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4605km from one chain: KMC X8 and Hebie Chainglider does the business

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Andre Jute

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Jun 16, 2011, 11:53:22 AM6/16/11
to
The KMC X8 chain, said by many to be the best derailleur chain in the
world, on my Rohloff-equipped Utopia Kranich is 0.75mm "stretched" at
4605 kilometres. What that means is that I can theoretically cover
another 1535km with the chain, or more sensibly that I should replace
the chain in the next 1535km, near enough a 1000 miles. I plan to
replace it as soon as the ordered replacement arrives.

Some details for those interested. This chain has run from new in a
fully enclosed and closely enveloping "oilbath" type chaincase,
initially in Utopia's pricey but fragile proprietary Country
chaincase, more recently in Hebie's Chainglider. It was run on its
factory lube for about a 1000km, and then given a few drops of Oil of
Rohloff at 500km intervals, the interval chosen as that at which the
Rohloff external clickbox gets a shot of the teflon. This proved to be
too much as it caused drips. When the external clickbox service
interval was increased to a 1000km, the chain service was increased
too. The drips stopped and visual inspection of the chain, and
measurement with a dedicated tool (made by X-Tools), showed that wear
did not increase noticeably. No cleaning whatsoever, and no other
service or maintenance was performed on this chain. Fit and forget,
except for a few drops of oil at 6-monthly intervals.

The bike runs on tarmac and most often in dry conditions but there is
no evidence that either water or grit has beaten the chaincases. The
rider is hefty (95 kilos or 210 pounds), and a masher, and bike and
gear weighs another 25kg or so. Frankly, I don't suppose a lighter
rider who used the gears more efficiently would get as much as 10%
more mileage. At these particular costs, which we'll discuss below, it
is isn't worth going to the slightest effort to stretch the chain life
a few hundred klicks.

Only the chain is being replaced. Rohloff's own cog shows teeth good
and square still, so I'm not turning it around this time; maybe next
time I fit a new chain (at 9000km cog use), maybe it will do 13,500 or
three chains' worth. The Indian Amar steel chainset still has the
black paint on the teeth, so I'm leaving that as well. (The Amar was
fitted in Germany unseen by me as a cheap temporary substitute while I
decided which crank I want. In well over two years I haven't found one
that isn't ugly or, if aesthetically suited, of too low a Q factor for
my bike's fat tackies and my wide stance.)

I've never had mileage this good on other chains used in chaincases.
SRAM's PC-1 and Shimano's Nexus chains gave up the ghost at about half
this distance on Shimano Nexus hub gearbox-equipped bikes.

I don't know how long a KMC X8 will last if not chaincased but it
seems likely that it will go at least half the distance, at least in
my on-road use.

The Utopia Kranich on which I ran the KMC X8 has a very long wheelbase
and needs a chain with 126 links. I therefore have to buy two chains
at Euro 13.90 each, discount price from my mailorder pusher,
Chainreactioncycles of Belfast. However CRC gives a further discount
if you buy three chains, so I ordered three chains for Euro 31.26, out
of which I will make two chains, good for about 9000km between them,
or about four and half years of cycling at my normal usage. We have to
add a package of two missing links, Euro 4.26, and a couple of bottles
of Oil of Rohloff, five Euro each, for a total of under 46 Euro. So,
if we account the chain case as part of the capital cost of the bike
(a doubtful proposition in the light of my experience of chaincases),
direct chain cost is about half a cent per kilometer.

Throw in the cost of a Hebie Chainglider, which seems likely to last
the distance of two chains, and chain costs are about a cent per
kilometer. Utopia's Country, assuming it lasts two years, which mine
didn't, will make the chain costs about three cents per kilometer. So
the Hebie Chainglider doubles the chain cost but also doubles chain
life (assumption); however, it also saves cleaning, maintenance and
laundry.

I have no argument with those who think the KMC X8 is the best chain
in the world; if true, it is a tremendous bargain even at the full
retail price. I do know from experience that the Hebie Chainglider and
the KMC X8 have given me mileage that I've never seen before.

