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-   -   fine tuning shimano - cant get the last 10% (https://www.bikeforums.net/showthread.php?t=1210196)

wilson_smyth 08-13-20 10:54 AM

fine tuning shimano - cant get the last 10%
 
Ive been adjusting my commuter bike after its first 300+ km.
After tuning the rear derailleur is about 90% but there are a few small things that are niggling me and a few hours of fine tuning has not sorted it.

First off, my methodology was:
- release the cable holding screw/bolt.
- Turn the fine tuner on the derailleur all the way clockwise.
- turn the pedals and push the derailleur to get the chain to the 2nd smallest cog with my hand.
- pull the cable, not too hard but enough to pick up slack and tighten it onto the derailleur.
- starting on the smallest cog, click the changer back one. adjust the fine tune counter clockwise until it changes smoothly with no clicking.
- do this for all cogs.
- if chain is falling off either side or clicking on the biggest or smallest ring, adjust the limit screws.

I followed the process found on the you tube vid "How to Adjust your Shimano Rear Derailleur | #CGT - Bike School" (i cant post links)
Its mostly smooth now except for on the 2nd largest cog, there is slight clicking, if i adjust the fine tuner to get rid of this clicking, the change from the smallest to 2nd smallest ring becomes rough.

The bike is only 3 months old, sparsely used, is almost mollycoddled so gets no abuse outside from a 15-20 mile cycle on clean roads every second day.
Would appreciate any pointers in how to get it the last 10%.

trailangel 08-13-20 11:06 AM

4 Attachment(s)
Read the directions for adjusting Shimano Rear DR from Shimano.
Take note... adjust high limit screw so top pulley is just outside of smallest sprocket.
Attach the cable correctly to the DR... Attach the cable correctly to the DR... attach the cable....

Iride01 08-13-20 11:18 AM

Did you tell us what it is that you need the last 10% of?

If this is a 11 or even 10 speed rear and 3x front. You probably won't get all the clicking out in the big big. And small small might be an issue for other reasons. With a 2x front, you'll still have some clicking in the big big but not usually excessive when trimmed out. Assuming you have STI's and understand trim. Do flat bar shifters have trim? I don't know.

The clicking isn't a big deal. You shouldn't be using the big big for anything more than to get over the steepest section of climb on your ride. Get rid of the clicking completely and you might have issues with chain dropping to the small ring when you don't want it to. I'll take the clicking any day. If it wears something out a few miles sooner, I'll pay to replace it. And that can be a plus since you like to tinker with things.

fietsbob 08-13-20 11:23 AM


Unca_Sam 08-13-20 11:28 AM


Originally Posted by wilson_smyth (Post 21639015)
Ive been adjusting my commuter bike after its first 300+ km.
After tuning the rear derailleur is about 90% but there are a few small things that are niggling me and a few hours of fine tuning has not sorted it.

First off, my methodology was:
- release the cable holding screw/bolt.
- Turn the fine tuner on the derailleur all the way clockwise.
- turn the pedals and push the derailleur to get the chain to the 2nd smallest cog with my hand.
- pull the cable, not too hard but enough to pick up slack and tighten it onto the derailleur.
- starting on the smallest cog, click the changer back one. adjust the fine tune counter clockwise until it changes smoothly with no clicking.
- do this for all cogs.
- if chain is falling off either side or clicking on the biggest or smallest ring, adjust the limit screws.

I followed the process found on the you tube vid "How to Adjust your Shimano Rear Derailleur | #CGT - Bike School" (i cant post links)
Its mostly smooth now except for on the 2nd largest cog, there is slight clicking, if i adjust the fine tuner to get rid of this clicking, the change from the smallest to 2nd smallest ring becomes rough.

The bike is only 3 months old, sparsely used, is almost mollycoddled so gets no abuse outside from a 15-20 mile cycle on clean roads every second day.
Would appreciate any pointers in how to get it the last 10%.

:foo: interesting process, that!

What's served me well goes like this:
  1. With the derailleur mounted and no cable tension, set the high limit. Do that by lining the upper pulley teeth up with the smallest cog teeth. The chain is optional, but should be set to the middle chainring for a triple. Use the largest for a double. This eliminates chainline effects.
  2. Shift your lever to make sure you're in the highest gearing (the cable head will be closest to the housing stop). Turn your barrel adjusters to center them in their adjustment range. Pull the cable tight through the housing and secure tightly but not up to recommended torque. Pull the cable away from the frame, and loosen the pinch bolt to take out any extra slack. Tighten pinch bolt to recommended torque.
  3. Turn the crank and start shifting to the lower gears. Watch the shifts to see that one click lines up with one cog. When you get to your lowest gear, set your low limit per the manufacturer recommendation. IIRC, Shimano recommends your low gear limit be set so that the pulley teeth line up just to the right of the outside face of the largest cog, so you don't throw the derailleur into the spokes.
  4. Shift up and down the cassette and watch for incomplete shifts in the center of the cassette. It's here that you'll use the barrel adjuster to move the derailleur as needed to lock in your index.
  5. Shift to your lowest gear and tighten or loosen the B adjustment screw at the back of the derailleur to move the upper pulley teeth within 5 mm of the largest cog's teeth. This helps your shifts to be precise by limiting the amount of chain deflection between the derailleur and cassette cogs. Ensure that the adjustment doesn't interfere with any other cogs on the cassette.

pdlamb 08-13-20 11:53 AM

You might want to check the derailer hanger isn't bent.

wilson_smyth 08-13-20 01:32 PM


Originally Posted by Iride01 (Post 21639057)
Did you tell us what it is that you need the last 10% of?

