Bicycle Mechanics - Chain touching front derailleur after adjustments
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10-19-10, 09:29 AM
I just purchased a used Specialized Allez, its a pretty sweet bike, but it needs a tlc/tune up. I'm trying to do most of the work to educate myself and I'm really enjoying it.
When I first started shifting thru the gears I noticed that the chain was touching the front derailleur when I shifted the rear all the way to the top/inside cog. So, I got out my screwdrivers and started adjusting the front derailleur. I got the clearance I needed I then shifted thru the gears again. Once I shifted to the smallest/outside cog the chain was then touching the front derailleur again.
How do I get the chain free from touching the front derailleur in all gears??
Thanks for any help!
Use the instructions for derailleur adjustments found at www.parktool.com. Do all of the steps in proper sequence leaving nothing out.
If your shifters are STI shoot WD40 into the internal mechanisms of the shifters. This will loosen old hard grease and help remove dirt.
As you shift the rear the angle of the chain coming forward varies. It's usually not possible to accommodate all the angles without moving (trimming) the FD cage slightly. Some systems don't index in front and riders trim as needed, others index but have a trim feature in the form of a second click a hair away from the main one.
If you don't have trim capability, adjust the FD for correct trim in the gears you actually use. Trim the outer position for the outermost and as many as possible rear sprockets (usually about 7 out of 9 or so) and similarly trim the inner chainring for the innermost plus as many as possible.
Don in Austin
10-19-10, 12:11 PM
If you are on big ring front, biggest ring rear, you are "cross-chained." It is not always possible to set up your shifters to avoid rub in the cross-chained positions, depending on how long the chainline is. Adjust the front derailleur for no rub in the non cross-chained combos and use the rubbing noise when cross-chained as a reminder to shift to a better combo.
Don in Austin
Watch this (http://www.ehow.com/video_5774031_fix-cross-chaining-bicycles.html) video.
10-20-10, 05:21 PM
perfect, thanks for the help!
10-21-10, 05:23 PM
hey Al1943, I wanted to ask you after I shoot a little WD40 in my Shimano Sora STI Should I they follow it up with a little lube or just leave the wd40?? They are working pretty good, but I'm itchy to clean them out....not sure why but just want to make sure everything is good and lubed.
Thanks for your time!
I've restored several Shimano STI shifters to good performance by using lots of WD 40. It won't hurt to drop in a little light oil but I don't think it's necessary. And the oil may collect more dirt.
Last week my Record 10-speed left shifter quit after 7 years. WD 40 restored it to excellent performance. I was afraid I would have to buy new shifters. This was the first time I've used WD 40 on Campagnolo shifters and it worked great! I also did the right shifter and it also improved.
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