Andre Jute
http://coolmainpress.com/andrejute.html

Chalo

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Jun 16, 2011, 12:56:20 PM6/16/11
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Andre Jute wrote:
>
> The KMC X8 chain, said by many to be the best derailleur chain in the
> world, on my Rohloff-equipped Utopia Kranich is 0.75mm "stretched" at
> 4605 kilometres.

Since not all chains measure 0% stretched when new, it's useful to
know where your chain started. I've come across new chains that
measured from less than zero elongation up to about 50% elongation.
(In fact none of them were elongated; what was being measured was
variation in roller diameters, internal clearances, etc.)

I think it's a good idea to replace the chain when it surpasses 0.5%
over the gauged elongation it started with, for the benefit of the
drivetrain's more expensive parts.

Chalo

Mike Jacoubowsky

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Jun 16, 2011, 1:09:01 PM6/16/11
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"Chalo" <chalo....@gmail.com> wrote in message
news:4f9ca008-1521-4d45...@j31g2000yqe.googlegroups.com...

Chalo: I agree, but I'm not sure he's got "expensive parts" to replace.
He refers to it as a "derailleur" chain, but it's a Rohloff hub in an
enclosed environment, leading me to believe he's got a nice, straight
path from single chainring up front to single cog in the rear. That
being the case, I'm actually surprised he isn't getting better life than
he is.

I tried out one of the german chains (stupid me can't recall which; it
was gold if that helps) on my nice bike, and it didn't get to .75% until
a ridiculous amount of mileage... about 3500... and I normally burn
through chains in less than 2000. But the shifting was never great with
that chain, new or old, and I was happy to get rid of it. But it did
give me an idea for what sort of mileage ought to be possible under
relatively-ideal conditions (like the drivetrain Andre may be
describing). 3500 miles for the way I ride, the condition I keep my bike
(far from clean), and my weight, and on a 10-speed cassette... my guess
is that a chain like that should do a whole lot better than 6000 miles
under Andre's conditions.

If I'm reading things right.

(For comparison purposes, if I replace a chain at 2000 miles, I can
easily get 5 chains/10,000 miles out of each cassette, and I've never
replaced one for skipping, just deteriorating shifting)

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


James

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Jun 16, 2011, 6:07:06 PM6/16/11
to
On 17/06/2011 3:09 AM, Mike Jacoubowsky wrote:
> "Chalo"<chalo....@gmail.com> wrote in message
> news:4f9ca008-1521-4d45...@j31g2000yqe.googlegroups.com...
>> Andre Jute wrote:
>>>
>>> The KMC X8 chain, said by many to be the best derailleur chain in the
>>> world, on my Rohloff-equipped Utopia Kranich is 0.75mm "stretched" at
>>> 4605 kilometres.
>>
>> Since not all chains measure 0% stretched when new, it's useful to
>> know where your chain started. I've come across new chains that
>> measured from less than zero elongation up to about 50% elongation.
>> (In fact none of them were elongated; what was being measured was
>> variation in roller diameters, internal clearances, etc.)
>>
>> I think it's a good idea to replace the chain when it surpasses 0.5%
>> over the gauged elongation it started with, for the benefit of the
>> drivetrain's more expensive parts.
>>
>> Chalo
>
> Chalo: I agree, but I'm not sure he's got "expensive parts" to replace.
> He refers to it as a "derailleur" chain, but it's a Rohloff hub in an
> enclosed environment, leading me to believe he's got a nice, straight
> path from single chainring up front to single cog in the rear. That
> being the case, I'm actually surprised he isn't getting better life than
> he is.

I was thinking that. 0.75mm stretched? If that is over 12" (304.8mm?),
it's only 1/4 worn.

In percentage terms;
0.75 * 100 / 304.8 = 0.246%

Fractions of an inch;
1/32 = 0.03152.
0.75/25.4 = 0.0295.

But still, the wear rate is not likely linear with mileage, according to
the chain wear test I've seen.

http://www.cantitoeroad.com/uploads/landingpage/connex/Chainwear_Test_10_Speed_10-JUN-2010.pdf

I've ridden about 5500km on my Campag chain and it's now 1/16"
stretched. (10s derailleur). I clean and lube about once every month.

