Freeing up stuck derailleur pantogram

On 2021-02-04, AMuzi wrote:
On 2/4/2021 1:01 AM, D. Pureheart Steinbruner wrote:
Trying out slrn...hope I can get it to work okay.

My old SunTour XCPro was getting old and tired, the jockey wheels (idler
sprockets?) were worn down and annoyingly, it would not shift into 6th gear
on the freewheel (SunTour Ultra 6 or Winner pro, something like that).

I put on an old XCD out of my junk box (complete w/ red bullseye type
pulleys) and life was good again.

BUT...it did not take long before the darn thing gummed up and would not
shift back down to smaller cogs *at all*. This was about over the course of
a month. I've not put many miles on this year so far, so it's been in the
garage and it's been rainy and I'm only a few miles from the coast as the
crow flies...but....still.

I released the cable and confirmed that the thing was frozen up. A few
drops of oil has set things mostly to right on the pivots...but really..

Q; Should I have used oil or something lighter?
Q: What about simply a propane torch?
Q: Should I pry the joints apart ever so slightly of the pantogram assembly
to loosen things up?

It still won't go onto the smallest cog...just like the old one.

I've never really had this problem pop up like this which is why I ask if I
should pry at the joints or something.

pH in Aptos


Replacing the rollers in your XC Pro is a good path too.

Good for you to disconnect the gear wire so as to identify
an actual body problem. After sitting around for 30 years it
could be corrosion in the pivots or maybe just dried
lubricant. Oil is fine, every year or more depending on
ambient crud and frequency of use. For recalcitrant body
pivots try Rock-N-Roll it's especially effective in those.

Do not use heat and do not try to prise open the pivots.

If you have compressed air available, lubricate and work the
pivots at the bench, spray out, repeat until there's no more
crud escaping then oil well, wipe and re install. I would
assume given your area that you have dried lubricant in
there and not sal****er corrosion which means a complete
victory is very likely with small effort.

If your XCD body shows pavement scars from being smashed and
does not respond to clean/lube, then I would go with the XC Pro.

Thank-you for these pointers...no heat, no crowbar...got it!
pH

On 2021-02-04, Frank Krygowski wrote:
On 2/4/2021 10:17 AM, AMuzi wrote:
On 2/4/2021 1:01 AM, D. Pureheart Steinbruner wrote:
Trying out slrn...hope I can get it to work okay.

My old SunTour XCPro was getting old and tired, the jockey wheels (idler
sprockets?) were worn down and annoyingly, it would not shift into 6th
gear
on the freewheel (SunTour Ultra 6 or Winner pro, something like that).

I put on an old XCD out of my junk box (complete w/ red bullseye type
pulleys) and life was good again.

BUT...it did not take long before the darn thing gummed up and would not
shift back down to smaller cogs *at all*.Â* This was about over the
course of
a month.Â* I've not put many miles on this year so far, so it's been in
the
garage and it's been rainy and I'm only a few miles from the coast as the
crow flies...but....still.

I released the cable and confirmed that the thing was frozen up.Â* A few
drops of oil has set things mostly to right on the pivots...but really..

Q; Should I have used oil or something lighter?
Q: What about simply a propane torch?
Q: Should I pry the joints apart ever so slightly of the pantogram
assembly
to loosen things up?

It still won't go onto the smallest cog...just like the old one.

I've never really had this problem pop up like this which is why I ask
if I
should pry at the joints or something.

pH in Aptos


Replacing the rollers in your XC Pro is a good path too.

Good for you to disconnect the gear wire so as to identify an actual
body problem. After sitting around for 30 years it could be corrosion in
the pivots or maybe just dried lubricant.Â* Oil is fine, every year or
more depending on ambient crud and frequency of use. For recalcitrant
body pivots try Rock-N-Roll it's especially effective in those.

Do not use heat and do not try to prise open the pivots.

I strongly agree!

If you have compressed air available, lubricate and work the pivots at
the bench, spray out, repeat until there's no more crud escaping then
oil well, wipe and re install. I would assume given your area that you
have dried lubricant in there and not sal****er corrosion which means a
complete victory is very likely with small effort.

