Chain skipping under load(for no obvious reason)
 

Hi guys,
I built up a wheel around an old Sachs hub this winter. The cassette
had been used before, but still looked good with no obvious changes in
tooth shape. Anyhow, since this one is from way before shifting ramps
and all that I figured I'd flip the sprockets over to be really certain
that it would work well with the new chain I was putting on.
Well, it isn't. In the stand it runs as smooth as you'd ever wish for,
but when I try riding it I get skipping on both smallest AND largest
sprocket, and I just can't figure out why.

Teeth definitely appear symmetrical, the flipped-over side hasn't been
run before, there are no stiff links in the chain, I'm not
cross-chaining, so what's wrong with it?

Could a faulty chain length affect BOTH smallest and largets cog
performance while leaving the middle unaffected?

Can worn tension and jockey pulleys have anything to do with it?


--
dabac

Chain skipping under load(for no obvious reason)
 

On Mar 31, 3:04*am, dabac dabac.374...@no-
mx.forums.cyclingforums.com wrote:
Hi guys,
I built up a wheel around an old Sachs hub this winter. The cassette
had been used before, but still looked good with no obvious changes in
tooth shape. Anyhow, since this one is from way before shifting ramps
and all that I figured I'd flip the sprockets over to be really certain
that it would work well with the new chain I was putting on.
Well, it isn't. In the stand it runs as smooth as you'd ever wish for,
but when I try riding it I get skipping on both smallest AND largest
sprocket, and I just can't figure out why.

Teeth definitely appear symmetrical, the flipped-over side hasn't been
run before, there are no stiff links in the chain, I'm not
cross-chaining, so what's wrong with it?

Could a faulty chain length affect BOTH smallest and largets cog
performance while leaving the middle unaffected?

Can worn tension and jockey pulleys have anything to do with it?

Sounds weird, but make sure your cable guide under the BB is well
greased. Sometimes cable sticking can give you a problem that seems
like a bad cog/chain combo. Other problems may be: (1) bent
derailleur hanger, (2) bad derailleur (unlikely), (3) unseen stiff
link, (4) unseen wear on cogs, and (5) bad juju. Make sure you did
not sin in a past life. I doubt it is a pulley issue. That would
would not cause skipping, IMO. -- Jay Beattie.

Chain skipping under load(for no obvious reason)
 

Jay Beattie wrote:

Sounds weird, but make sure your cable guide under the BB is
well greased. Sometimes cable sticking can give you a problem
that seems like a bad cog/chain combo. Other problems may be:
(1) bent derailleur hanger, (2) bad derailleur (unlikely), (3)
unseen stiff link, (4) unseen wear on cogs, and (5) bad juju.
Make sure you did not sin in a past life. I doubt it is a
pulley issue. That would would not cause skipping, IMO. --

Following recent experience with my son's bike, make sure your
chain doesn't have a twist in it. One link got twisted on his,
so that the chain tried to derail once every trip over the
sprocket - but only under load.

John

Chain skipping under load(for no obvious reason)
 

On Mar 31, 2:26*pm, Jay Beattie wrote:
On Mar 31, 3:04*am, dabac dabac.374...@no-





mx.forums.cyclingforums.com wrote:
Hi guys,
I built up a wheel around an old Sachs hub this winter. The cassette
had been used before, but still looked good with no obvious changes in
tooth shape. Anyhow, since this one is from way before shifting ramps
and all that I figured I'd flip the sprockets over to be really certain
that it would work well with the new chain I was putting on.
Well, it isn't. In the stand it runs as smooth as you'd ever wish for,
but when I try riding it I get skipping on both smallest AND largest
sprocket, and I just can't figure out why.

Teeth definitely appear symmetrical, the flipped-over side hasn't been
run before, there are no stiff links in the chain, I'm not
cross-chaining, so what's wrong with it?

Could a faulty chain length affect BOTH smallest and largets cog
performance while leaving the middle unaffected?

Can worn tension and jockey pulleys have anything to do with it?

Sounds weird, but make sure your cable guide under the BB is well
greased. *Sometimes cable sticking can give you a problem that seems
like a bad cog/chain combo. *Other problems may be: (1) bent
derailleur hanger, (2) bad derailleur (unlikely), (3) unseen stiff
link, (4) unseen wear on cogs, and (5) bad juju. *Make sure you did
not sin in a past life. I doubt it is a pulley issue. *That would
would not cause skipping, IMO. -- Jay Beattie.- Hide quoted text -

- Show quoted text -

I had this problem last season for a couple rides of troubleshooting.
Like Jay says, it was the cable.