--
JS.

Chalo

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Jun 16, 2011, 6:15:06 PM6/16/11
to
Mike Jacoubowsky wrote:

>
> Chalo wrote:
> >
> > I think it's a good idea to replace the chain when it surpasses 0.5%
> > over the gauged elongation it started with, for the benefit of the
> > drivetrain's more expensive parts.
>
> Chalo: I agree, but I'm not sure he's got "expensive parts" to replace.
> He refers to it as a "derailleur" chain, but it's a Rohloff hub in an
> enclosed environment, leading me to believe he's got a nice, straight
> path from single chainring up front to single cog in the rear. That
> being the case, I'm actually surprised he isn't getting better life than
> he is.

Fair enough. I think his mileage is commendable in absolute terms,
but I think I get better mileage than that at least sometimes, without
ever cleaning the chain or taking special measures. Or using a
chaincase.

Rohloff sprockets cost $40 or so, and once worn by a wrecked chain
will go on to prematurely wear out new chains in turn. You're right
that it is less of a functional or economical concern than the same
wear on a 9-, 10-, or 11-speed derailleur system.

> (For comparison purposes, if I replace a chain at 2000 miles, I can
> easily get 5 chains/10,000 miles out of each cassette, and I've never
> replaced one for skipping, just deteriorating shifting)

If only everyone were so attentive.

Chalo

Peter Rathmann

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Jun 16, 2011, 6:16:20 PM6/16/11
to
On Jun 16, 10:09 am, "Mike Jacoubowsky" <Mi...@ChainReaction.com>
wrote:

> Chalo: I agree, but I'm not sure he's got "expensive parts" to replace.
> He refers to it as a "derailleur" chain, but it's a Rohloff hub in an
> enclosed environment, leading me to believe he's got a nice, straight
> path from single chainring up front to single cog in the rear. That
> being the case, I'm actually surprised he isn't getting better life than
> he is.

That was my impression as well. The timing chain on our tandem has
over 20,000 miles on it and that's without the oil bath and chaincase
enclosure that Andre's using. Not clear why he's using such a narrow
chain for a single chainring/single cog application.

Tom Ace

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Jun 16, 2011, 7:06:42 PM6/16/11
to
Rohloff has a rider's report about a Gates belt
continuing to work fine after 18,000 km:
http://www.rohloff.de/de/sponsoring/berichte/mon_velo_gates_carbon_drive/index.html

I'd look into belt drive if I were getting another
Rohloff-equipped bike.

Tom Ace

Andre Jute

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Jun 16, 2011, 9:10:25 PM6/16/11
to

When I got the bike, I also had new tools delivered with it. The
standard chainchecker that clips around a roller at one end and at the
other tries to insert a tongue between rollers further along is
useless for this. I used a plain steel rule and two excellent quality
vernier calipers, one digital. As far as I could make out, by a
variety of measurements, the KMC X8 I received was to blueprint spec.

Also, it has recently started skipping cogs when I change gear under
power. It's a pain to adjust the chain length because I have so much
stuff that must be moved: fenders, rack, mudguards that fit
particularly closely...

I'll remember the 0.5% suggestion but it looks like the Rohloff cog,
the most expensive element in primary drivetrain, will outlive two
chains (9000km) easily on this side, possibly three (13500km)and then
can be turned around. We'll see.

Also, your reply to Peter implies that I could possibly do better. I
don't quite see how; this is getting on for twice as much mileage as
I've ever seen on chains from other makers that are not substantively
cheaper. It's gotta be something about me or my circumstances that is
common across all three hub gearbox bikes. I'm not concerned about it,
as the chain cost is already very low.

Thanks for the input.

