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

Weisse Luft wrote in message ...

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

jim beam wrote in message ...
depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Be careful, the misuse of such words will give away your identity XXXXX
XXXXXXX

Your omission from this news group seemed so unlikely that I guess this is
your pseudonym. I know, you know I know.

Trevor

jim beam wrote in message ...
depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Be careful, the misuse of such words will give away your identity XXXXX
XXXXXXX

Your omission from this news group seemed so unlikely that I guess this is
your pseudonym. I know, you know I know.

Trevor

"Trevor Jeffrey" a écrit dans le message de :
...

jim beam wrote in message ...
depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Be careful, the misuse of such words will give away your identity XXXXX
XXXXXXX

Your omission from this news group seemed so unlikely that I guess this is
your pseudonym. I know, you know I know.

Trevor


I wondered if I would have anything to read here, today. Trevor has made up
for August vacationers. Sadly, by adding him to my magic list, I will have
so much less to read from now on.

And Trevor - could you possibly be related to a Justin, of Bianchi fame ?
--
Bonne route,

Sandy
Paris FR

"Trevor Jeffrey" a écrit dans le message de :
...

jim beam wrote in message ...
depends on morphology. if it's sufficiently rough it will. if it's
smooth, and fine, it will extend wear considerably.

Be careful, the misuse of such words will give away your identity XXXXX
XXXXXXX

Your omission from this news group seemed so unlikely that I guess this is
your pseudonym. I know, you know I know.

Trevor


I wondered if I would have anything to read here, today. Trevor has made up
for August vacationers. Sadly, by adding him to my magic list, I will have
so much less to read from now on.

And Trevor - could you possibly be related to a Justin, of Bianchi fame ?
--
Bonne route,

Sandy
Paris FR

Smells like a go for a Guinness record ...
--
Bonne route,

Sandy
Paris FR


"Trevor Jeffrey" a écrit dans le message de :
...

Weisse Luft wrote in message ...

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

Smells like a go for a Guinness record ...
--
Bonne route,

Sandy
Paris FR


"Trevor Jeffrey" a écrit dans le message de :
...

Weisse Luft wrote in message ...

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

Trevor Jeffrey Wrote:
Weisse Luft wrote in message ...

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

Looking under magnification at the older style pins (not cente
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?
have
not examined the pins bearing surface, but I think it was OK a
regards
'stretch'. I just threw it into a bag and put on a new chain fo
vanity. I
don't care now. When I next need a chain, I'll check that battere
old
hyperglide.

Trevor

No, I pulled a Hyperglide chain off a bike that had several years o
college student inattention. Each pin had deep grooves in it from th
sideplates. Wear was about 1/4" over 12" of chain.

Dura Ace is much higher quality than low-level Hyperglide like HG-70

--
Weisse Luft

Trevor Jeffrey Wrote:
Weisse Luft wrote in message ...

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

Looking under magnification at the older style pins (not cente
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?
have
not examined the pins bearing surface, but I think it was OK a
regards
'stretch'. I just threw it into a bag and put on a new chain fo
vanity. I
don't care now. When I next need a chain, I'll check that battere
old
hyperglide.

Trevor

No, I pulled a Hyperglide chain off a bike that had several years o
college student inattention. Each pin had deep grooves in it from th
sideplates. Wear was about 1/4" over 12" of chain.

Dura Ace is much higher quality than low-level Hyperglide like HG-70

--
Weisse Luft

Weisse Luft wrote:
RonSonic Wrote:

On Sun, 15 Aug 2004 18:15:58 -0600, wrote:


On Sun, 15 Aug 2004 16:52:09 -0700, jim beam
wrote:


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

wrote:

On Thu, 12 Aug 2004 16:19:05 GMT, none
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

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.

ron may be alluding to some research that's been done on lubricants that
contain fine diamond - the idea being to take advantage of diamond's
thermal conductance while maintaining an acceptible wear rate.