Kurt is right. Finding and fixing a tight link could resolve the issue. I've gotten so used to off-topic chains, with Power Link or similar connectors, that I forgot how common this was with new chains installed using a chain tool.
Earle Young Madison, Wisconsin Offering expert wheelbuilding services for classic and modern bicycles.
On Fri, Jan 1, 2010 at 10:41 AM, Kurt Sperry <haxixe@gmail.com> wrote:
> One not unlikely cause of similar symptoms can be simply a tight link
> in the chain. This is especially possible when this happens
> immediately after assembling a chain. I'd detension the chain and
> make sure every link flows over a falling curve with no binding, it
> might even be easier to remove the chain to perform this check. It
> will most likely be the point where you joined the chain last. This
> can be rectified by simply grabbing the chain on either side of the
> sticky link and applying a pretty vigorous side force to the chain
> back and forth until the link "flows". Whenever replacing a chain
> rivet I recommend checking it for free pivoting, it only takes a
> moment and can sometimes avoid later hassle.
>
> Kurt Sperry
> Bellingham, Washington
> USA
>
> On Fri, Jan 1, 2010 at 7:44 AM, earle.young tds.net <earle.young@tds.net>
> wrote:
> > John and list,
> >
> > Happy New Year to all.
> >
> > John asked, "When riding with much pressure on the pedals, the chain
> > "jumps", and what I mean by jumps, is that it crosses the top of the
> > freewheel gears. The freewheel is a Campagnolo Ergal with excellent teeth
> > and the chain is a new Everest slotted lightweight chain."
> >
> > Chain skip such as you describe is caused by a mis-match of chain and
> cog.
> > Even though your freewhwheel looks like it is in good condition, it is
> worn
> > enough that a chain roller is hitting the top of a cog instead of
> engaging
> > behind it. This will happen most frequently on the smaller cogs of a
> > freewheel, especially 13 or 12-tooth cogs, and even more commonly with
> alloy
> > cogs instead of steel cogs. Alloy freewheels wear very quickly, and are
> > considered special event equipment, even for professionals.
> >
> > Unfortunately, there is not much you can do to correct this except to get
> > new cogs or freewheel.
> >
> > Sorry to be the bearer of bad news.
> >
> > Earle Young
> > Madison, Wisconsin
> > Offering expert wheelbuilding services for classic and modern bicycles