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Serotta
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Discussion Starter · #1 ·
Recently painted frame added new rear centaur 12/27 cog & derailer with a double crank & front changer. Adjustment went as expected, question is I had moved the gear from this bike in the spring to a centurion frame needed a different front changer due to different size of seat tube the gear was the same as I just adjusted Centaur. On the gear I had moved had trouble getting chain to move to largest rear cog, the only way I could figure was to use the cable adjuster on the rear derailer. The set up I just did this was not an issue exact same gear all centaur ten speed.
Is there a obvious reason for this. This makes third bike I have set up this way & was the easiest, mostly. Had same problem with that same gear when it was new?
 

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Matnlely Dregaend
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If it isn't the limit screws, your cable tension may be off. In the smallest sprocket, there should not be a lot of tension on the cable.
 

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Serotta
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Discussion Starter · #5 ·
If it isn't the limit screws, your cable tension may be off. In the smallest sprocket, there should not be a lot of tension on the cable.
The centurion which jumps a cog in the upper rear has no tension in the smallest sprocket. The new set up that works fine, not road tested has tension on the smallest sprocket.
 

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Adorable Furry Hombre
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The centurion which jumps a cog in the upper rear has no tension in the smallest sprocket. The new set up that works fine, not road tested has tension on the smallest sprocket.
If there's no cable tension, and a gear is being skipped....your indexing barrels still need adjusting.

When you transplanted your transmission, you did cut new housing and cables....didn't you?
 

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Serotta
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Discussion Starter · #7 ·
If there's no cable tension, and a gear is being skipped....your indexing barrels still need adjusting.

When you transplanted your transmission, you did cut new housing and cables....didn't you?
Yes new cable & housings, er I think so. I know I had a couple cables left over so the transmission cables maybe not. Moved shifters with rear changer. The housing had to recut.
 

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Sticky cable? That can cause a problem if you have to loosen the barrel adjuster to compensate.

If the cable or housing was taken from the old bike this could be the problem??

To check:-

does the rear derailer move quickly to the next gear when you press the thumb button? In particular, "squeeze" the thumb button between thumb and first finger very slowly to make a "bad" shift. Try to make the derailer spring "do the work" and pull the cable through the housing, not your thumb pushing on the button. Does the derailer always move quickly to the next gear? For all the gears?

Or...

Shift from gear 4 to gear 5, look at position of derailer compared to cog. Is it perfectly in line? Is the chain quiet when you turn the crank? Then shift from 5 to 6 then back to 5. Does the derailer go back to exactly the same position? Is the chain still quiet? Try with some other gears.
 

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Serotta
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Discussion Starter · #9 ·
I did not adj cable since spring, I took out the slack.
Shifts between 4th & 5th good I adj cable tension some for fourth cog.
It now jumps from 1st to 3rd cog skipping the 2nd cog & rough at the bottom cog.
The rest upper seems fine. It has shifted a couple of times from jumping second to top or second to bottom I noticed but ignored. Evidently.
Also adj H screw shifts well except for bottom.?
 

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Difficult to solve this problem without seeing the bike.

If you look at the rear derailer, does it exactly line up with each of the 10 gears?

I would:-

* check the chain is within Campagnolo's specification for wear, or just replace the chain anyway (I had this problem once with a very worn chain)

* check the cassette for wear, do all the teeth look new?

* check the rear derailer hanger alignment (if the frame has been painted, it is possible the hanger has been bent)

* replace the cable and housing to the rear derailer. Use new parts. You don't have to use Campagnolo cables & housings, I use Jagwire or Transfil.

* disconnect the cable from the rear derailer and check you can push the rear derailer across all 10 gears using your hand, and check the limit screws are set properly

* adjust the H screw according to the Campagnolo instructions (I don't think the H screw affects shifting much, but it is worth checking)
 

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Serotta
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Discussion Starter · #11 ·
I
Difficult to solve this problem without seeing the bike.

If you look at the rear derailer, does it exactly line up with each of the 10 gears?

I would:-

* check the chain is within Campagnolo's specification for wear, or just replace the chain anyway (I had this problem once with a very worn chain)

* check the cassette for wear, do all the teeth look new?

