zeropoint

No matter what I do, my Derailleur rubs my chain on my Specialized Crosstrail Sport when I am near either end of the gears. Adjusting the Derailleur does not seem to help. It seems like the Derailleur is actually not pushed out far enough from the frame. Does adjusting cable tension have an effect on this? Any other advice?

Thanks

fietsbob

STI brifters? they do that in the bad - cross chain combinations, even when properly adjusted.

avoid those combinations, they are in overlapping ratio ranges anyhow.

Al1943

More information needed. How many chainrings in front, how many cogs in back? Which brand of components? Road bike or mountain bike? Group name?

Drew Eckhardt 

While the narrower cage width needed to avoid dropping the chain precludes having rub-free operation in one indexed position for each ring, most front shifters (including Shimano STI) have some sort of trim option so you can avoid that (I use Campagnolo and couldn't elucidate on Shimano shifter operation).

onespeedbiker

First let’s assume you know how to set the limit screws; if you don’t check out this site https://www.parktool.com/blog/repair-...ur-adjustments
To get the maximum swing from a front derailleur the cable should have little to no slack when you have shifted to the small chainring. Shimano front shifters also have trim clicks which moves the front derailleur (approx) half a shift up when in the small chainring and half a shift down when in the large chainring. If however, you did not shift past the lower trim click when setting the cable tension, the front derailleur will not shift correctly. Your problem could be improper derailleur swing limit adjustments, too much slack in the derailleur cable, not shifting past the trim click when setting the cable tension or some combination of all three.

zeropoint

Thanks for the replies all, I have already learned a bunch.

The bike is a Womans 2010 Specialized Arial Sport.
The Front Derailleur in question is a Shimano FDM-191, 31.8mm clamp, top-swing, dual-pull.
The crankset is a SR Suntour, 8-speed, the
The cassette is a Shimano 8-speed, 11-32t

The rub occurs in too many gear combinations to mention. It's almost as though the Derailleur itself is positioned too close to the frame.

I have attempted to set the set the stops in all different sports of combinations but this has little to no effect. I'll look into the other suggestions given so far but if this info helps any, please lemme know.

Thanks!

Al1943

According to Amazon: https://www.amazon.com/Shimano-Altus-.../dp/B003COI472, this is a 7-speed mountain type front derailleur designed to work with 48-38-28 chainrings on a 47.5 - 50 mm chainline.

My recommendation is to check the bike's chainline, frame's center plane to center of the middle chainring.
This is largely dependent on the bottom bracket spindle length. Be sure the BB is torqued to specs. Some adjustments to the chainline may be possible, but first measure the chainline. Read the discussion on chainline at www.sheldonbrown.com.

If the chainline is within specs the derailleur(s) should be adjusted according to instructions found at www.parktool.com. It is important that every step is done in sequence leaving nothing out. These are essentially the same as Shimano's instructions. Inspect both front and rear derailleurs for possible bends or other damage prior to making the adjustments.

onespeedbiker

Okay, first question; Is your bike a Specialized Crosstrail Sport or a Woman's 2010 Specialized Arial Sport. Also, has it ever worked before or is the bike new to you? And do you know how to set the front derailleur stop so the derailleur sets farther from the frame? Again, if the front derailleur has any slack in it's lowest position it will not swing out as far. Futher if the outside stop is set too close, the cage it will also stop the cage from swinging out far enough.

zeropoint

Thanks everyone. It turns out that the derailleur is actually broken. A buddy took a look. The part which connects it to the frame is cracked and thus the positioning is out of whack... Thanks again.