"Slipping" Power Train

On Nov 1, 9:12*pm, Phil W Lee wrote:
(Arthur Shapiro) considered Tue, 01 Nov 2011
19:06:25 GMT the perfect time to write:


My vote goes to new chain slipping on worn chainwheel.
Been there, done that, had the pedal bite (it was back in the days of
rat-traps and toe-straps).

Well, as long as we're voting, I like Jay's answer. I've seen a
chainring so worn that the chain slipped, but that level of wear is so
visible that I think Art wouldn't be asking us what the problem is.

That cable-to-bottom-bracket contact point does get sticky, and it's
easy to overlook.

- Frank Krygowski

WHAT'S

WHAT'S her credit line look like ?

On 11/2/2011 1:50 AM, Phil W Lee wrote:
Frank considered Tue, 1 Nov 2011
19:21:10 -0700 (PDT) the perfect time to write:

On Nov 1, 9:12 pm, Phil W wrote:
(Arthur Shapiro) considered Tue, 01 Nov 2011
19:06:25 GMT the perfect time to write:


My vote goes to new chain slipping on worn chainwheel.
Been there, done that, had the pedal bite (it was back in the days of
rat-traps and toe-straps).

Well, as long as we're voting, I like Jay's answer. I've seen a
chainring so worn that the chain slipped, but that level of wear is so
visible that I think Art wouldn't be asking us what the problem is.

The one that slipped on me didn't look all that worn.
Of course, if I'd kept trying to ride it, it pretty soon would have.
But most people probably still wouldn't notice it until it slipped, as
the tooth profile isn't all that obvious except on the big ring (and
not even on that if you have a guard-ring).
I've never been a masher, so someone who is could experience it with
even less wear.

That cable-to-bottom-bracket contact point does get sticky, and it's
easy to overlook.

I can't see how that would cause the symptom described.
And why would it start happening just after a chain/cassette
replacement?
Most people run through the gears after that to make sure all the
shifting is sweet, and would notice a slow or binding shift.

The sticky cable problem can be exacerbated by a light derailer spring.
Seeing how she recently replaced the derailer, that might explain it.

I had an Ultegra freehub start to skip like that, I had to replace it, I
assumed the pawls were worn. Switching to a larger rear sprocket (as she
did) will increase the torque on the pawls and make it more prone to skip.

Skipping problems can also be caused by worn/bent teeth or stiff chain
links, too. If the ring is significantly worn, I'd just replace it for
good measure. Stiff links are obvious, either by flexing by hand or
simply backpedaling and watching for jumps over the derailer pulley. If
I had a spare rear wheel, I'd try that out to eliminate the cassette and
hub.

On Nov 1, 2:13*pm, mike fee wrote:
In article ,
says...

She'd recently put an 11-34 cluster and some sort of mountain bike derailleur
on her Dura Ace-equipped Calfee. *She does a huge amount of monster
climbing. *The chain was replaced at the time but not the chainwheels..

If she replaced the chain but not the chainrings, and the rings are worn
to the point of shark-toothing, the chain could potentially slip out of
the chain-ring teeth and give a free-wheel effect. This has happened to
me a couple of times when I replaced chain on worn rings and was always
solved by replacing the rings.

Usually occured when starting off from stationary, which could just be
due to the higher torques at that time or because, when changing down to
a smaller ring when stopping, the chain didn't fully engage with the
worn teeth.

Mike

Sheldon Brown has a photo. But CR/Chain is visual: match rollers/
roller to CR/CR. Has the temp dropped ? Lower temps can glue cable to
housing, needs cleaning or admin Finish Line Dry Lube at joints. Place
a ball bearing in the FL bottle.

I once had a threaded 15-tooth (freewheel, not cassette) sprocket
slip because the thread stripped. It would give, turn 360 degrees,
then hold again (until the next time I pushed hard in that gear).
I doubt this is happening in the OP's case but I mention it for the
benefit of anyone trying to diagnose a similar problem that occurs
when using a threaded-on sprocket.

Tom Ace

On Nov 2, 4:13*pm, Tom Ace wrote:
I once had a threaded 15-tooth (freewheel, not cassette) sprocket
slip because the thread stripped.

There's always one. What year was it then you got the World's gold in
the mens sprint?

*It would give, turn 360 degrees,
then hold again (until the next time I pushed hard in that gear).
I doubt this is happening in the OP's case but I mention it for the
benefit of anyone trying to diagnose a similar problem that occurs
when using a threaded-on sprocket.

Tom Ace

Phil W Lee wrote:
Frank Krygowski considered Tue, 1 Nov 2011
19:21:10 -0700 (PDT) the perfect time to write:

That cable-to-bottom-bracket contact point does get sticky, and it's
easy to overlook.

I can't see how that would cause the symptom described.
And why would it start happening just after a chain/cassette
replacement?
Most people run through the gears after that to make sure all the
shifting is sweet, and would notice a slow or binding shift.

Some people don't know how to change gears and ask for the perfect gear
to be preselected.

--
JS.

On Nov 2, 12:50*pm, thirty-six wrote:
On Nov 2, 4:13*pm, Tom Ace wrote:

I once had a threaded 15-tooth (freewheel, not cassette) sprocket
slip because the thread stripped.

There's always one. *What year was it then you got the World's gold in
the mens sprint?

This happened to me with only one sprocket in 40 years of
riding bikes with freewheels. Sorry to let you down but it looks
like an instance of poor manufacturing, not a champion rider.

Tom