On 9/17/2018 9:20 PM, Frank Krygowski wrote:
On 9/17/2018 3:58 PM, wrote:
On Sunday, September 16, 2018 at 4:37:42 PM UTC-7, AMuzi
wrote:
On 9/16/2018 6:11 PM, wrote:
I am trying to change the gearing on a beloved seventies
6/7 speed. I would like to use a 50-34 compact crankset
but stick with a 6 or 7 speed freewheel in back so I
don't have to change wheels and spread the frame. I need
rear derailleur ideas that could handle a 30T capacity
and a 28T rear cog. Do you have any suggestions? A
website suggested the Campagnolo Veloce 10 speed
derailleur, but when I tried this model, it doesn't
work, even with substituting longer adjustment screws
there was too much travel toward the spokes. Thanks.


With friction shifters a Veloce long cage should shift well.
You do need a longer low gear screw (m4x0.7) but you can
buy one for pennies at any hardware store.

Ensure derailleur is vertical (cage parallel to chainrings),
ensure chain length is adequate and then shift firmly with
your thumb like this:
http://www.yellowjersey.org/photosfr...t/gearchek.jpg
so you know absolutely that the chain will not shift off the
back of your low gear sprocket.

The low gear limit is the one on the left. You can see its
function by looking up from under the changer. Once the
shifter is adjusted properly, connect the gear wire. Have
another go, you just missed something.


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

Andrew, the springs that are supposed to hold the limit
screws in place are likely not to be long enough. I have
tried to use Blue Locktite but can't get it to work like
the stuff on many factory parts. Looking at these parts it
appears that you have to put a single drop of the blue
onto the screw and to let it dry for about an hour before
using it. But instead of getting a tighter screw fit the
damn things always are way too tight. And it's hard to get
a single drop at a time from the tube. Hard you got some
hints about this?


I doubt very much that a drop of typical Loctite thread
locker will ever dry on a screw. As I understand things,
it's an anaerobic adhesive, and its solidification is
triggered by the presence of metal ions AND the absence of
air. http://instantca.com/articles/anaerobic-adhesives/

Now Loctite has dozens of products, including many intended
for industrial use instead of consumer use. I don't doubt
they make a compound to pre-apply to screws that does turn
solid. But that's not the stuff normally sold in stores.

If you find out different, let me know.


Yes, that's right.
In practice, a drop of Blue on a screw will set in a few
hours once the threads are engaged (anaerobic). Alternately
for a simple low-force application like gear limit screws, a
drop of tubular cement works as well. Either may be turned
later as needed.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971