Why no sapphire / diamond chainwheels, cogs, or chains?

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

No, people would wear them much more often. Especially to parties.
--
Rick Onanian

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>

Quoted message said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond?

You could try to find a carbon chainwheel, and ride it *really*
hard...

--
jc

Remove the -not from email

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

Actually, anodized aluminum is 7x harder than regular unanodized
aluminum, so a thick layer of aluminum oxide is serving the same
purpose as these other hard coatings that you are asking about.

- Don Gillies
San Diego, CA

"none" wrote🙁clip)sapphire or diamond? Wouldn't this help to decrease wear
on these components?
^^^^^^^^^^^^^^^
How old are you? Does your background include Hi-fi and vinyl records?

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

-Mike

Er, economics? It's cheaper to keep replacing drivetrain components
than to make them last longer. On the other hand, TiN (Titanium
Nitride) coating is not too expensive, especially on a titanium
substrate, so it's slightly surprising that Ti sprockets as seen on
Record and DuraAce cassettes aren't that nice shiny gold colour.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

none <[email hidden]> wrote in message news:<ZLMSc.6682$BS3.6018@trndny04>...

Quoted message said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

-Mike

Some industrial equipment is already made with a diamond-like carbon
coating on the wear surfaces, as an alternative to carburised or
nitrided case-hardening. For example, some air compressors supplying
oil-free air use this technology.

Possibly some applications of chain drive might (or one day will) use
chains hardened like this. But I doubt that it will catch on for
bicycles designed to be status symbols. There is no point in
equipping a bicycle with high tech gear that is not immediately
recognisable as expensive. Hmmm ... unless ... is there some way of
making the chain brightly coloured?

Jeremy Collins said:

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond?

You could try to find a carbon chainwheel, and ride it *really*
hard...

http://www.fibre-lyte.co.uk/

"CARBON FIBRE CHAIN RINGS

The properties of carbon fibre are ideal for track, time trial and
triathlon machines, there is no lighter chain ring available -
remember carbon fibre is half the weight of aluminium. We advise that
these chainrings are used only in a single ring set up. When used in a
multi ring set up these rings can be damaged by hard and aggressive
front gear changing, however, customers have had 1000's miles with
careful changing or as a single ring set up."

etc.

Would be nice to try a set!

dianne_1234 said:

...
The properties of carbon fibre are ideal for track, time trial and
triathlon machines, there is no lighter chain ring available -
remember carbon fibre is half the weight of aluminium....

They should find an advertising copywriter who knows the difference
between weight and density.

--
Tom Sherman – Quad City Area

Tom Sherman said:

dianne_1234 said:

...
The properties of carbon fibre are ideal for track, time trial and
triathlon machines, there is no lighter chain ring available -
remember carbon fibre is half the weight of aluminium....

They should find an advertising copywriter who knows the difference
between weight and density.

I think they're relying on potential customers who don't.

Mark McMaster
[email hidden]

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

Brittle; unless polished to a glass-like edgeless finish, abrasive;
non-self-lubricating in any event...

A chain coated with those materials would eat the sprocket; remember;
it's going to have edges even if the coating is evenly applied and
highly polished. Likewise, a sprocket coated with them would eat the
chain. If both were so treated, it would be a race to see which ate
the coating from the other first, after which the destruction would be
one-sided.

This completely ignores the likely cost, and the fact that in order to
apply such a coating, you'd have to come up with a truly exotic alloy
for the metal parts to allow them to retain their strength through the
long and intense heating required to deposit the material.

There is a completely different high-durability low-friction coating
process that theoretically might be applicable, but it might make the
Wippermann 10-speed chain seem cheap by comparison.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Quoted message said:

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>

Quoted message said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

none said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

if it's the right kind of coating, yes it would. but the best method of
decreasing wear is to just lube the chain.

also, note that sapphire is essentially aluminum oxide. so is the
anodizing coat that's applied. not all anodizing is there for wear
resistance, but, it's well known in that application.

diamond coatings do exist, as do a whole host of others including
titanium carbide & titanium nitride. they impart excellent wear resistance.

jim beam said:

depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Quoted message said:

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>

Quoted message said:

Why aren't there any bicycle chainwheels or chain side plates / rivets
coated with sapphire or diamond? Wouldn't this help to decrease wear on
these components?

