bikemig 

I'd like to buy a 31.8 dual pull front derailleur in relatively clean condition and decent quality.

It's for a 1992 Trek 950 I am rebuilding. The bike came stock with a bottom pull FD and it routed the cable on a screw that went into the frame. It may originally have had a pulley that has gone MIA. In any case, the spring on the existing FD isn't doing the job with the current set up (it won't go into the little chain ring). I figure I'll clean up the derailleur cable run by going with a top pull FD and a cable stop that will mount to the frame. So I need a used FD to make this work. Most of the current front derailleurs aren't really made for 46/36/26 rings.

So let me know if you have a 31.8 dual pull FD you'd like to sell and for how much.

TenGrainBread 

I might have an early 90s top pull XTR FD at home, never used. I'll check later.

bikemig 

That's fancier than I need but thanks for looking. I liked your build thread on your Trek 950 with drop bars,

Do you still have that bike? Do you remember (or do you know) if there was a pulley where the front derailleur cable wrapped around (pic 2 in my first post)? I think the problems I'm having with the bottom pull FD would likely disappear if I was able to fit a pulley there but the problem solvers pulley is too large (so are all the pulleys I've found).

I *think* that a top mount FD will give me better shifting since the derailleur cable run will be so much cleaner.

TenGrainBread 

I sold the bike about a year and a half ago. I believe it came to me with a somewhat low end top-pull derailleur, which I replaced with a nicer top-pull Deore XT derailleur.

I do still have an early 90s Giant ATX-760 with an FD pulley that I'm not using. I can measure it for you.

rccardr 

That cable run over the screw makes my behind parts pucker. Ouch!
I'd replace that with a sealed bearing for the cable to run over and a couple of washers to keep it in place.

bikemig 

Yeah I don't like it either.



A pulley of some sort would likely solve the problem but the spacing between the stays is too narrow for pretty much any cable pulley currently being sold. There may have been a pulley on there originally but it went MIA before I picked up the bike. I could try to mcgyver something like you suggest but I figure it's just easier going with a top pull FD and this will give me a cleaner cable run.

rccardr 

OK, but if you change your mind let me know. I'm sure I have a couple of miniature sealed bearings that would fit in that space.

bikemig 

I like the idea of doing this on the cheap! I'll send you a PM.

I think I'm going to have to check out a bearing supply place. There are sealed bearings (and sealed bearings with a pulley sleeve that might do the trick).

The dimensions need to be no larger than 15 mm on the outside and 5 mm on the inside.

This would work for example:

https://www.amazon.com/KML-696-2RS-Double-Bearing-FACTORY/dp/B01N927DOV/ref=sr_1_6?keywords=sealed+bearing+5+x+15mm&qid=1571148521&s=hi&sr=1-6-catcorr

Andy_K 

I've got an Alivio and an SLX, both fairly modern (9 speed) and NOS. You'd need a shim for 31.8 but the SLX has one in the box.

noglider 

@bikemig, email me. I think I have one or two. I bought them by mistake. One might even be never-used.

Wilfred Laurier

Not sure if you saw my posts in your other thread, but I am quite certain you have the cable routed incorrectly. The screw in the bottom bracket shell never had a pulley, and was never intended to use as a pulley. The cable housing seats in the cable stop connected to the derailleur, as you have shown it in pictures, but the cable is anchored to the bolt in the BB shell, not to the bolt on the derailleur.

That bolt in the derailleur is only to hold that cable stop on.
My first job, starting in 1990, was at a bike shop that sold Treks, and while I always wondered why they had that unusual set-up (probably to keep the cable clean as it would otherwise run under the BB, and top pull derailleurs weren't common then), but they worked fine when set up properly.

bikemig 

Very cool. Thank you @Willfred Laurier. I'll need to try this. The plate on the FD effectively makes this a top pull? Using the bolt on the frame to anchor the cable makes a heck of a lot more sense than routing the damn cable the way I had it. The spring on the FD is a bit weaker than it should be but it likely is strong enough to work like this.

wesmamyke

Yeah, +1 on using the BB as the cable anchor. Although they can be very fussy about cable tension, and the length of that piece of housing pushing on the derailleur. Especially with index shifting.

Several of that generation FD actually have a spring tension adjuster as well, look for a screw that can be flipped 180 degrees with a flat head.