Bicycle Mechanics - gear problems, need help
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03-01-08, 06:09 AM
I`we been playing around with bikes for many years now. Started on mountainbikes (dumpster rescue), but is also into vintage (has got a favourite fixie) and lighter bikes and foldingbikes. This means I`we rebuilt many bikes, parts taken "from here and there". This to explain that I am not new to this but not at all an expert.
I`we got a problem with my friends bike. It is a 4-5 yrs old hybrid, used only by her. I tryed to adjust the rear gearshifter. I can make it shift to all cogs, but not all at the same time. That means it can go from 2-7 or from 1-6. I am sure I`we tryed "ewerything", but it is approx 6 months ago so I do not remember details, but I am absolutely sure I tryed the "limiting screws", many times. I am going there tomorrow and would be soo happy for help. We are going to put "albatross" bars and therefor also longer cabels. Wanted to get it right.
My problem is I`we got problems consentrating, and reading alot to learn something is often a problem. Also when I learn something I can forget it before the next time I nedd to do it. This is why I ask here instead of reading about it.. I think this might be a "rapid rise" system or something, maby that is why I do not do this type alot.
03-01-08, 06:52 AM
Sounds like your cable may not have been tight enough. When you install the new cables, make sure your barrel adjusters are not bottomed out and install the cable so that it is tight at the derailleur's relaxed position (whether rapid-rise or not). This should give you enough tension to pull through all the gear positions. You can then use the barrel adjusters to fine tune the position of the derailleur.
03-01-08, 06:30 PM
It sounds like the derailleur/cable is sticking.It wouldn't be the limiting screws because you say it will go in all gears.Are there any kinks in the cable sheathing anywhere or any rust visible on the end of the cable that sticks out from the sheathing?You'll find out when you change the cables for longer ones.:D
When you attach the cable to the derailleur the shifter must be in its lowest position with all of the slack pulled out of the shifter.
03-01-08, 09:58 PM
It's the bent derailleur hanger. It's always the derailleur hanger. I'll bet $500 it's the derailleur hanger. If it's an aluminum bike with a replaceable hanger, go to a dealer and get a new one. If it's a steel bike, go to a shop to get it bent back into its proper shape.
03-01-08, 10:24 PM
It sounds like the "v" key is broken on your keyboard.
03-02-08, 01:11 AM
:)Thank you for reply`s
I`we been thinking about something could be bent. The lady is careful, but things happen. I`we had the derailleur hanger problem on other bikes. Actually I pulled out a "derailleur protector" to put on her bike if she has`nt got one.
Cables and housing: I greased it many times since the problem started years ago, and it is not left out in the rain much, but I`ll keep it in mind.
I`we tryed more and less thigth wire, again and again so I think that is not the problem, at least not that alone.
Is the "v" comment for me? Must be, I`m always unsure if i should use w or v. English is not my motherlanguage you know, I think I am doing quite well:D I told you about learning and forgetting problems, so this is why. Can not waste time using a dictionary all teh time. By the way, did`nt your mother tell you not to make fun of old ladys?:D
03-02-08, 12:03 PM
Does the bike possibly have mismatched shifters/deraileurs?
03-02-08, 01:39 PM
Mismatched could be, but it is the same components it came with from the bikeshop (new). We never changed anything but brakepads. I`we been thinking maybe the shifter is bad quality and worn out? Not used much though, but the only time I had a similar problem was a front shifter. Could only do two crank wheels at a time, big and medium or medium and small. After a long time realised it vas worn out and "sagged back" a bit after being mowed by wire being pulled.
03-02-08, 07:23 PM
What kind of shifters are on it?
03-03-08, 05:04 AM
Shimano, cannot remember exact type. Should have taken a picture. Nakamura hybrid bike.
03-03-08, 05:32 AM
Make sure the limit screws are set properly and that nothing is bent. The cables should be free to move in their housings and the shifters should also operate smoothly.
With a rapid rise the deraileur will default to the biggest cog in the rear when there is no tension but setting it up is the same as a regular deraileur... the only difference is that when the shifter pulls the cable it moves the derailer to a higher gear position (smaller cog) instead of to a lower gear position (bigger cog).
Make sure the barrel adjuster on the derailer is turned out about 4 rotations to allow for adjustments either way as you may need to loosen the cable after it is attached to the derailer.
The shifter must be at the point where it is pulling no cable...
Install the cable and pull it through until it is snug but not tight enough to affect the derailer then tighten it... I check this by feeling the cable where it runs along the chain stay and with a lot of practice, I can almost get the tension to be dead on when I tighten the cable and not have to do many adjustments.
Test the bike to see how it shifts and then adjust the cable tension accordingly... I don't know if this bike has adjusters at the shifters for fine tuning or not...if it doesn't all the adjustments will be done at the derailer with the rear barrel screw.
If it won't move down into it's smallest cog when the shifter is at it's maximum pull I would recheck the limit screw to make sure it is allowing the derailer to move into that bottom position and if that does not work, a little increase in cable tension will probably be needed.
I hope this helps.
03-03-08, 06:37 AM
I agree that the OP should check the barrell adjustment for indexed shifting in addition to the hanger.
barrell for indexed, screws for non-indexed.. at least that's how my 600EX is
03-03-08, 06:41 AM
Bent hanger. Has to be a bent hanger.
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