If this is a 11 or even 10 speed rear and 3x front. You probably won't get all the clicking out in the big big. And small small might be an issue for other reasons. With a 2x front, you'll still have some clicking in the big big but not usually excessive when trimmed out. Assuming you have STI's and understand trim. Do flat bar shifters have trim? I don't know.

The clicking isn't a big deal. You shouldn't be using the big big for anything more than to get over the steepest section of climb on your ride. Get rid of the clicking completely and you might have issues with chain dropping to the small ring when you don't want it to. I'll take the clicking any day. If it wears something out a few miles sooner, I'll pay to replace it. And that can be a plus since you like to tinker with things.

Apologies, its a 2x11 speed commuter bike with flatbars so the shifters are [color=#223137]Shimano SL-RS700.
I agree that the clicking probably isnt a big deal, but if it had no clicking to begin with, then id like to get it as close to that as possible again.
I do enjoy tinkering, but its aim is to get as close to ideal results as possible for me.



Originally Posted by trailangel[/color
]
Read the directions for adjusting Shimano Rear DR from Shimano.
Take note... adjust high limit screw so top pulley is just outside of smallest sprocket.
Attach the cable correctly to the DR... Attach the cable correctly to the DR... attach the cable....


Thanks for this.


Originally Posted by Unca_Sam (Post 21639074)
  1. Shift your lever to make sure you're in the highest gearing (the cable head will be closest to the housing stop). Turn your barrel adjusters to center them in their adjustment range.

I will try this tomorrow, thank you.


Originally Posted by pdlamb (Post 21639120)
You might want to check the derailer hanger isn't bent.

I am 100% sure it isnt bent.

trailangel 08-13-20 05:32 PM


Originally Posted by wilson_smyth (Post 21639317)
I am 100% sure it isnt bent.

How do you know this?

Dan Burkhart 08-14-20 06:24 AM


Originally Posted by trailangel (Post 21639761)
How do you know this?

Exactly. If I can see that the hanger is bent without the tool, it's really bent. I use the DAG tool on every service and adjustments are frequently necessary , but I would not be able to determine that without the tool in many cases.

70sSanO 08-14-20 08:42 AM


Originally Posted by wilson_smyth (Post 21639015)
Ive been adjusting my commuter bike after its first 300+ km.

So how did it ride for the first 300km?

If it shifted fine for the first 300km, you don’t do anything, except clean and lube.

Typically the cable stretched slightly and it only requires a fine tuning of the barrel adjuster, either on the derailleur (old days) or at the shifter or cable stop.

It sounds like you are going through the process when installing a new derailleur. I didn’t follow your gyrations for adjustment for each cog.

John

wilson_smyth 08-14-20 09:56 AM


Originally Posted by 70sSanO (Post 21640558)
So how did it ride for the first 300km?

If it shifted fine for the first 300km, you don’t do anything, except clean and lube.

Typically the cable stretched slightly and it only requires a fine tuning of the barrel adjuster, either on the derailleur (old days) or at the shifter or cable stop.

It sounds like you are going through the process when installing a new derailleur. I didn’t follow your gyrations for adjustment for each cog.

John

you are not wrong at all! It ran fine, but i was giving it bit of a self service and decided to see if i could improve things. i had been told the derailleur would need adjustment, possibly cable tightening.
It seems i went nuclear on it when it just needed a bit of a twist.
Im not too bothered by it though as it means i learned quite a bit about how gears work, their setup and maintenance.
I intend to do most of my work myself so have to learn at some point!

I had another go at it today using the instructions from shimano and it feels a bit better again. Most of the gears are engaging just before or on the click of the shifter, which is what i was after, that reassuring super quick change that happens on the click of the shifter!

Thanks for the help and advice all!

70sSanO 08-14-20 10:14 AM

Here is an easy trick a friend showed me. Once you get your limit settings correct and have taken the slack out, set the chain the the middle cog position. Turn the barrel clockwise and as you continue to turn it, the chain will want to shift to a lower cog, back it out and turn it counter-clockwise and it will eventually want to shift to a larger cog.

Once you know the range, you can set it in the middle and if it upshifts too slow, turn it a click clockwise, too slow downshifts, counter-clockwise.

The other issue might be bad tolerances on cog spacers. When I’ve broken apart cassettes I’ve measured the thickness of the spacers. Occasionally I’ve found some to be off by more than I would want.

John

zacster 08-14-20 01:35 PM

Park Tool Derailleur Adjustment

I use the above method. I didn't read through all the responses here but I know this one works. And when it didn't for me it was because my spacers were incorrect.


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