Keiron said:Cheers Carl,
I do tend to neglect my chain, it would seem rather more obsessive chain
cleaning sessions required. however, what might be the problem for a rather
new 'driveset' as in original question which has very little wear? perhaps
unoiled, stiff links?
Cheers.
Keiron
Dear Keiron,
New chains comes from the factory with excellent, long-lasting
lubrication.
(That's the upshot of the familiar threads where people ask about how
to remove that greasy stuff that covers new chains.)
The usual causes for chain skip are worn gears, worn chains, or both.
You can also have a bad chain link--the master link is another brand
and not the same width, the connection pin wasn't inserted quite
right, or there's a stiff link whose pin needs to be eased.
Then there's the entirely separate problem of shifters that need
adjustment and horrible chainline.
Surprisingly, it's been show that a dry chain that has been cleaned of
all lubricant with solvent will run just fine and transmit as much
power, even though it probably squeaked like a box full of angry bats:
"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."
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf
Neither lack of lubrication nor excessive lubrication make bike chains
skip. Basically, you have to change the shape of the gear or the chain
to cause that kind of trouble.
Rust is also a possible culprit for the original poster's problem. A
rusty chain can give the stiff-link problem, just as it can provide
hidden wear that can't be easily measured--a single 12-inch pin-to-pin
check looks fine, but two feet away is a section of chain that rusted
and wore badly out of sight, either on the pins or on the rollers.
Rust is also more likely on a rarely used bike.
Or the problem can be something bizarre that can't be diagnosed over
the internet.
I once found that chain skip can be caused by little piece of fishing
line snarled in a derailleur pulley.
Another skip problem turned out to be a single link whose roller was
mysteriously missing--how the roller wore through and vanished is
beyond me, but there it was, a weird little gap in an otherwise worn
but still intact chain.
Cheers,
Carl Fogel