If your XCD body shows pavement scars from being smashed and does not
respond to clean/lube, then I would go with the XC Pro.

I'd spend some time moving the derailleur body by hand, carefully
feeling and looking to see if I could spot the source of friction. And
yes, I'd flush every moveable joint repeatedly with penetrating oil (I
like PB Blaster) then lube with light oil.

On at least some SunTour derailleurs (like the Superbe Pro on one of my
bikes) the main spring ends in a sort of loop that has sliding contact
with the inner surface of a parallelogram arm. That sliding contact can
get sticky and hamper shifting to smaller cogs. Be sure it's nice and slick.

Hmm. Okay, guess I'll be popping if off--thanks for this tip, too.
ph

On Fri, 5 Feb 2021 06:19:32 -0000 (UTC), "D. Pureheart Steinbruner"
wrote:

Well, the heck of it is that it worked perfectly well at first and only had
to sit a few weeks in my garage to freeze up.

The garage temperature might be cold enough to turn the lube oil to
tar.

While it's mostly functional just wondered what is preferred lube or maybe
propane torch *then* lube.

I use either sewing machine or clock oil for lubricating rotating
bicycle parts. Constant viscosity with temperature, doesn't stain my
clothes, doesn't evaporate and turn to tar, and is fairly cheap.
https://www.google.com/search?q=sewing+machine+oil+bicycle
I have both the mineral oil versions and the synthetics. The
synthetics do much better at high temperatures, which hopefully your
bicycle will never see. Otherwise, both types seem about the same. I
use these because I have a fairly good supply of these oils from other
projects, and I haven't had any problems using them. Unfortunately,
I've never used these oils on a derailleur pantograph and have no idea
what might happen.

Also, I suggest that you try my standard method of dealing with
unknown devices. I tear everything apart, inspect everything, and
clean everything. This doesn't really fix anything, but does give me
an excuse to closely inspect all the parts for wear, damage, and
foreign debris. The culprit usually appears during the inspection. It
also gives me an opportunity to learn how it works. In theory, once I
understand how something works, I can usually fix it.
https://www.thisiscolossal.com/2013/05/things-come-apart-a-new-book-of-disassembled-objects-by-todd-mclellan/
Well, maybe not quite "usually".

Good luck.


--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

Am 05.02.2021 um 02:16 schrieb Frank Krygowski:
Also, while I haven't experienced it, I've wondered about the myriad
stories about cars with sagging springs. Yes, it seems the only way a
suspension spring should sag is if its yield strength is exceeded, and
that should be impossible with good design. But are all those tales
false? I don't know.

I guess it was not uncommon to overload cars by a huge amount. Filling
up a van with a ton of wood when max load is less than half a ton
certainly damages the dampers, it might also damage the springs, causing
sagging in the long run.

On 2/5/2021 12:55 AM, Jeff Liebermann wrote:
On Fri, 5 Feb 2021 06:19:32 -0000 (UTC), "D. Pureheart Steinbruner"
wrote:

Well, the heck of it is that it worked perfectly well at first and only had
to sit a few weeks in my garage to freeze up.

The garage temperature might be cold enough to turn the lube oil to
tar.

While it's mostly functional just wondered what is preferred lube or maybe
propane torch *then* lube.

I use either sewing machine or clock oil for lubricating rotating
bicycle parts. Constant viscosity with temperature, doesn't stain my
clothes, doesn't evaporate and turn to tar, and is fairly cheap.
https://www.google.com/search?q=sewing+machine+oil+bicycle
I have both the mineral oil versions and the synthetics. The
synthetics do much better at high temperatures, which hopefully your
bicycle will never see. Otherwise, both types seem about the same. I
use these because I have a fairly good supply of these oils from other
projects, and I haven't had any problems using them. Unfortunately,
I've never used these oils on a derailleur pantograph and have no idea
what might happen.