Andre Jute

Andre Jute

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Jun 16, 2011, 9:23:27 PM6/16/11
to
On Jun 16, 6:09 pm, "Mike Jacoubowsky" <Mi...@ChainReaction.com>
wrote:
> "Chalo" <chalo.col...@gmail.com> wrote in message

>
> news:4f9ca008-1521-4d45...@j31g2000yqe.googlegroups.com...
>
>
>
>
>
> > Andre Jute wrote:
>
> >> The KMC X8 chain, said by many to be the best derailleur chain in the
> >> world, on my Rohloff-equipped Utopia Kranich is 0.75mm "stretched" at
> >> 4605 kilometres.
>
> > Since not all chains measure 0% stretched when new, it's useful to
> > know where your chain started.  I've come across new chains that
> > measured from less than zero elongation up to about 50% elongation.
> > (In fact none of them were elongated; what was being measured was
> > variation in roller diameters, internal clearances, etc.)
>
> > I think it's a good idea to replace the chain when it surpasses 0.5%
> > over the gauged elongation it started with, for the benefit of the
> > drivetrain's more expensive parts.
>
> > Chalo
>
> Chalo: I agree, but I'm not sure he's got "expensive parts" to replace.

I bought a spare Rohloff cog with the bike, and expect it to see me
out. 10K miles per side is not too much to expect and in a really good
year I ride 22 kilometres or about 1320 miles; this year has been so
bad, I've ridden just 524 klicks to today; heart surgery kept me off
the bike for about a fortnight. My crankset is Indian steel, under
twenty bucks in Germany, where it is popular. I was supposed to be a
temporary measure but I haven't found anything I like better.

> He refers to it as a "derailleur" chain, but it's a Rohloff hub in an
> enclosed environment, leading me to believe he's got a nice, straight
> path from single chainring up front to single cog in the rear. That
> being the case, I'm actually surprised he isn't getting better life than
> he is.

Ideal 54mm chainline, straight as a die. Rohloff recommends the use of
eight speed derailleur chains for their flexibility, and also
recommended the narrow type but I can't now find the text snippet I
saved; it seems to be no longer on their netsite.

> I tried out one of the german chains (stupid me can't recall which; it
> was gold if that helps) on my nice bike, and it didn't get to .75% until
> a ridiculous amount of mileage... about 3500... and I normally burn
> through chains in less than 2000. But the shifting was never great with
> that chain, new or old, and I was happy to get rid of it. But it did
> give me an idea for what sort of mileage ought to be possible under
> relatively-ideal conditions (like the drivetrain Andre may be
> describing). 3500 miles for the way I ride, the condition I keep my bike
> (far from clean), and my weight, and on a 10-speed cassette... my guess
> is that a chain like that should do a whole lot better than 6000 miles
> under Andre's conditions.
>
> If I'm reading things right.

You got it right. At around 6000 miles I'll reach 100% wear, and
presumably have to swap the cog as well.

> (For comparison purposes, if I replace a chain at 2000 miles, I can
> easily get 5 chains/10,000 miles out of each cassette, and I've never
> replaced one for skipping, just deteriorating shifting)

Hey, Mike, I beat an expert, even if it took me a couple of chaincases
(one of them godawfully expensive) to do it!

But there are guys on the Thorn Rohloff group who speak of 6K on open
chains used for commuting in all kinds of weathers as disappointing,
and several who get 10K.

> --Mike--     Chain Reaction Bicycleswww.ChainReactionBicycles.com

Andre Jute

Mike Jacoubowsky

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Jun 16, 2011, 9:27:49 PM6/16/11
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"Chalo" <chalo....@gmail.com> wrote in message
news:fe88ce30-5585-40d3...@h7g2000yqa.googlegroups.com...

It would be very convenient if bikes had odometers that accurately recorded
mileage no-matter-what (no batteries to wear out, always reliable). Then
when bikes came in for service, you could record mileage and get an accurate
idea of when to replace things in the future, and whether someone is getting
much better or much worse life than the norm (and try to figure out why).

Me? I'm not attentive at all. My riding routine simply happens to be pretty
regimented; I ride 31 miles each on Tuesdays & Thursdays, and on Sundays, it
varies from 50 to 112 miles, no matter what. Off-season Sunday average would
be closer to 50, otherwise 80. From that I can get a pretty good idea how
many miles I'm putting in during a given time period.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Andre Jute

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Jun 16, 2011, 9:27:44 PM6/16/11
to
On Jun 16, 11:07 pm, James <james.e.stew...@gmail.com> wrote:
> On 17/06/2011 3:09 AM, Mike Jacoubowsky wrote:
>
>
>
>
>
> > "Chalo"<chalo.col...@gmail.com>  wrote in message
> http://www.cantitoeroad.com/uploads/landingpage/connex/Chainwear_Test...

