Gear change problem

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  #1  
Old 11-01-03, 09:05 PM
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Unhappy Gear change problem

After changing the tire on a bike I had just gotten I tried riding it, but didn't get far. Every few feet it clicks and feels like it is trying to change gears, but it either doesn't, the chain jams, or the chain gets thrown off the back gear thingy.
What does it seem like my problem is? How easy is it to fix? If I take it to a repair shop about how much are they likely to charge?

Thanks for your help.
 
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  #2  
Old 11-03-03, 10:13 AM
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Join Date: Nov 2002
Location: Northern Virginia
Posts: 640
Cable stretch

You mentioned that you just got the bike- did you get it new from a dealer? If the bike is fairly new then the derailleur cable may have stretched a little, and de-tuned the shifter. A bicycle works by maintaining a balance between springs (in the derailleur, the part that moves the chain from one gear to another) and tension in the cable. As the cable breaks in, it stretches and upsets that balance. You may have noticed that your hand brakes squeeze in toward the handlebar a little further than they used to- same deal with the brake cables.

If you got your bike from a bike shop they *probably* included a free tune-up to take care of exactly that problem. Otherwise, you can adjust this yourself by tracing the cable that extends from the shifter to the derailleur. The cable enters the derailleur through a little knob, which has knurls on it to give better finger grip. By turning that knob 1/4 turn at a time and experimenting a little, you can tune it pretty quickly.

Hope this helps!
 
  #3  
Old 11-05-03, 03:47 PM
las
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Shifting needs set up

Well It looks like your shifting hasn't been set up
I presume you have an Indexed system cause with friction shifting you would of solved the problem.Probably what needs to be done Is let some cable out the rear end of the derailluer turn your barrel adjuster counter clock wise a bit..so when you tighten things up you can adjust your barrel adjuster to get the shifting right on
You may have to take the bicycle to a experienced person
 
  #4  
Old 11-06-03, 09:21 AM
CampyGuy
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if the problem really started when you removed the wheel, are you sure you put it back on correctly? if the azel isn't aligned correctly in the frame, and the bolts or quick release isn't tight you can get a sort of auto shifting problem because the gears aren't where they should be.

try loosening the numts or opening the QR, pull the wheel all the way into the frame, and close the attachment (if it's a quick release it should leave a mark on your hand, that's how you know it's tight enough). make sure the derailleur is over the gear the chain is in, and give it a try. otherwise, it's either have someone do it, or learn to adjust the cables yourself. as uasual parktool.com, click on "repair help"
 
  #5  
Old 11-07-03, 11:03 AM
IoTifoTafi
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Lightbulb "Gear Change Problem"

Someone had mentioned that the wheel may have been installed incorrectly. You probably want to let the weight of the bike center the wheel in the dropouts (the things that hold the wheel.) If that's not it, there are two possibilities. The dropout is bent. This should be taken to a shop to fix (let them break your frame...) It it's not the bent dropout theory, then I think it would be the setting of the "extreme screws." There are two screws on the rear derailleur that control how far the shifting can go to the far left and far right. If these screws are adjusted too far out, the chain will be thrown into the wheel/spokes or get stuck in-between the gears and the dropout. You can do this yourself by hanging the bike on a stand; and, while turning the crank over, watch how the upper derailluer pully (the top gear inside the derailleur) is aligned with the far-gears (biggest & smallest gears.) If it is not aligned, you want to adjust the screws to align those two things (the upper derailluer pulley and each of the two ends of the rear gears.) If you do not understand this, take your bike to a professional racing shop... ie: a "pro road shop." It can cost any where from $3 to $20, because some just charge to touch the bike while others think they're really great mechanics and charge a lot but this seems like it can be a quick/inexpensive fix. Hope this helps. If you plan to do this yourself, Shimano.com may have some information on their website on how the alignment should be of the derailleur and rear gears... the same for Campagnolo.com.
NOTE: Shimano derailleurs don't always align correctly like Campagnolo, so (if you have Shimano) just listen to the sound of the chain to hear if the chain is making any skipping related noises.
ALSO: Make sure the slack in the rear shifting cable is completely let out. This ensures that the alignment will be correct with respect to the adjustment of the screws, and not the tension that is in the cable.
Good Luck.
Io Tifo Andrea Tafi!
 
  #6  
Old 11-09-03, 06:26 AM
Precision Pedal
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Gear change problem

For a "Do it yourself" fic ptobably the most thorough explanation of how to adjust a rear der. is here.http://www.parktool.com/repair_help/...tml#drivetrain
Of course the advice on the correct wheel palcement is a valid point.
 
  #7  
Old 08-09-04, 12:02 PM
wotbus
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Before you go making loads of adjustments back track on what you did. Did it work ok before you removed/replaced the wheel? If the answer is yes then the replacement did'nt go as it should. Try removing it and replacing it again ensuring it is correctly aligned in the frame and the spindle fully seated in the dropouts. BEFORE you test ride it ask someone to hold the back wheel off the ground and gently turn the pedal forwards and check for correct "chain run". Good luck.
 
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