derailer mystery Fix it, repair it, how do I do it, what's the best part to use, and now: how do I get there?

[pete jr]

I just got a new bike for the lady-friend on craigslist. <a href="http://www.flickr.com/photos/20663772@N07/2429217093/">
</a>
there are some things wrong with it, but for $200, i'm perfectly willing to ask other people for help. apologies in advance if i sound dumb, the bike i ride should make it clear i don't know a thing about bicycle maintenance.

so, shifters are the sti kind, shimano 105 specifically. in addition to the rear one being kind of janky, i'm having trouble getting the front derailer adjusted right. no matter how far i let up on the limit screws, the derailer rubs up against the chain hard when the thing is in top gear. hard enough that it's impossible to shift into it on the road.

limit screws are the only adjustment i know how to make, but i've never dealt with sti before. i have a book here that tells me there is a "feathering" adjustment you can make in the shifter, but not if you're running a triple in front.

so, uh, is there anywhere else i should be looking?

[Rogelio]

Tell us Pete... Where on the dérailleur did he touch you?:

<a href="http://www.flickr.com/photos/clinicblue/sets/72157604802396617/" title="Front Dérailleur by Rogeleo, on Flickr"><img src="http://farm4.static.flickr.com/3254/2453089614_0514bdb0d6.jpg" width="500" height="375" alt="Front Dérailleur"></a>

<a href="http://www.flickr.com/photos/clinicblue/sets/72157604802396617/" title="Front Dérailleur by Rogeleo, on Flickr"><img src="http://farm3.static.flickr.com/2250/2452261109_bace909b41.jpg" width="375" height="500" alt="Front Dérailleur"></a>

<a href="http://www.flickr.com/photos/clinicblue/sets/72157604802396617/" title="Front Dérailleur by Rogeleo, on Flickr"><img src="http://farm3.static.flickr.com/2044/2452261541_9d85a1b589.jpg" width="500" height="375" alt="Front Dérailleur"></a>

[pete jr]

reading back i guess i was too ambiguous.

the chain rubs against the derailer when it's shifted up to the largest chainring. the derailer, uh, chain-moving-thing (chainstay? is that the right word?) actually doesn't extend far out enough to even clear the largest chainring at its smallest point (where the arrow points). the, uh, joint piece that extends out when you shift doesn't seem to want to extend far enough to get the chainstay to clear.

[Rogelio]

So, I think it's called, the cage doesn't reach far enough to clear the largest chainring or it clips with some cage metal against the teeth at the poing of contact?

Have your tried loosening the dérailleur at the clamp and, facing down from the driveside, turn it counter clockwise slightly when you're in top gear? I'd recommend removing loosening the cable before you, if you, try this or it will pull the dérailleur down.

[Stanglor]

That's not a limit screw adjustment, it's a cable length adjustment that is needed. From your description I can't tell if it needs to be tightened or loosened, but you can tell by grabbing the front derailleur cable as it travels down your downtube. Yank on it. If that makes your rubbing problem better then you need to tighten the cable. If that makes it worse...loosen. There should be a barrel adjuster where the housing stops on the way from the shifter to the derailleur. CW will loosen the cable, CCW tighten. If there is not enough travel in the barrel adjuster you need to make your cable length adjustment at the front derailleur. Undo the allen that clamps the cable and tighten or loosen as necessary.

Park tool has a handy site for tips on this sort of thing.
www.parktool.com/repair/

[langston]

are the components all 105 or just the shifters? Some stuff in the shimano line doesn't work well when mixed outside their group. I've had problems specifically with the RSX line, but it's not outside the realm of possibility.

Consider having a mechanic try adjusting the cabling and doing the adjustment? When it doubt, put new cables on it.

Is the front derailleur torqued out of true? somtimes they get kicked out of place. shit might just be worn out, too.

[Rogelio]

Or yeah, if the cable was too loose...

[Rogelio]

[pete jr]

thanks jamie, that sounds like the thing. i knew there was something dumb i wasn't checking before i threw my hands up and said uncle.

and yeah, it's all 105. i checked for that before i bought it, because i have enough half-working bikes in my apartment already:

<a href="http://flickr.com/photos/clango/1075585995/"></a>
<a href="http://www.flickr.com/photos/clango/2452414299/"></a>

[Rogelio]

[Matthew]

[ripper]

[langston]

[Happy Stick Person]

[pete jr]

if you want it it's yours. no joke.

[langston]

[lantius]

[SeditiousCanary]

[langston]

[lantius]

[langston]