>
> I've ridden about 5500km on my Campag chain and it's now 1/16"
> stretched.  (10s derailleur).  I clean and lube about once every month.
>
> --
> JS.

Thanks for the math, James, but it's my ballsup -- I meant 0.75%, not
millimetres. Bloody hell, I'm surrounded by commuters who get these
amazing mileages on open chains when with a chaincase I can't even
come near. Only thing you can logically conclude is that rain and
carbon monoxide fumes make a seriously good lubricant for bicycle
chains. -- Andre Jute

Andre Jute

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Jun 16, 2011, 9:32:02 PM6/16/11
to

The narrow chain is recommended by Rohloff, or was, as I cannot now
find the text, only secondhand echoes of it as others also paraphrase
it. Hebie also has a width limit for their Chainglider which it is
wise to undercut for the most silent operation.

Is a timing chain on a tandem unloaded? -- apologies for the ignorance.

Andre Jute

unread,
Jun 16, 2011, 9:34:33 PM6/16/11
to
On Jun 17, 12:06 am, Tom Ace <tom...@gmail.com> wrote:
> Rohloff has a rider's report about a Gates belt
> continuing to work fine after 18,000 km:http://www.rohloff.de/de/sponsoring/berichte/mon_velo_gates_carbon_dr...

>
> I'd look into belt drive if I were getting another
> Rohloff-equipped bike.

So would I, Tom. It seems like the wave of the future. And I have a
steel bike that could be cut to allow fitting it. -- AJ

Andre Jute

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Jun 16, 2011, 9:37:26 PM6/16/11
to
Mea culpa. Of course, 0.75mm should read 0.75%.

James

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Jun 16, 2011, 9:51:33 PM6/16/11
to

Ah - that'll explain it. So, about 3/32" over 12". Hmm, I'd hope for a
bit better than that out of your setup.

The Wippermann test showed the KMC 10?? chains to be less resistant to
wear than some others, however I suspect your KMC chain is possibly less
than half the price of the others!

--
JS.

Tosspot

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Jun 17, 2011, 4:38:05 AM6/17/11
to
On 17/06/11 02:27, Mike Jacoubowsky wrote:

<snip>

> It would be very convenient if bikes had odometers that accurately recorded
> mileage no-matter-what (no batteries to wear out, always reliable). Then when
> bikes came in for service, you could record mileage and get an accurate idea of
> when to replace things in the future, and whether someone is getting much better
> or much worse life than the norm (and try to figure out why).

I remember these things from my yoof. I had no idea they were still available.

http://stores.ebay.ca/velomakak-one/Speedometer-Cyclometer-/_i.html?_fsub=2392738015

<snip>

Andre Jute

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Jun 17, 2011, 1:50:56 PM6/17/11
to

It is worth stressing that by, compared to my past history with
chains, this is a fabulous result. I'm very happy with it, and have
ordered the same KMC X8 chain again.

It also makes me wonder what you guys here and on the Rohloff sub-
conference at Thorn bikes, where I hang out a bit for the Rohloff
expertise, can be doing right that I'm not.

> The Wippermann test showed the KMC 10?? chains to be less resistant to
> wear than some others, however I suspect your KMC chain is possibly less
> than half the price of the others!

Not so. I was reporting discounted prices, plus a further discount for
a bulk buy. If you compare the recommended retail price, and like for
like (as far as I could find equivalents at CRC), KMC is unfortunately
not cheap.

