Is my chain too long?

Tue, 24 Aug 2004 16:30:59 -0400, <[email hidden]>,

Bob Marchese said:

But is there some general principle that guides
these things that I could follow?

The length of the chain is determined by wrapping the chain around
both of the largest sprockets, without going through the derailleur
pulleys, and adding one complete link.

http://www.sheldonbrown.com/derailer-adjustment.html

Could it be the front derailleur over shifting or a bent chain ring?
--
zk

"Zoot Katz" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

Quoted message said:

The length of the chain is determined by wrapping the chain around
both of the largest sprockets, without going through the derailleur
pulleys, and adding one complete link.

No, wrap the chain around both the smallest sprockets
and cut it where it just starts to take up the derailleur
tension.

Bob Marchese said:

I just dusted off my old road bike (a 14 year old Raleigh Technium) and
started riding again. Last week the chain broke so I replace it with one of
the same size recommended by the LBS. I took it for a 15 miler over lunch
today and the chain came off the front sprocket no less than 3 times! This
doesn't seem right, so how do I fix it? I've got a chain tool so I could
remove a link or two, but it looks like there's no going back if that
doesn't help. I'm not even sure that's the problem since it is the same
length as the original one. I realize that this is a pretty general question
and not knowing the details of the parts involved it might be tough to
answer my question exactly. But is there some general principle that guides
these things that I could follow?

Is there reason to suspect that the chain you replaced was installed
properly? Or not?

The chain dropping off the front chainring can be caused by several
things. The first thing to check is front derailleur adjustment. The
next thing is to check for wear on the chainrings themselves. If the
teeth are very sharp, and very thin, probably the inter-tooth distance has
been stretched due to chain wear. Since this is a new chain on old rings,
that would tend to support my guess.

An extra link is the least likely cause of shifting trouble (OK, 3-4 extra
links might be a problem, but one, no). Misadjusted shifters are the most
likely, and chainring wear is next.

--

David L. Johnson

__o | "Business!" cried the Ghost. "Mankind was my business. The
_`\(,_ | common welfare was my business; charity, mercy, forbearance,
(_)/ (_) | and benevolence, were, all, my business. The dealings of my
trade were but a drop of water in the comprehensive ocean of my
business!" --Dickens, "A Christmas Carol"

Tue, 24 Aug 2004 23:12:08 GMT, <cXPWc.199717$M95.178734@pd7tw1no>,
Euro-Pro "Fabrizio Mazzoleni" <[email hidden]> corrected:

Quoted message said:

No, wrap the chain around both the smallest sprockets
and cut it where it just starts to take up the derailleur
tension.

That may be the way you pros do it with modern equipment.

Obviously the OP was seeking a more traditionally recognised method by
speaking of their '90's era Raleigh in other than a "retro" context.

Besides, just on the off chance they were a cyclist of your category,
the pictures provided by the link would be most helpful demonstrating
what is meant by the accompanying polysyllabic words.
--
zk

Though I generally encourage watching the road ahead when riding; have a
glance down at that chain and see if it's jumping around at all...if it
should go slack momentarily and then "jump" forward, your freewheel is
sticking a bit, probably needs some lube after all that storage time...

"Brian" wrote; Though I generally encourage watching the road ahead when
riding; have a glance down at that chain and see if it's jumping around at
all (clip)
^^^^^^^^^^^^^
Better yet, have a friend ride behind and to your right and watch it for
you.

"Brian" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Though I generally encourage watching the road ahead when riding; have a
glance down at that chain and see if it's jumping around at all...if it
should go slack momentarily and then "jump" forward, your freewheel is
sticking a bit, probably needs some lube after all that storage time...

I think an easier way to see this is to turn the crank backwards manually
while off the bike. If the freewheel(hub) is sticking, or if there are any
stiff chain links, you'll see the chain slack or jump in the rear derailer
respectively. You can also look for front derailer rubbing, chairing wobble
(bent or bolts loose), and bent teeth. It was the last problem that was
causing my son's bike to drop a chain while shifting last weekend.

Bob Marchese said:

answer my question exactly. But is there some general principle that guides
these things that I could follow?

Thanks for all the replies and especially the links to sheldonbrown.com (now bookmarked). It looks like it could be a combination of several things: worn sprockets, mis-adjusted front derailer, bent/broken teeth on both sprockets. I hope I can find replacement parts.