Classic & Vintage - shimano eagle rear derailleur; kind of stumped

I'm working on an old Columbia beach cruiser for a friend. The rear derailleur, which is a Shimano Eagle, has me somewhat stumped. Ever since I can remember, I've been using Sheldon Brown's trick for getting optimal chain length, which has always worked perfectly for me until now. I've been trying to understand the Eagle's design; why is adjusting barrel is at such a weird angle which is way too close to the rear sprockets and makes you route the cable to the anchor bolt at what looks like such an... uncomfortable angle. Anyway, I'm not sure if there's something wrong with the derailleur or it's just me, but it seems like it's not pivoting forward enough, which is causing the chain to be too tight and not even touching the upper derailleur pulley. The attached picture shows what I am trying to explain. Should I just add a few links to the chain or is this a futile battle? Thanks.

Should I just add a few links to the chain or is this a futile battle? Thanks.

...not sure, but every time I come across an Eagle derailleur, I toss it for something a little better, like an Altus or similar from the same period...

I'm working on an old Columbia beach cruiser for a friend. The rear derailleur, which is a Shimano Eagle, has me somewhat stumped. Ever since I can remember, I've been using Sheldon Brown's trick for getting optimal chain length, which has always worked perfectly for me until now. I've been trying to understand the Eagle's design; why is adjusting barrel is at such a weird angle which is way too close to the rear sprockets and makes you route the cable to the anchor bolt at what looks like such an... uncomfortable angle. Anyway, I'm not sure if there's something wrong with the derailleur or it's just me, but it seems like it's not pivoting forward enough, which is causing the chain to be too tight and not even touching the upper derailleur pulley. The attached picture shows what I am trying to explain. Should I just add a few links to the chain or is this a futile battle?

From your photo, it appears that the derailer is busted/rusted. Either the upper pivot is frozen, or the lower pivot spring is broken. If it's the upper pivot, lubrication might fix it.


...not sure, but every time I come across an Eagle derailleur, I toss it for something a little better, like an Altus or similar from the same period...
Not the same period at all! The Eagle is a mid 1970s unit. It's the same as the Lark, except for the addition of the extra bumper. By 1970s standards, these were FABULOUS shifting derailers, possibly the best available at that time (despite the stigma of low price.)

I don't believe Altus existed before the late '80s or early '90s, in the SIS era.

The Lark/Eagle had a very cool feature of an overload spring on the cable anchor, so you could yank as hard as you wanted on the shifter even when stopped. Not only would it not hurt anything, the derailer would then shift down as soon as you started to pedal.

Sheldon "Lark/Eagle" Fan

Okay, obviously I don't know my Shimano derailleurs too well - a few of the Altus units that I've installed in bikes recently do look to be pretty old though and dare I say older than late '80's like Sheldon says. I do know that my experience with those super old units like the Eagle and Lark have given me nothing but trouble in the past. Maybe I've been unlucky...

The upper pivot (the one attached to the hanger) does move, but as you can see from the picture, that's as far forward as it goes. The lower pivot (attached to the pulleys) also moves without a problem through what I think is its full range of motion. I really feel like the upper should move more. Does anyone know how this derailleur is *supposed* to work?

I think I may have figured it out. The dropout hanger (I'm not sure if that's the correct term, but you know what I mean) is spring-loaded, but it was pivoting the wrong way. There is a small notch preventing the hanger from rotating too far. I believe that whoever owned the bike before me somehow moved the derailleur into a position it was not meant to be in. I used a little elbow grease and was able to move it back into its presumed original position. I have to put on a new chain and try it out today, but I'm very hopeful. Thanks for the help, I'll post again when I'm sure that it works.

I don't believe Altus existed before the late '80s or early '90s, in the SIS era.


Altus deraileurs date back to at least 1980 Schwinn Voyageur 11.8s and Super Letours.
http://buggytexas.com/images/198004.jpg

Thanks for everyone's insight. I did in fact fix it (and it works like every other similar derailleur). Now that I think about it, the drivetrain was pretty b0rked when I took it in. Now it's a beautiful bike and rides like a dream. I almost don't want to give it back.

Everything evens out eventually. Post a pic of the cruiser!

"The Rusty Scupper":

http://flora.mcb.uconn.edu/~andrew/x/img/bikes/scupper-01.jpg