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More Shifting Problems



 
 
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  #21  
Old June 15th 21, 11:53 PM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default More Shifting Problems

On Tue, 15 Jun 2021 12:31:17 -0700 (PDT), Sir Ridesalot
wrote:

On Tuesday, June 15, 2021 at 2:57:14 p.m. UTC-4, wrote:
On Tuesday, June 15, 2021 at 8:24:58 PM UTC+2, Frank Krygowski wrote:
On 6/15/2021 1:29 PM, Lou Holtman wrote:
On Tuesday, June 15, 2021 at 5:37:08 PM UTC+2, Frank Krygowski wrote:
On 6/15/2021 10:42 AM, Tom Kunich wrote:
On Monday, June 14, 2021 at 7:08:25 PM UTC-7, Frank Krygowski wrote:
On 6/14/2021 3:12 PM, Tom Kunich wrote:
On Monday, June 14, 2021 at 8:55:36 AM UTC-7, jbeattie wrote:

Your limit screw should not have any effect on the shifting in the middle of the cassette. Your problems sound like cable tension or a bent derailleur hanger or worn cogs in the middle of your cassette. Whether your derailleur pulleys have bearings or bushings isn't going to make any difference, although worn teeth may affect shifting.

Where did I say anything at all about the limit screw having anything to do with anything but to keep a derailleur from overshifting? While out on a ride I overshifted the rear derailleur. I caught it before there was any damage to the wheel but I did not want to overshift again so I readjusted the rear derailleur tension so that it would not overshift. That unfortunately screwed up the shifting so I had to ride in gears that were not effected.

Don't tell me you wouldn't do the same thing if you didn't have a screwdriver of the proper size to reset the limit screw.
Despite your long history of mechanical mishaps, you really went on a
bike ride with no tool capable of adjusting a tiny screw?

Why?? To save weight??

There is a reason that I was successful and you were a nothing that did nothing - I had the sense to know that simply turning an adjustment screw would get me back 10 miles where I could properly adjust things. People like you stop and block roads until cars get tired of your stupid bull****.
No, people like me turn the proper screw and ride on.

It sounds like you messed with cable length adjustment, screwing up your
shifting, when you should have messed with the limit screw and left your
shift levers in synch with your cog spacing.

Again: You should consider keeping your mistakes secret. You continually
tell us about your incompetence.


--
- Frank Krygowski


Again limit screws have nothing to do with the adjustment of your RD. I once explained that to a friend with a simple drawing:

https://photos.app.goo.gl/xT6x8vfz4hRwx9Y9A

If the chain is jumping between gears than:
- RD is not adjusted right,
- bent RD hanger,
- upper pulley wheel has to much radial play causing hysteresis which makes adjustment near impossible,
- B screw adjustment way off,
- outer plate of a chain link displaced,
- wrong cassette,
- the overshift feature in the shifter is gummed up and doesn't back up fast enough. I have only experience with Campy 9 and 10 speed shifters with this. I don't know how it works in a 11 and 12 sp shifter.

Adjustment of the limit screws is not in this equation.
A RD in an indexed system should be a matter of 5 minutes.
A nice drawing, but the interpretation is incomplete. Your drawing
appears to tell your friend how to synchronize the lever clicks with the
cogs - that is, adjust mid-range shifting. You don't deal with the
extreme positions, i.e. Tom's "overshifting."

You show no limit screws or other hard limits on the rear derailleur.
You also show no hard limits on the motion of the shift lever. So, in
your drawing, what happens if the user moves the shift lever clockwise,
past the last detent notch?

Answer: It would pull the derailleur past the largest cog, toward the
spokes. It would "overshift." For that reason, derailleurs have limit
screws. Or at least, every one I've worked on has had them.

If the limit screws have no function, why are they there?

It's true, of course, that those screws have nothing to do with
mid-range shifting. That's a cable [housing] length adjustment, and
perhaps a B screw adjustment (or your other diagnostic tips) for some
tougher cases.

It sounds like Tom tried to cure overshifting by adjusting the housing
length, thus making his mid-range shifting wonky. If he was
overshifting, he should have tightened a limit screw.

And of course, being Usenet, we may be conflating three different
problems. That's a frequent problem here.

I don't say limit screws have no function but they don't have anything to do with the adjustment of the RD. They are a safety thing in case someone tries to do shift beyond the largest cog.

Lou


Ah but Tom's original post was about his FRONT derailleur.

Cheers


Goodness! You don't mean that our hero Tommy has problems with both
front AND rear derailer? Perhaps he should switch to a single speed
bicycle which, well except for the BB, make all hrs problems go away.
And for a guy scraping by on the government dole, cheaper too :-)
--
Cheers,

John B.

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  #22  
Old June 16th 21, 12:52 AM posted to rec.bicycles.tech
Tom Kunich[_4_]
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Posts: 2,196
Default More Shifting Problems

On Tuesday, June 15, 2021 at 2:56:47 PM UTC-7, Frank Krygowski wrote:
On 6/15/2021 5:30 PM, Tom Kunich wrote:
On Tuesday, June 15, 2021 at 11:07:19 AM UTC-7, jbeattie wrote:

I think he tried to correct this at home, and it didn't work. It still shifted poorly. If he was putting his derailleur into the spokes, I wouldn't be surprised if he had a bent hanger.


Different bikes but what actually happened was that I installed an off-the-shelf rear derailleur and I expect I only set the lower limit. The upper limit screw was two full turns out of adjustment. Shifting EASY acted fine like Lou is trying to imply. But hitting a steep hill and having to shift pretty hard halfway up that 11%. It just pushed right over the large cog. Because the hill was so steep as soon as power came off the bike stopped. So no damage. But I assumed that the limit screw was just set a little off and loosened the cable a little. This worked fine except I would have to slightly overshift to get the middle gears to shift. And I was more careful to shift into low.

Yes. And I would have tightened the derailleur's low gear limit screw,
instead of loosening the cable. Shifting would have remained just as
good as before in the middle gears.

--
- Frank Krygowski

Tell us Frank, how many complete Campy Record 10 speed groups do you have?
 




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