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Old 10-14-09, 08:55 PM   #1
Unicornz0
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Shimano LX Mega front derailleur, help please.

Hello community, I was fortunate enough to buy a 2000 Specialized Enduro Expert. It does have several problems.. The bike has been sitting for years, and some parts seem to have seized.. In this post Id like help with the Shimano LX Mega front derailleur. It appears to be mounted to a plate on the frame. It will not shift to the smallest chain wheel. I was able to get it to shift to the largest chain wheel once, but not back to the middle chain wheel. There is plenty of spring tension but the FD only moves about 1/8 inch towards the middle chain wheel when downshifting. (It will move about inch past the largest chain wheel with full tension on the FD cable). The FD cable wire is totally slack, and the L adjusting screw is almost turned as far as it will turn counterclockwise without removing it from the FD. Seems like the FD is hitting against a stop or some other obstruction. I dont see where it is being obstructed by anything..
All help is appreciated.
Thanks in advance,
Uni.
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File Type: jpg Shimao LX Mega FD-2.jpg (99.2 KB, 11 views)
File Type: jpg L-Side.jpg (102.9 KB, 6 views)
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Old 10-14-09, 11:17 PM   #2
jacksbike
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If, when the cable is totally slack and the L gear screw is turned counterclockwise up as much as possible, it still does not derail to the smalleset chainwhee., (sorry for all the commas) I think that your only recourse is to possibly bent the steel plate that attaches the derailleur to the bottom bracket. Also make sure that the bottom bracket is tight and that there is no side ot side play in the crankset. Put lots of spray lube on the spring area of the front derailleur to make sure that it is moving freely in and out, too.
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Old 10-14-09, 11:45 PM   #3
Panthers007
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From the look of that cable, I rather would doubt it could move at all. Here is the standard instructions I have as a copy & paste solution for problems, like yours, with the front-derailleur (FD) on a bicycle. Regardless of brand:


Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

http://www.parktool.com/repair/readhowto.asp?id=75

And BicycleTutor:

http://bicycletutor.com/adjust-front-derailer/

When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.

Adding a barrel-adjuster can solve many problems with the cable coming loose - or being too tight.
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Old 10-15-09, 12:11 AM   #4
Unicornz0
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Quote:
Originally Posted by Panthers007 View Post
From the look of that cable, I rather would doubt it could move at all. Here is the standard instructions I have as a copy & paste solution for problems, like yours, with the front-derailleur (FD) on a bicycle. Regardless of brand:
Thanks, but please read my initial post. The cable is in the un-actuated slack position, which would normally allow it to spring back to the inboard position over the smallest chain wheel. Thanks for your comment but please take another look at my post and hopefully you can help.
Thanks again,
Uni
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Old 10-16-09, 06:32 PM   #5
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The derailleur just had serious rust and was frozen. The LBS gave it a good push on the cage and that pushed it over the
small chain wheel. Sprayed it with a penetrating oil made for loosening rusted parts and worked by hand a few times.
and let it sit over night. This morning it was moving freely over all three chain wheels.
Thanks for the help,
Uni
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