KMC X8-93 half nickel (they don't make the X8 in all steel, which I
would buy if I could because inside a chain case the nickel is wasted)
EUR 16.23
Wippermann 800 EUR 13.90

KMC X8-99 all nickel (the one you would need if you don't have a
chaincase) EUR 20.86
Wippermann 808 EUR 20.86

The 10 speed chains in the same longlife construction and even the
cheapest finish are more expensive:

KMC X10-93 half nickel EUR 31.29
Wippermann 10SG brass plated (better than half-nickel!) EUR 38.25
KMC X10SL Gold EUR 75.36 (titanium nitride coated)
Wippermann 10S1 stainless EUR 75.36

Wippermann Connex are aspirational chains for a lot of folk... Looks
to me like KMC gets away with charging the same, and in some cases
more than Wippermann for equivalent chains, because they make a good
chain.

Andre Jute
A bicyclist, Your Honor. Hell's Angels are motorized.

Andre Jute

unread,
Jun 17, 2011, 1:52:27 PM6/17/11
to
> http://stores.ebay.ca/velomakak-one/Speedometer-Cyclometer-/_i.html?_...
>
> <snip>

Nooo! Your yoof couldn't possibly be that far back. Your father told
you about such things, to put off telling you about the birds and the
bees. -- AJ

Tosspot

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Jun 17, 2011, 5:16:34 PM6/17/11
to

Feckoff, I 'ad one I did, it was mine, bort from a shop right up the road, and
it went clickclickcrunch when the little spokey tabby thing slipped a bit. An I
used a leccy drill to put more miles on it to make me look 'ard I did.

And while I'm here, I *also* had one of the magic cable drive speedos on my *MK
I* Chopper! So there!

Dog, Raleigh Choppers, an abomination to mankind.

AMuzi

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Jun 17, 2011, 5:41:59 PM6/17/11
to
Tosspot wrote:
> Dog, Raleigh Choppers, an abomination to mankind.

Having sold those new, I think you are being too kind.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

Tºm Shermªn °_°

unread,
Jun 17, 2011, 11:02:18 PM6/17/11
to
On 6/17/2011 4:41 PM, A. Muzi wrote:
> Tosspot wrote:
>> Dog, Raleigh Choppers, an abomination to mankind.
>
> Having sold those new, I think you are being too kind.
>

Even when gold-plated by "Needless Markup":
<http://farm4.static.flickr.com/3266/2580813127_3d79f005cc.jpg>?

--
Tºm Shermªn - 42.435731,-83.985007
I am a vehicular cyclist.

Peter Rathmann

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Jun 18, 2011, 1:15:33 AM6/18/11
to
On Jun 16, 6:32 pm, Andre Jute <fiult...@yahoo.com> wrote:
> On Jun 16, 11:16 pm, Peter Rathmann <prathm...@yahoo.com> wrote:
>
...

> > That was my impression as well.  The timing chain on our tandem has
> > over 20,000 miles on it and that's without the oil bath and chaincase
> > enclosure that Andre's using.  Not clear why he's using such a narrow
> > chain for a single chainring/single cog application.
>
> The narrow chain is recommended by Rohloff, or was, as I cannot now
> find the text, only secondhand echoes of it as others also paraphrase
> it. Hebie also has a width limit for their Chainglider which it is
> wise to undercut for the most silent operation.
>
> Is a timing chain on a tandem unloaded? -- apologies for the ignorance.

What's referred to as the 'timing chain' on a tandem is the chain
linking the front and rear cranks. It's a bit of a misnomer since it
transfers the power of the front rider to the rear crank and is
therefore loaded with similar tension as the chain on a single bike
(with variations depending on rider strength and the choice of
chainring size).

James

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Jun 18, 2011, 2:36:00 AM6/18/11
to

That's good.

> It also makes me wonder what you guys here and on the Rohloff sub-
> conference at Thorn bikes, where I hang out a bit for the Rohloff
> expertise, can be doing right that I'm not.

Maybe a more thorough cleaning once in a while would help? Does the
oil still become black? A good cleaning and fresh oil might be the
shot.

