Barcon cable stops
 

One of my bikes has bar end shifters, and the down tube has actual shifter bosses on the frame and the shifter cables terminate into something like this:
https://cimg8.ibsrv.net/gimg/bikefor...88acfedca.jpeg
I’d like to put barcons on another bike, but that one has no shifter bosses on the down tube. Can I use something like this?
https://cimg3.ibsrv.net/gimg/bikefor...e9048e796.jpeg
Or will the shifter cables coming off the handlebar now constantly rub on the head stem with the lower piece?

Yes, almost certainly. Put something sacrificial on the endangered location, like a bit of electrical tape, and plan to refresh it when needed. I got lucky, the common red electrical tape matches my bike perfectly. This may also be a suitable application for "helicopter tape", which I see mentioned here to protect chain stay paint but I haven't used.

FWIW, some new steel frames have stops brazed on to the headtube, right where you can expect rubbing. I haven't seen bolt-on head tube stops. It think nobody has come up with a reasonably unobtrusive design yet, but somebody may.

oldschoolbike

there are other options for cable stops..

Search: Vintage Suntour Cable Guide Barcon Housing Stop Down Tube Clamp On 28.6 SUN TOUR
or: Vintage Shimano 333 Dual Cable Down Tube Clamp On Barcon Housing Stop 28.6 mm
Co-Ops usually have several of these stashed away....
and there will also be Huret, Simplex, and Campagnolo options too, i'd venture...
these were mostly used for Stem mounted shifter bikes, but then Bar ends came into vogue... my second road bike had bar end shifters, and the needed stops clamp too... 1970.
Sometimes, i still reach for the bar end while riding my drop bar CF Brifter bike.

Many use a clamp-on Shifter boss with the Adjustable cable stops shown in your post, too. ;)

measure your downtube to verify tube diameter before purchasing any clamps.

If your shifters are indexed, you want the cable stops with barrel adjusters like in your top photo.

All great and helpful replies. Thank you!

You don't need cable adjusters, and if you want them you also use the inline types that float on the housing. There's a cable adjuster on the derailleur.

If you want to avoid rubs, route the left shifter to the right side of the downtube and vice versa. Then cross the wires as they travel under the downtube. Very common.

How would that work? Do you make bigger loops as they come off the handlebar then?
Here’s my one 720 with the frame bosses that hold the cable stops.
https://cimg9.ibsrv.net/gimg/bikefor...048752e33.jpeg

It works just like your rear brake cable is supposed to work - crosses over to the other side for a more gentle curve. That's odd the way you did that.

https://cimg8.ibsrv.net/gimg/bikefor...f023a84acb.png
Check out post #9:
https://www.bikeforums.net/classic-v...er-cables.html

Is there also a different type of brake lever where the cable doesn’t go out the top, but allows you to conceal it under the handlebar tape?

No.

I was talking about your decision to run the rear brake cable on the right side of the headset instead of the normal way.

Yes, Google "aero brake lever"

That rear brake cable wants to go under the handlebar and to the left of the stem (to the right as we're looking at it in that front-on photo).

Yes, "aero" levers, but traditional levers have better cable routing, aero levers require tighter bends in the cable.

So? Is it like any bike with aero levers in the last 40 years had bad brake feel because of them?

I guess you mean the head tube, not the stem. Preferably size the cable so it's only just touching the head tube in the straight ahead position, then stick on some rub-resistant transparent patches like these to protect the paint (or you can just buy "helicopter tape" and cut it to shape/size yourself).

If you are using that clamp on cable stop, another way to prevent cables rubbing on the head tube, is to have the two cables cross each other just behind the head tube, but before they go into the cable stops.
Obviously you would have to mount the clamp with the cable stops on top.

That's a great idea! Someone should bring that up in the thread.

This was from the linked thread, pic by Dave the Golden Boy. I’ll get aerobrake levers with gum hoods and clean everything up like this:
https://cimg3.ibsrv.net/gimg/bikefor...8b3954c8d.jpeg

Not everyone likes having the barcon cables routed up the drops like that.

I wouldn't argue about it, aero levers tidy the cockpit and properly routed cables work fine. I have aero levers on one bike from when I was messing around with some ideas for tri bars. But they're not necessarily an improvement over non-aero levers, and can look out of place on an older bike.

That might reduce rub but it won't easily prevent it altogether.
That depends very much on whether the cables go under or over the bottom bracket. While most modern bikes go under, many older bikes have over-bracket braze-ons (and many more used clamp-on guides that put the cable on top).

If one uses the standard chrome side of the tube stops instead of that aluminum monstrosity it serves both types of routing okay - but you may have an issue with bottle cages. It's easy enough to figure out, though.

If you started riding before aero brakes were common you wouldn't think twice about having the gear cables exposed, because that's the smoothest route which gives the lightest most positive action. Once you start prioritising a clean handlebar you accept a sub-optimal route because it's still good enough.

If one uses the standard chrome side of the tube stops instead of that aluminum monstrosity it serves both types of routing okay - but you may have an issue with bottle cages. It's easy enough to figure out, though.

I found the old style chromed steel double stops weren't easily available in reasonable quality, except used or for inflated NOS prices. Those aluminium stops are ugly as anything but easy to CNC.