Also, I suggest that you try my standard method of dealing with
unknown devices. I tear everything apart, inspect everything, and
clean everything. This doesn't really fix anything, but does give me
an excuse to closely inspect all the parts for wear, damage, and
foreign debris. The culprit usually appears during the inspection. It
also gives me an opportunity to learn how it works. In theory, once I
understand how something works, I can usually fix it.
https://www.thisiscolossal.com/2013/05/things-come-apart-a-new-book-of-disassembled-objects-by-todd-mclellan/
Well, maybe not quite "usually".

Good luck.



Good choices. Sewing machine oil was also sold as "Sturmey
Archer Cycle Oil" at one time.

https://www.ebay.co.uk/itm/Vintage-S...4AAOSw2w5gHUn4

For things with tight clearances which are stuck, try
Rock-N-Roll. It's unearthly in its penetration. I know this
sounds like a tout but it really is exceptional.

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

On Thursday, February 4, 2021 at 8:16:26 PM UTC-5, Frank Krygowski wrote:



But I've come across other broken springs. A coil spring broke on my
mom's Ford Taurus many, many years ago. (It became part of the pile of
broken mechanical parts I used for class illustrations.) I broke a
torsion bar (which is a type of spring) on a Honda Civic, and used it in
class as well. Now in both those cases, it's possible (or likely?) that
the initial problem was corrosion attacking the spring steel and
generating stress risers; but they were certainly broken.

Torsion springs are significantly more susceptible to damage from a high transient stress (i.e. impact) than a steel spring. That said, I've always been told the most common fracture point for an automotive coil spring is at the mounting point rather than any of the actual coil section, and also usually a result of a high transient stress. I'd also imagine the quality control processes for manufacturing automotive suspension springs are a but more relaxed - allowing for more contaminants and deformities: cyclists don't mind dropping well over $100 on derailleur, but most people balk at the same price for a MacPherson strut assembly. Related anecdote: I can remember my ex-wife giving me grief over my not wanting to spend $400 on a set of car tires, when I had just spent $90 on a Vittoria sew-up (back when they were still made in Italy).

On 2/5/2021 10:13 AM, AMuzi wrote:
On 2/5/2021 12:55 AM, Jeff Liebermann wrote:
On Fri, 5 Feb 2021 06:19:32 -0000 (UTC), "D. Pureheart Steinbruner"
wrote:

Well, the heck of it is that it worked perfectly well at first and
only had
to sit a few weeks in my garage to freeze up.

The garage temperature might be cold enough to turn the lube oil to
tar.

While it's mostly functional just wondered what is preferred lube or
maybe
propane torch *then* lube.

I use either sewing machine or clock oil for lubricating rotating
bicycle parts.Â* Constant viscosity with temperature, doesn't stain my
clothes, doesn't evaporate and turn to tar, and is fairly cheap.
https://www.google.com/search?q=sewing+machine+oil+bicycle
I have both the mineral oil versions and the synthetics.Â* The
synthetics do much better at high temperatures, which hopefully your
bicycle will never see.Â* Otherwise, both types seem about the same.Â* I
use these because I have a fairly good supply of these oils from other
projects, and I haven't had any problems using them.Â* Unfortunately,
I've never used these oils on a derailleur pantograph and have no idea
what might happen.

Also, I suggest that you try my standard method of dealing with
unknown devices.Â* I tear everything apart, inspect everything, and
clean everything.Â* This doesn't really fix anything, but does give me
an excuse to closely inspect all the parts for wear, damage, and
foreign debris.Â* The culprit usually appears during the inspection. It
also gives me an opportunity to learn how it works.Â* In theory, once I
understand how something works, I can usually fix it.
https://www.thisiscolossal.com/2013/05/things-come-apart-a-new-book-of-disassembled-objects-by-todd-mclellan/

Well, maybe not quite "usually".

Good luck.



Good choices. Sewing machine oil was also sold as "Sturmey Archer Cycle
Oil" at one time.

https://www.ebay.co.uk/itm/Vintage-S...4AAOSw2w5gHUn4


For things with tight clearances which are stuck, try Rock-N-Roll.Â* It's
unearthly in its penetration. I know this sounds like a tout but it
really is exceptional.

