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Old 02-17-12, 03:55 PM   #1
sen2two
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Big problems while switching gears

I have a 2008 Giant Defy 3 with Shimano sora equipment, which is original. I am pretty sure I need it to be adjusted. I am very much a do-it-your-selfer and I have a backround in mechanics. So with a little instruction from some of you pros, I am sure I can make my shifting much smoother...

Anyone want to help this newbie out here?
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Old 02-17-12, 03:58 PM   #2
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Try taking a look here:

http://www.parktool.com/blog/repair-...nts-derailleur

This will show you how to adjust the rear derailleur, I'm sure there's something similar for adjusting the FD if that's what you need.
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Old 02-17-12, 04:08 PM   #3
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Quote:
Originally Posted by sen2two View Post
I have a 2008 Giant Defy 3 with Shimano sora equipment, which is original. I am pretty sure I need it to be adjusted. I am very much a do-it-your-selfer and I have a backround in mechanics. So with a little instruction from some of you pros, I am sure I can make my shifting much smoother...

Anyone want to help this newbie out here?
If you really are "very much a do-it-your-selfer" You could start by reading the first entry in: http://www.bikeforums.net/showthread...ease-READ-THIS so that you understand how to post something that we can respond to in a helpful manner (rather than "I am pretty sure I need it to be adjusted")

and also checking out: http://www.bikeforums.net/showthread....com-shortcuts

as well as the Park Tool repair instructions at: http://www.parktool.com/blog/repair-help.

It's very unproductive on both sides to come with no real question at all and with no knowledge of how to explain the issue. It is much better to study first so you understand how a particular system, such as the drive train, works. Then you can carefully and methodically attempt to correct the issue. Finally if you hit a snag you can tell us what you have tried and use the proper terms so we understand the problem you are having.

Last edited by cny-bikeman; 02-17-12 at 04:13 PM.
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Old 02-17-12, 04:39 PM   #4
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Try pressing on it hard with your foot.
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Old 02-17-12, 04:56 PM   #5
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Make sure your rear derailleur isn't bent at an odd angle respective to the rear cogs.

You have a rear derailleur. It has 2 screws. H and L-High and Low. The low is the BIG gear/cog. The high is the LITTLE gear cog. I would put the chain on the middle wheel in the front. SHift the rear so its all the way in the highest gear (littlest cog). Adjust the H screw so that the centerline of the pulleys on the derailleur line up with the smallest rear cog. Now shift all the way to the lowest gear (biggest cog). Adjust the L screw so that the centerline of the pulleys on the rear derailleur line up with the largest rear cog. Make sure you can't push the derailleur past that point otherwise you will drop the chain inbetween the spokes and largest cog and bad things happen.

For the front, its pretty much the same except that H and L are reversed. H is the biggest cog and L is the smallest cog.
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Old 02-18-12, 06:38 AM   #6
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try: http://www.youtube.com/results?searc...3.4.1.0.1l11l0 ...... (open in new window) gives several video demo choices on how to do
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Old 02-18-12, 11:50 AM   #7
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Quote:
Originally Posted by bobotech View Post
Make sure your rear derailleur isn't bent at an odd angle respective to the rear cogs.

You have a rear derailleur. It has 2 screws. H and L-High and Low. The low is the BIG gear/cog. The high is the LITTLE gear cog. I would put the chain on the middle wheel in the front. SHift the rear so its all the way in the highest gear (littlest cog). Adjust the H screw so that the centerline of the pulleys on the derailleur line up with the smallest rear cog. Now shift all the way to the lowest gear (biggest cog). Adjust the L screw so that the centerline of the pulleys on the rear derailleur line up with the largest rear cog. Make sure you can't push the derailleur past that point otherwise you will drop the chain inbetween the spokes and largest cog and bad things happen.

For the front, its pretty much the same except that H and L are reversed. H is the biggest cog and L is the smallest cog.
While that's correct, I think that it's still bad advice.

Assuming the limit screws were correctly set when the bike was new, messing with the limit screw adjustment is almost always a bad idea.
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Old 02-18-12, 01:55 PM   #8
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Quote:
Originally Posted by Retro Grouch View Post

Assuming the limit screws were correctly set when the bike was new, messing with the limit screw adjustment is almost always a bad idea.
While I agree with you that messing around with limit screws can cause problems, the converse is also true -- not checking limit screws every time you adjust rear derailleurs is equally if not more dangerous.

Most derailleurs today hold adjustment very well. If a derailleur that used to trim correctly no longer does, there's a reason. It could be as simple as cable stretch (descriptive of effect not cause) and a tweak of the barrel adjuster is all that's needed.

But that's a dangerous assumption because a major cause of loss of trim is the hanger being bent inward (they rarely if ever bend outward). That changes the trim, but also the inner and outer limits, correcting only the trim leaves the bike vulnerable to overshifting beyond the low gear sprocket into the wheel.

My rule --- Every time I adjust trim, especially if trimming the RD outward, I confirm the low gear limit by pulling the cable away from the downtube like a bow string (or pushing the lower body manually in manually) and making sure I cannot overshift into the spokes.

BTW- if low gear limit and trim moved, then so did the high gear limit, and if they moved a lot or slightly a few times, then it's to square up the hanger.
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Old 02-18-12, 02:05 PM   #9
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Since the OP hasn't explained the problem, it's a bit pointless to offer good or bad advice.
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Old 02-18-12, 02:07 PM   #10
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Since the OP hasn't explained the problem, it's a bit pointless to offer good or bad advice.
he got good advice ---- read the available tutorials. the rest is apropos after he's done so.
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Old 02-24-12, 12:12 PM   #11
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Sorry I didnt respond. It's correct that I posted prematurely without doing my research. I also asked a vauge question. Thanks for the helpful hints even though I didnt ask the right question...

I have been reading up and wathcing videos. I want to gain a little more knowledge before I start adjusting anything. I come from the car world where I have built high HP street/drag cars and I have forgotten what it's like to be the rookie. I am not use to having to ask questions.

Thanks for the replys.
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Old 02-24-12, 12:36 PM   #12
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I have Sora on my newest road bike, it may be lower end on the food chain, but once dialed in, it works fairly well. Describe set-up, symptoms, and we will see what we can do to help.
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