* check the rear derailer hanger alignment (if the frame has been painted, it is possible the hanger has been bent)

* replace the cable and housing to the rear derailer. Use new parts. You don't have to use Campagnolo cables & housings, I use Jagwire or Transfil.

* disconnect the cable from the rear derailer and check you can push the rear derailer across all 10 gears using your hand, and check the limit screws are set properly

* adjust the H screw according to the Campagnolo instructions (I don't think the H screw affects shifting much, but it is worth checking)
The running gear was used for two years of light use before shifting to the centurion frame. The cable housings were changed for shifters not the cable.
Is there a trick to get the cable thru the dog leg in the housing without kinking?
The frame did have to be aligned properly for correct angle of derailer, the dropout.

I just took apart the derailer & cleaned everything including getting the wheels in the right places. Adjusted the tension screw for cog 4/5 the H screw for shifts.
The chain & cogs are in good shape best can tell.
The second gear that is almost like the small sprocket does get skipped most shifts.
So maybe a cable change is next.
But otherwise is working better.
The previous install I let the lbs do the adjustment, this time I need to learn.
I will admit I am still learning to adj these things & slowly learning!
 

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I
The chain & cogs are in good shape best can tell.
It's really hard to tell what shape the chain is in. You need to do the proper measurement as defined by Campagnolo. That needs an accurate measuring tool. My chains do about 5000 km before replacement, but it depends a lot on lubrication and the riding conditions. Could be much more, could be much less.

I gave you some tests a few days ago which will help tell if the cable is sticking.

I would buy a few Transfil gear cables (make sure they are Campagnolo and not Shimano), and a few metres of Jagwire LEX 4 mm cable housing, you can buy it by the metre from eBay. Total cost = not much. Then I would spend a few hours really learning how to cut housing, shape it in smooth curves and get it best for your frame. If you damage or kink a cable or housing, throw it away and use a new one. You may make a few mistakes, but it's a cheap way to learn.

I would also measure the chain wear properly, or just replace it. They are not expensive. KMC chains are OK, I think Campagnolo are a bit better, but they are more difficult to install.
 

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Serotta
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Discussion Starter · #13 ·
Thanks I think I measured that chain last winter to be just above spec.
But will do again. I do not have a speedo for bike but would put miles at under 2, K
Up till now all cables housing were Campagnolo, thanks for the alternative.
Housing was changed, as you said hard to diagnose my lack of experience.
Installing all new gear on the other frame that was painted got my attention as to how it should work.
Presently chain is just jumping over second cog most times. 12/27 .
 

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If your chain was "just above" last winter then it probably needs replacement anyway. I would not bother to measure it, I would just replace it.

Watch how the RD moves when you press the thumb button. It should move quickly to the next cog, even if you press the thumb button badly, or if you are pedalling very slowly. For all 10 cogs.

Don't spend so much time looking at the RD that you crash!!!!
 

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Discussion Starter · #15 ·
I used the below method to check the chain, it is within spec.
Not sure what I used last winter but chain has had limited usage until this year.
First couple of years had health issues that slowed things down.
Then last year an accident caused me to move the parts to the centurion frame that was shimano. So I now have two bike set up the same.
I check the shifting in the garage, when I can.

A chain typically lasts between 2,000 miles and 5,000 miles, depending on the conditions of use and on the frequency and quality of maintenance operations. Use a high preci- sion caliper gauge to measure, in different points of the chain, the length as indicated in fig. 1. If even one of the measurement is longer than 132.60 mm the chain must immediately be replaced.
 

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Discussion Starter · #16 ·
Both bikes are set up with centaur gearing both bikes had the odd jump over the second smallest sprocket in the rear. I had inadvertently adjusted the Centurion to jump off the tallest sprocket in the rear, of which this gave a reference as to where the cable adj. was.
After I had backed off on the cable adjuster everything else just worked as it should.
Setting up the fourth & fifth sprocket alignment just has been hit or mostly miss. So it would seem.
Now if I can replicate that on the Serotta?
 
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