On Tuesday, June 15, 2021 at 10:51:00 PM UTC+2, wrote:
On Tuesday, June 15, 2021 at 10:30:00 AM UTC-7, 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.
Lou, every shifter will push further than a position without shifting. They are purposely designed that way so that if cable stretch allows you to not quite shift you can push it a little more without going into a higher gear but it will lift that slight amount. EVERY manual shifter is designed that way. Even the old SIS downtube shifters acted in exactly the same manner..

What this means is that you MUST set the upper and lower limit screws What this does, is to allow you to keep cable stretch from undershifting off of the bottom of the small cog. And it allows you to lift the chain slightly up into the higher gear that you cannot quite reach. So, if you don't have the upper limit screw set you CAN shift off of the top of the cogset and over into the spokes.

That cable stretch happens is shown by team mechanics leaning out of the team car and readjusting the cable.

I really don't quite get what you mean when you say that the limit screws aren't even needed.

Tom I really don't understand what you trying to say, but I am sure that on my one bike with mechanical shifting (Campy Super Record 11 speed) which is perfectly adjusted I can back off the limit screws without disaster to happen especially the upper limit screw (preventing the chain from dropping off the small cog) because after shifting to the smallest cog the RD spring will back it off from the limit screw. Back off the lower limit screw (largest cog) is not wise because on a hard climb and already in the lowest gear a lot of people hope they still have a lower gear and try to force the RD further towards the spokes. Like I said it is a (valuable) safety thing. Theoretically you don't need no limit screws with a perfectly adjusted RD and don't do something like forcing the RD towards a lower gear when you already in the lowest gear. Overshift is built in the shifter mechanism shifting to a lower gear and will happen also when you move the shifter just to the click. The RD backs off a bit when you release the shifter. You can see this very clearly on your Di2 setups every time you shift to a lower gear you see a little overshift and after a half a second or so backing off a bit. You can hear this. I'm done now.

Lou