Harold74

The front derailleur on this bike as something built into the side of it that strongly suggests a cable clamp into which I'd expect housing to run. However:

1) When I got it, per the photo below, there was no such housing.

2) Coming off of the bottom bracket, there's really no opposing cable clamp. There's just the guide piece screwed on to the bottom.

3) Even if there were housing, the derailleur pinch bolt is not well aligned with the would be cable stop. The cable would just rub against the side of the housing end cap much as it would the cable stop in the absence of the housing.

So my question is this: should there be a housed cable running into this thing? It seem kind of weird but I could install a cable stop at the bottom of the seat tube and get a 5" piece of housing in there I guess. Or do we think that there was never intended to be housing at this location? My concern is that, with the cable rubbing against the cable stop, the metal there is basically sawing away at the cable. I'd be grateful for any advice that anyone has to offer.

What I know of the bike history is this:

4) Two owners before me.

5) Reported to have sat in the garage untouched from 1991 until now. Wear patterns would support this.

6) Last owner tried to redo the cabling for the sale, got frustrated, and gave up part way. What was done wasn't done well.

Hobbiano 

On my '85 610 there's just that plastic guide piece on the bottom bracket and the bare cable. It goes straight from the plastic guide to the cable clamp on the front derailleur. I would see if it doesn't interfere with that cable stop and if you can just bypass it & go straight from the bottom bracket guide piece to the cable clamp on the derailleur. It should be a straight run with no interference. Maybe someone replaced the derailleur at some point.

dddd

The amount of motion that the front derailer cable sees isn't going to wear away anything, and I see plenty of bikes with redundant cable housing stops that contact the cable but do nothing and cause no problem.
I suspect this is just as the bike was first sold, when many front derailers still had housing stops that increasingly served no purpose.

Housings were troublesome in that they trapped dirt and water coming off the front tire, leading to rusted and broken front derailer cables. The current style of open-groove plastic guides took over for good reasons, including reduced weight and SIS compatibility. They improve rear shifting performance even on friction-shifted bikes.

Hobbiano 

Take a look at the 2 photos in post #4 here: https://www.bikeforums.net/classic-v...10-1985-a.html
As dddd says, looks like it came with that setup.

clubman 

Yup, the 86 catalogue says it's a Z -204GS.

Harold74

Thanks for the assistance guys. I wound up taking a stab at it without the housing after all (photo below). The cable kind of cuts across at an angle from the bottom bracket which improves matters some. It seems to work fine for now without excess shifting resistance etc. My wife will likely only be riding this bike for an hour at a time, close to home. So, as long as the derailleur jumping down to the granny ring doesn't trigger a crash, the risks are small.

It doesn't appear that I could bypass the cable stop without modifying the derailleur. That said, I suppose that I could just grind the cable stop off if it winds up being a problem.

When I look closely at the photo below, it seems to me that the cable stop actually has side walls to it at the inside which should help with the wear problem. It also suggests further that this was probably the original FD and the original setup.

If anybody cares to help with the derailleur setup, please see the tail end of this thread which is another of mine: Other Thread

clubman 

If it ain't broke...leave your grinder in the garage Harold.

I don't think another link could come out without stress on the RD

NT86

Nice!

alcjphil

Back when that bike was made, some bikes used a cable guide which clamped onto the downtube at the bottom bracket:
​​​​​​https://www.ebay.ca/itm/233593042009...BoCbNcQAvD_BwE
This allowed the use of a short piece of cable housing that would use the cable stop on your derailleur. Other bikes used the under the bottom bracket cable routing that is found on your bike. Either cable routing works

dddd

I think that the pictured cable path at the binder/anchor bolt isn't quite right here.

Usually there is either a groove in the arm for the cable to pass through, or there is a nub on the arm's face that is toward the non-driveside, and which the cable is supposed to pass OVER (not below the nub)!

Not only might aligning the cable path somewhat correct the rubbing, but on index-shifted front derailers, the cable must be fitted exactly as intended for the leverage to be sufficient and thus for the indexing to work.

Hobbiano 

And something doesn't look right with the clamp around the seat tube. Usually the clamp ears are nearly parallel when the clamp bolt is tightened. I just looked at several of my bikes (including three Miyata touring bikes) and none look like that, and none have that many threads showing beyond the nut.

Mr. 66

I think the cable goes through the pointed part then next to the clinch bolt.

The mounting clamp is thightend more than it should be I probably wouldn't change that unless you need to move or replace the front derailleur.