> > The Wippermann test showed the KMC 10?? chains to be less resistant to
> > wear than some others, however I suspect your KMC chain is possibly less
> > than half the price of the others!
>
> Not so. I was reporting discounted prices, plus a further discount for
> a bulk buy. If you compare  the recommended retail price, and like for
> like (as far as I could find equivalents at CRC), KMC is unfortunately
> not cheap.
>
> KMC X8-93 half nickel (they don't make the X8 in all steel, which I
> would buy if I could because inside a chain case the nickel is wasted)
> EUR 16.23
> Wippermann 800 EUR 13.90
>
> KMC X8-99 all nickel (the one you would need if you don't have a
> chaincase) EUR 20.86
> Wippermann 808 EUR 20.86
>
> The 10 speed chains in the same longlife construction and even the
> cheapest finish are more expensive:
>
> KMC X10-93 half nickel EUR 31.29
> Wippermann 10SG brass plated (better than half-nickel!) EUR 38.25
> KMC X10SL Gold EUR 75.36 (titanium nitride coated)
> Wippermann 10S1 stainless EUR 75.36
>
> Wippermann Connex are aspirational chains for a lot of folk... Looks
> to me like KMC gets away with charging the same, and in some cases
> more than Wippermann for equivalent chains, because they make a good
> chain.

I see they're not so cheap. I hadn't looked at them. The Wippermann
test shows the KMC X10SL Gold to last 68 hours till 1% stretch,
compared with 94 hours for the Campag. Veloce and 114 for the Connex
10sX.

That's a big difference in durability/wear rate, and all similar
prices.

--
JS.

Chalo

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Jun 18, 2011, 2:58:32 AM6/18/11
to
Peter Rathmann wrote:
>
> Andre Jute wrote:

> >
> > Peter Rathmann wrote:
> > >
> > > The timing chain on our tandem has
> > > over 20,000 miles on it and that's without the oil bath and chaincase
> > > enclosure that Andre's using.  
> >
> > Is a timing chain on a tandem unloaded? -- apologies for the ignorance.
>
> What's referred to as the 'timing chain' on a tandem is the chain
> linking the front and rear cranks.  It's a bit of a misnomer since it
> transfers the power of the front rider to the rear crank and is
> therefore loaded with similar tension as the chain on a single bike
> (with variations depending on rider strength and the choice of
> chainring size).

One critical difference between a tandem timing chain and a one-speed
drive chain is the size of the driven sprocket-- typically 39t. That
alone makes it almost infinitely gentler on a chain than a one-speed
drive featuring the same chain tension and drive sprocket size but a
14t to 18t driven sprocket. The tandem's front chain articulates
through a much smaller angle and at any moment shares the load among
many more teeth on the driven sprocket.

Chalo

carl...@comcast.net

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Jun 18, 2011, 4:48:39 PM6/18/11
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Dear Chalo,

When a chain link on the tight side rolls onto any sprocket, the
tension drops to almost nothing within only two teeth:

"The tension in a chain link decreases very rapidly as the link enters
the drive sprocket. The decrease from tight side to average loose side
tension occurs over less than two sprocket teeth."

http://deepblue.lib.umich.edu/bitstream/2027.42/4402/4/bac0175.0001.001.txt

The load on a sprocket tooth is roughly similar to the load on a screw
thread--only the first few teeth or threads see any load.

In other words, only the first two teeth share the load at any moment,
no matter how many teeth beyond them are wrapped with chain.

The smaller articulation angle of a chain on a larger sprocket reduces
chain wear (which in turn reduces tooth wear).

The smaller chordal action of the chain on the larger sprocket also
reduces chain and tooth wear.

The tooth wear is also reduced by the distribution of the tension over
time over more teeth--any single tooth on a 10-tooth sprocket sees 10%
of the work, while any single tooth on a 20-tooth sprocket sees only
5% of the work

Cheers,

Carl Fogel

T

Kerry Montgomery

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Jun 18, 2011, 9:55:37 PM6/18/11
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And, if the front rider just keeps cadence with the rear rider, there's
hardly any load on this chain...


Jay Beattie

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Jun 19, 2011, 11:54:48 AM6/19/11
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> hardly any load on this chain...- Hide quoted text -

Or a whole lot of load if your stoker is a freeloader. That's not a
Zefal pump . . . it's a cattle prod! Another deal with timing chains
is that you can use a 5sp chain if you want.

-- Jay Beattie.

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