Lately I've been using Dextron VI automatic transmission fluid for
lubricating things like this, including my SA hub. I use it in a
refilled needle oiler. I'm sure the one quart I bought is a lifetime supply.

--
- Frank Krygowski

On 2/4/2021 8:08 PM, News 2021 wrote:


Use a spring enough, and it will weaken.

Not necessarily, for any practical definition of "enough."

In fact, I'd say not usually.


--
- Frank Krygowski

On Friday, February 5, 2021 at 10:57:21 AM UTC-5, Frank Krygowski wrote:
On 2/4/2021 8:08 PM, News 2021 wrote:


Use a spring enough, and it will weaken.
Not necessarily, for any practical definition of "enough."

In fact, I'd say not usually.

I'd go as far as saying a derailleur spring should last for the lifetime of the derailleur, barring manufacturing defects

On Fri, 05 Feb 2021 09:13:18 -0600, AMuzi wrote:

On 2/5/2021 12:55 AM, Jeff Liebermann wrote:
On Fri, 5 Feb 2021 06:19:32 -0000 (UTC), "D. Pureheart Steinbruner"
wrote:

Well, the heck of it is that it worked perfectly well at first and only had
to sit a few weeks in my garage to freeze up.

The garage temperature might be cold enough to turn the lube oil to
tar.

While it's mostly functional just wondered what is preferred lube or maybe
propane torch *then* lube.

I use either sewing machine or clock oil for lubricating rotating
bicycle parts. Constant viscosity with temperature, doesn't stain my
clothes, doesn't evaporate and turn to tar, and is fairly cheap.
https://www.google.com/search?q=sewing+machine+oil+bicycle
I have both the mineral oil versions and the synthetics. The
synthetics do much better at high temperatures, which hopefully your
bicycle will never see. Otherwise, both types seem about the same. I
use these because I have a fairly good supply of these oils from other
projects, and I haven't had any problems using them. Unfortunately,
I've never used these oils on a derailleur pantograph and have no idea
what might happen.

Also, I suggest that you try my standard method of dealing with
unknown devices. I tear everything apart, inspect everything, and
clean everything. This doesn't really fix anything, but does give me
an excuse to closely inspect all the parts for wear, damage, and
foreign debris. The culprit usually appears during the inspection. It
also gives me an opportunity to learn how it works. In theory, once I
understand how something works, I can usually fix it.
https://www.thisiscolossal.com/2013/05/things-come-apart-a-new-book-of-disassembled-objects-by-todd-mclellan/
Well, maybe not quite "usually".

Good luck.

Good choices. Sewing machine oil was also sold as "Sturmey
Archer Cycle Oil" at one time.

https://www.ebay.co.uk/itm/Vintage-S...4AAOSw2w5gHUn4

Sewing machine and clock oils are usually based on common mineral oil.
The polymers in the oil are cracked into smaller lengths to give it a
lower viscosity. However, all petroleum based oils have the
irritating habit of attacking rubber seals and plastic parts. You
won't find that in a clock or sewing machine, both of which are mostly
metal on metal. So, the synthetic sewing machine substitutes are used
for those situations where the oil needs to touch rubber or plastic
(or possibly paint). What I like about all of them is that they act
the same whether hot, cold, wet, or dry.

For things with tight clearances which are stuck, try
Rock-N-Roll. It's unearthly in its penetration. I know this
sounds like a tout but it really is exceptional.

https://www.rocklube.com
I'll give it a try. Ummm... which version?
https://www.rocklube.com/products.html
I'll look at the MSDS sheet later. My guess(tm) is that it's mostly
mineral oil or a silicon based synthetic.

My favorite penetrating oil is Kroil, which is banned in the Peoples
Republic of California. I was somewhat involved in this mess:
https://ww2.arb.ca.gov/kano-laboratories-inc-settlement
I guess I shouldn't mention that I have a few unmarked cans of ozone
depleting Kroil left in my secret stash. No, you can't have any.
https://www.kroil.com


--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558