-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

Dear Jim,

So it looks as if at a fine enough level I'm wrong again.

Sigh.

Carl Fogel

Quoted message said:

jim beam said:

depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Quoted message said:

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>
wrote:

>Why aren't there any bicycle chainwheels or chain side plates / rivets
>coated with sapphire or diamond? Wouldn't this help to decrease wear on
>these components?
>
>-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

Dear Jim,

So it looks as if at a fine enough level I'm wrong again.

Sigh.

Carl Fogel

not "wrong", just learning.

Dura Ace 9s chains have incredibly hard surface on the pins which places all of the measurable wear (in my experience) on the flanged side plates.

Looking under magnification at the older style pins (not center peened like current), one could see this surface was cracked. Since the cracks extended only to the riveted plate interface, wear was not compromised but these cracks could promote corrosion. The current peening method used shows none of this cracking.

I have only been able to "scratch" this surface with a diamond and silicon carbide. Aluminum oxide does nothing to it but polish its surface. Even hard carbide just slides over the surface.

Quoted message said:

jim beam said:

depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Quoted message said:

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>
wrote:

>Why aren't there any bicycle chainwheels or chain side plates / rivets
>coated with sapphire or diamond? Wouldn't this help to decrease wear on
>these components?
>
>-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

Dear Jim,

So it looks as if at a fine enough level I'm wrong again.

I dunno, if you make the diamond fine enough you get graphite a pretty decent
lubricant. Well yeah, that's at the molecular level, but you did say "really
fine" didn't you.

Ron

quote='RonSonic'On Sun said:

jim beam said:

depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Quoted message said:

On Thu, 12 Aug 2004 16:19:05 GMT, none <[email hidden]>
wrote:

>Why aren't there any bicycle chainwheels or chain side plates / rivets
>coated with sapphire or diamond? Wouldn't this help to decrease wear on
>these components?
>
>-Mike

Dear Mike,

Coating things with hard grit like diamond dust turns them
into sandpaper, the opposite of the smooth surface that you
want.

Carl Fogel

Dear Jim,

So it looks as if at a fine enough level I'm wrong again.

I dunno, if you make the diamond fine enough you get graphite a pretty decent
lubricant. Well yeah, that's at the molecular level, but you did say "really
fine" didn't you.

Ron[/QUOTE]
No. Graphite is a planar crystalline unit cell allotrope of carbon. Diamond is a tetrahedral unit cell crystal. You cannot grind diamonds into graphite, you must pyrolyze and recondense the carbon vapors of a diamond to get graphite.

Unless you are riding in diamond dust, stick with nitriding of the chain.

Weisse Luft wrote in message ...

Quoted message said:

Dura Ace 9s chains have incredibly hard surface on the pins which places
all of the measurable wear (in my experience) on the flanged side
plates.

Looking under magnification at the older style pins (not center peened
like current), one could see this surface was cracked. Since the
cracks extended only to the riveted plate interface, wear was not
compromised but these cracks could promote corrosion. The current
peening method used shows none of this cracking.

I have only been able to "scratch" this surface with a diamond and
silicon carbide. Aluminum oxide does nothing to it but polish its
surface. Even hard carbide just slides over the surface.

Does this mean that perhaps my old Hyperglide chain was worth keeping, even
though the plating on the outer plates was ruined and made it ugly? I have
not examined the pins bearing surface, but I think it was OK as regards
'stretch'. I just threw it into a bag and put on a new chain for vanity. I
don't care now. When I next need a chain, I'll check that battered old
hyperglide.

Trevor