On Sat, 3 Nov 2018 20:45:21 -0400, Frank Krygowski
wrote:

On 11/3/2018 6:26 PM, Emanuel Berg wrote:
After riding this bike a couple of weeks with
no problem, shifting out, to smaller sprockets
on the casette have started to trouble,
sometimes nothing happens when I click.
If I understand the theory correctly, this is
because the cable is too tight, and you should
turn the barrel in (clockwise) to make it more
slack. This actually worked, but how can it
happen that the cable is too tight suddenly?
Shouldn't it be more loose rather?

In my experience and if I recall correctly, the "settling" of a new
cable over time usually causes the other error, a reluctance to shift to
a bigger rear cog.

I wonder if the cable is somehow sticking. Shifting to smaller cogs is
powered only by the spring in the derailleur. If there's too much
friction on the cable, that spring might not be able to do its job.

The first place I'd check is where the shift cable changes direction
near the bottom bracket. Many bikes route the cable through a plastic
guide under the bottom bracket. Dirt and gunk down there can mess with
shifting. Older bikes may have a brazed on cable guide above the bottom
bracket which can also benefit from lubrication. Also check wherever
the bare cable enters some cable housing. Make sure it flows free.

For me, paraffin wax works well in those places as a dry lube that
doesn't gather dirt and turn it to mud. But lubricate with whatever you
like.

There are "cables" that have the inner cable coated with plastic that
is supposed to make them super slippery although to be honest, I tried
a couple and couldn't see any difference :-)

cheers,

John B.