Chain skipping under load(for no obvious reason)
 

"John Henderson" wrote: (clip) make sure your
chain doesn't have a twist in it. (clip)
^^^^^^^^^^^^^^^^^
Moebius chain will do it every time.

Chain skipping under load(for no obvious reason)
 

Jay Beattie Wrote:
..make sure your cable guide under the BB is well
greased. Easy enough, will do.

Jay Beattie Wrote:
..Sometimes cable sticking can give you a problem that seems like a bad
cog/chain combo. But wouldn't that simply cause the RD to hesitate a little when
downshifting?
Jay Beattie Wrote:
.. Other problems may be: (1) bent
derailleur hanger, (2) bad derailleur (unlikely), (3) unseen stiff
link, (4) unseen wear on cogs,

No 1 is a possibility, the frame has been around for a while too.
Nothing immediately visible to the naked eye though.
Re. no 2 - there is a bit of slop in the RD, but I've seen far worse
that still performed better than this.
I find no 3 highly improbable. Chain was KMC straight out of the box,
put together with a quick link. Must have used dozens before, often by
pushing the pin back in instead of using a quicklink, never had any
trouble.
If it's no 4 then I'll never trust my eyes again. I swear the tooth
flanks on the flipped-over sprockets are pristine.

Jay Beattie Wrote:
... Make sure you did
not sin in a past life.

LOl, a bit late to think about that by now...

What's really weird IMO is that it's both smallest and biggest that are
affected while the middle ones runs as smooth as you could ever wish. I
almost suspect that:
a) original fit of tooth profile was bad, and got worn to fit by the
chain
b) I missed to flip the middle sprockets over.

But I can't really see a bike being sold with such a poor fit that it'd
require hundreds of miles of break-in riding before the chain would stop
skipping.


--
dabac

Chain skipping under load(for no obvious reason)
 

John Henderson Wrote: [color=blue]
Jay Beattie wrote:


Following recent experience with my son's bike, make sure your
chain doesn't have a twist in it. One link got twisted on his,
so that the chain tried to derail once every trip over the
sprocket - but only under load.

John

I'll look for that too - easy enough. Can't think of it when it'd have
happened though. Can't recall any chainsuck or derail incident.


--
dabac

Chain skipping under load(for no obvious reason)
 

Wrote:

I had this problem last season for a couple rides of troubleshooting.
Like Jay says, it was the cable.

Thanks for the tips guys, This afternoon I have another 16-mile chance
to figure it out...


--
dabac

Chain skipping under load(for no obvious reason)
 

On Mar 31, 4:04 am, dabac dabac.374...@no-
mx.forums.cyclingforums.com wrote:
Hi guys,
I built up a wheel around an old Sachs hub this winter. The cassette
had been used before, but still looked good with no obvious changes in
tooth shape. Anyhow, since this one is from way before shifting ramps
and all that I figured I'd flip the sprockets over to be really certain
that it would work well with the new chain I was putting on.
Well, it isn't. In the stand it runs as smooth as you'd ever wish for,
but when I try riding it I get skipping on both smallest AND largest
sprocket, and I just can't figure out why.

Teeth definitely appear symmetrical, the flipped-over side hasn't been
run before, there are no stiff links in the chain, I'm not
cross-chaining, so what's wrong with it?

Could a faulty chain length affect BOTH smallest and largets cog
performance while leaving the middle unaffected?

Can worn tension and jockey pulleys have anything to do with it?

--
dabac

Used sprockets don't work with new chains. As in your case, you'll end
up with a few sprockets that cause the chain to skip. Did you save the
old chain. If you did, use that one and use it with the cassette until
both are toast. otherwise, toss the cassette and get a new one.

To get long life out of a cassette, get two or three chains. clean and
lube all of them. Use one for a while. Then remove the chain out and
put the other one on, use it for a while and then switch to the third
chain. Wash and lube all three. Repeat process. Your chains and
cassette will work together for several thousand miles.

Andres

Chain skipping under load(for no obvious reason)
 

Wrote:
Used sprockets don't work with new chains.
Did you read the part about me flipping the sprockets over?

Sheldon's site has that listed as doable. Without sending off to a
metallurgy lab I'm as certain I can be that I'm running the new chain on
the previously unused sides of the teeth. Not that there was much wear
on the other side either.

Wrote:
... toss the cassette and get a new one.
Not really an option until I can do a frankenhub conversion and graft a
Shimano right flange on to the hub. It's an obsolete Sachs model and new
cassettes/sprockets are really hard to find.

Besides, given the symptoms I'm not so certain that a new Sachs
cassette would fix the problem.

Wrote:
Your chains and cassette will work together for several thousand miles.

...unless you're stubborn enough to ride your bike during winters where
roads gets sanded and salted...


--
dabac