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Old 01-28-06, 10:19 PM   #1
karldegoof
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Sora rear derail probs

im only new to the road bike scene (riding for bout 6 months) a=nd have come across probs with my rear derail. after adjusting cable tension i cannot engage the highest gear when using either of my front chainwheels...help please - this is quite annoying
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Old 01-28-06, 10:35 PM   #2
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You probably need to start over from the beginning. Goto the Park tool website, disconnect your shift cable completely, and follow their directions starting at the very beginning. The sequence of the various adjustments that you make is important.
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Old 01-29-06, 09:48 AM   #3
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You've got the cable tension so high that the derailleur won't reach the high limit stop. If it worked before you "adjusted" it, the stop is set correctly but the cable tension and travel are incorrect.

As RG recommended, loosen the cable and start over following Park's directions.
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Old 01-29-06, 10:23 AM   #4
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You get what you pay for.
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Old 01-29-06, 10:45 AM   #5
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Quote:
Originally Posted by ewitz
You get what you pay for.
What kind of a comment is that? Sora isn't the fanciest stuff out there but it certainly works well. Campy Record doesn't shift any better if it isn't adjusted properly.
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Old 01-30-06, 09:53 AM   #6
Don Cook
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Quote:
Originally Posted by HillRider
You've got the cable tension so high that the derailleur won't reach the high limit stop. If it worked before you "adjusted" it, the stop is set correctly but the cable tension and travel are incorrect.

As RG recommended, loosen the cable and start over following Park's directions.
When cable tension is applied to the rear derailleur, it moves the derailleur guide pulley towards the spokes. As you increase tension it moves closer towards the spokes. Eventually, if enough cable tension is applied, the guide pulley moves the chain to that little part of hell between the largest cog and the spokes. Due to how the derailleur is designed to operate, I can't imagine that too much cable tension would "prevent" the derailleur from moving towards the spokes. I can imagine the upper limit screw causing the problem, and I can imagine a chain line that's not parrallel to the bike frame causing something similar, even a damaged/bent derailleur is a possibility. But I respectfully doubt that too much cable tension is the culprit.

Your advice on visiting the park website is great. You can hardly argue with the "read & learn" approach.
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Old 01-30-06, 11:27 AM   #7
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Quote:
Originally Posted by Don Cook
When cable tension is applied to the rear derailleur, it moves the derailleur guide pulley towards the spokes. As you increase tension it moves closer towards the spokes. Eventually, if enough cable tension is applied, the guide pulley moves the chain to that little part of hell between the largest cog and the spokes. Due to how the derailleur is designed to operate, I can't imagine that too much cable tension would "prevent" the derailleur from moving towards the spokes. I can imagine the upper limit screw causing the problem, and I can imagine a chain line that's not parrallel to the bike frame causing something similar, even a damaged/bent derailleur is a possibility. But I respectfully doubt that too much cable tension is the culprit.
That's the problem with using terms like "highest gear". I'd assumed the OP ment the chain wouldn't drop onto the smallest cog which would could also be called the "fastest" or "hardest" gear. Too much cable tension would certainly do that. Your assumption seems to be the opposite. I understand your thought process but my vote's going with Hillrider.
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Old 01-30-06, 01:20 PM   #8
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Don't be put off by unhelpful comments - there is nothing wrong with Sora, I have the miles to prove it

As I believe the earlier replies mentioned, the problem is that the cable adjustment is incorrect, so that the indexing position (the gear selected) at the shifter is out of step with the position of the derailleur on the sprockets by one position. The Parktool website is a very good place to start. This is a pretty easy job to straighten out and is an area that all derailleur bikes require a little bit of attention every now and again.

Heres a quick guide, if things are not too messed up and the two cross-head high and low movement limiting screws on the derailleur have not been adjusted. Note, it helps to look vertically down at the derailleur & sprockets to check their alignment with respect to each other.

Step 1: Shift the shifter until the deraileur is all the way out to the smallest sprocket (run the pedals round to allow things to move) and there are no more clicks i.e. highest gear setting. Dont worry if the derailleur doesn't go all the way but be sure to get all the clicks at the shifter - this is our reference point for the setup.

Step 2: Adjust the the cable's barrel adjuster untill the smallest sprocket can be engaged. If the derailleur won't move, and the cable is noticably slack the adjust the "high" limit adjustment screw until the derailleur allows the chain onto the smallest sproket. Adjust cable tension so that one click of the shifter takes the chain up to the next sprocket. Now we should have Shifter and derailleur on the same setting.

Step 3: Check the shifting up and then down through all gears, one by one, before attempting to ride. Make sure you can get all gears at each respective shifter click. Be sure that the shift to the largest sprocket cannot force the chain off between gears and spokes - this will cause total destruction of the derailleur, as I found out once . If it does, reset the "Low" limit screw on the derailleur body so that the large sprocket can be engaged, but the system cannot move too far to the left.

That description probably makes the process sound harder than it is!

Good luck, hope that helps,

Ed
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Last edited by Ed Holland; 01-30-06 at 01:36 PM.
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