rothenfield1

Hello BF, it's been quite a while since I've posted since I gave-up my hobby of restoring old steel frames years ago. However, when my wife found this 92 Trek 930 MTB at the Goodwill, I thought it would be fun to dust-off the old tools and boxes of parts to do what I used to avidly do; strip the bike to it's frame, clean & rebuild replacing parts as needed. The appeared to be intact before I began to disassemble it. I ended up replacinng the derailleurs, shifters, cranks, brakes, handle bars, cables, and bought some commuter-type slicks. After rebuildinng the hubs & BB, everything seemed to be coming together nicely until I ran the front D cable and had to scratch my head. There was no braze-on or cable hanger to secure the housing coming off the top tube, and since the FD has to be pulled down so the cable has to come up from the BB somewhere, but there was no way to do it. So I Bubba'd it together by putting a spacer on a screw behind the BB that held some sort of chain maintainer plate in order to round the cable upward and attached a cable router to the seat tube. It works, but it sure looks goofy! Does anyone know what I'm missing here?

stumpjumper2076

It looks like you installed a bottom pull front derailleur and what you need is a top pull front derailleur .

Jeff Wills

I think you're missing a pulley. Someone who knows "vintage" Treks can probably help, but if you can't find an original, you can use one of these:

https://www.universalcycles.com/shop...&category=1613
https://www.universalcycles.com/shop...&category=1613

rothenfield1

The original FD was also a down pull type. The idea of the pulley is a good one, although it doesn't appear that that was the way the cable was originally run. Also, unless it's missing a seat clamp cable hanger or some other missing part, there is nothing to hold the cable housing when it comes off the rear of the top tube.

Jeff Wills

Oh, wait, that's right...

The front derailleur had a housing stop attached to the arm. The cable housing ran from the stop on the top tube and terminated at the derailleur. The cable continued down and was anchored at the bolt on the bottom bracket.

Roth- you need to find the original front derailleur. Those stops were only available for a year or two.

Zef

Your FD is not original. The original spec was for a LX 400 FD.

The bolt behind your BB that you have the cable wrapped around is actually the FD cable anchor bolt. The anchor bolt on the OEM FD was removed and fitted with an adapter to accept the cable housing. The housing would flow from the toptube to the FD, then the cable would continue to the bolt behind the BB. The lever arm of the FD would be actuated by the housing pushing down on it.

Interesting that the 1992 catalog considered this a "Top Pull" front derailleur:
https://www.vintage-trek.com/images/t...ikecatalog.pdf


There is a 1990's Trek Single Tracks group on Facebook with plenty of pictures. I would wager that one of that a group member over there could advise you on restoring your 930.

-j

dsbrantjr

More like a "Top Push"...

The pulley routing idea should work fine with the existing derailleur if true-to-original is not a requirement.

wesmamyke

I probably have an extra one of those F-derailleur mounted housing stops or a derailleur with one if you need it.

Zef

The proper piece you need to make this work if you were doing a restoration job is this:


Not sure if this one would work as it is a different design but perhaps you fabricate and adapter plate for it:
https://www.hoosierbicyclesupply.com/...using-stop-nos


-j

fietsbob

there were a few setups where the Housing pushed down the Upper arm of a bottom pull FD from the top .

and the cable was anchored to the BBshell with a screw .. My 80's Nishiki Alien elevated chainstay MTB was one that did That...

rothenfield1

How wonderful to receive so many responses This is not an restoration. I have the OE Exage 400 LX FD and it does have the housing stop of which you speak, although I'm having a hard time envisioning how the FD would move not by the cable but by the housing?

That's a bit of a problem...I replaced the FD because the OE crank rings are chewed up so I replaced the crank, but it is a little wider then the original and the D wouldn't quite reach so I replaced it. So...I could replace the rings on the original crank and try this "housing push" system or try a pulley and maybe try to find one of those "U" shaped cable guides that hang off the seat post clamp. Yall have answered my original question which is that I thought I was missing an important doo-dad, but still not seeing how the housing alone would have enough torque to "push" the FD.

(As a side-note, what happened to Tom?)

Ronsonic 

A clamp-on cable stop and that Problem solver pulley would sort this out quickly and for not much money. That's how I'd approach it.

fietsbob

8 x 1 & you dont need a FD at all.. Or build a Dual Drive rear wheel the triple moves into the Hub..

Its a Newtonian thing .. like equal and opposite force ...


same thing with the top mount interruptor brake levers

fix the cable spread the housing and cable is relatively shorter..

Bezalel

Either replace the chainrings on your original crank or get a shorter BB spindle (or cartridge) for the new crank.

seedsbelize 

Suntour top-normal fds work the same way, except that the housing pushes up from below. Difficult to wrap the head around, but the shifting is the crispest I've experienced.

bikeman715

(As a side-note, what happened to Tom?) , Tom pass away a few months back , He is and will be miss .

rothenfield1

I believe I will take the path of least resistance, this one.

Although, I would like to see the original set-up in action.

Thanks all, mystery solved.-J