat
into the mess trapped between the pins and rollers.

***

Dry wax has the advantage that it draws no road dust into the
pin-roller interface. Instead of a oily film pumping in and out, the
dry lube flakes outward under pressure from between the pin and roller
and never returns.

The price for this is that the dry lube needs to be re-applied more
often than a wet lube (with exceptions of all kinds for different
lubes and conditions).

Frank is quite happy with wax that has some oil added, others swear by
various oils, and I've been reasonably pleased with Dupont Teflon
spray wax.

(I can't recommend it over oil or melted wax, but it's fairly cheap,
easy to apply, and has a pleasant new-toy effect that hasn't worn off
yet.)

***

As far as I know, lubrication makes no significant difference to chain
friction in terms of power transmission. Spicer's article explains the
theory behind this unexpected result, which could be grossly
simplified to a matter of how little actual polishing action takes
place in the lazily moving chain of a bicycle.

Even a dry chain that squeaks like a box full of bats still transmits
almost exactly the same power as a brand-new factory-lubed chain--the
noise is annoying, but it's apparently all out of proportion to the
increase in friction.

Cheers,

Carl Fogel

On 2008-06-13, wrote:
[...]
Each roller turns a tiny bit as it engages the top of the front
sprocket, a tiny bit as it exits, and ditto for the rear sprocket and
any idler pulleys.

But only two of the turns are under any significant load, when the
chain is pulled onto the front sprocket and pulls off the rear
sprocket.

At 100 rpm on a 53-tooth front sprocket, the chain moves at a mere 2.5
mph. (At the same 100 rpm on a 175 mm crank, the rider's foot whirls
at a blistering 4.1 mph.)

At 100 rpm on a 53-tooth sprocket, an individual roller on a
106-roller chain makes its small partial turn under load (entering the
front or leaving the rear sprocket) at only a rate of once every
3/5ths of a second.

How small is that turn?

As it pulls onto the front 53-tooth, the roller turns and locks in
1/53rd of a circle--a bit less than 7 degrees. (About 9 degrees for a
39-tooth.) Then it just sits there until it eases off the sprocket.

The extreme case is an 11-tooth rear, where the chain pulling off has
its pin and roller turn about 32 degrees.

So an hour of 100 rpm riding produces only 6,000 partial polishing
rotations (7 to 32 degrees) on any single pin and roller, amounting to
much less than 400 full turns per hour.

That's about 0.25 rpm.

It is said that cross-chaining increases rate of wear. Why is that? Are
the pins still only worn as they pull on and off the front and rear
sprockets, and it's made worse by having to pull them back into line, or
do they get worn continuously in some way in a cross-chaining situation?

On Jun 13, 3:50 am, Ben C wrote:


It is said that cross-chaining increases rate of wear. Why is that? Are
the pins still only worn as they pull on and off the front and rear
sprockets, and it's made worse by having to pull them back into line, or
do they get worn continuously in some way in a cross-chaining situation?

My guess would be this: With the chain running at an angle, the loads
transmitted between links and pins (at the same parts of the chain
travel Carl describes) are not supported by the entire width of the
pin. They're supported by a larger pressure load applied to the end
of the pin, while the rest of the pin gives little help. More
pressure leads to more wear. Similar problems exist when mechanical
shafts are supported by plain bearings that are not in proper
alignment; and for shafts that are insufficiently rigid, and deflect
under load as they spin. All this stuff works better when things are
straight.

In addition, IIRC, chain efficiency is lower when the chain doesn't
run in a straight line. I imagine this is partly due to the effect I
just described, and partly because a laterally-bent chain generates
more friction between the side plates.

- Frank Krygowski

Frank Krygowski wrote:

It is said that cross-chaining increases rate of wear. Why is
that? Are the pins still only worn as they pull on and off the
front and rear sprockets, and it's made worse by having to pull
them back into line, or do they get worn continuously in some way
in a cross-chaining situation?

My guess would be this: With the chain running at an angle, the
loads transmitted between links and pins (at the same parts of the
chain travel Carl describes) are not supported by the entire width
of the pin. They're supported by a larger pressure load applied to
the end of the pin, while the rest of the pin gives little help.
More pressure leads to more wear. Similar problems exist when
mechanical shafts are supported by plain bearings that are not in
proper alignment; and for shafts that are insufficiently rigid, and
deflect under load as they spin. All this stuff works better when
things are straight.

In addition, IIRC, chain efficiency is lower when the chain doesn't
run in a straight line. I imagine this is partly due to the effect
I just described, and partly because a laterally-bent chain
generates more friction between the side plates.

Effects of running chains diagonally, between sprockets not on the
same line, is apparent from worn chain pictures on the web that show a
worn link pins that have barrel shaped wear grooves at mid section.
The depth of the wear groove at its ends indicating canted loading.

Even with more closely spaced (10) sprockets, a greater angle occurs
than was common with five slightly wider spaced sprocket. In the days
of 5-sprocket clusters riders generally used the inner chainwheel to
drive the lower three and the large chainwheel to drive the upper
three, seldom riding in extreme cross-over mode. It was once a topic
of discussion on this newsgroup, but now that 30 combinations are
possible, little consideration is given to resulting chain life,
constant cadence having higher priority regardless of what chain line
this requires.

Jobst Brandt