Velo Mule

I am looking to add cable guides to an existing vintage frame. I have done this in the past with brass tubing, however, brass tubing that is sold in hobby stores is thin walled, so I want something more substantial. I was thinking of steel brake line tubing, at least for the derailleur cable. Has anyone tried using some sort of locally bought tubing? If so, what did you use? I would also think that it does not actually need a tube. A piece of sheet metal can be bent into a "U" shape to act as cable guide or a piece of wire could be wound as a cable guide as well.

Or should I just spend $4 on parts and $8 on shipping and get something that I don't have to cut and shape?

guy153

Car brake pipes should work pretty well. They are the right size. I nearly used some but my local garage only has copper ones so I just got some premade guides from Ceeway with my next order.

Andrew R Stewart 

K&S also offers stainless steel tubes that are far stronger then the brass is. Whatever you do use leave some windage between the cable/casing and the braze on"s ID. Andy

Velo Mule

Thanks guy153 and Andrew R Stewart . Good point about leaving some room on the inside diameter of the guide. That is one of my concerns with brake line (pipe) . The 3/16" brake line is .188" inside diameter and the derailleur cable housing is .167" . That might not leave enough room for paint and wiggle room installing the cable housing. And if I change the cable housing in the future, it may be a little or a lot bigger.

I make this sample guide from solid copper wire and while it might work, It looks like it would be more difficult than a tube to silver solder on. And I don't really like the look that much.


I might try an art and hobby store and see if they have stainless steel tube. That seems like it would be prefect if they have it. I have mostly seen brass, but perhaps I wasn't looking for stainless in the past so I didn't see it.

unterhausen

I got thinwall stainless from McMaster. Their shipping has doubled since then though, the brake line might be a better idea

pwyg

I have 2’ sections of 1/4” x .020 stainless tubes for sale. They are vastly superior to brass tubes used for this application. They are 5.1 mm i.d.

Velo Mule

PM sent to pwyg . I am also looking at McMaster since the company that I work for buys from them regularly, perhaps I can piggy back onto an order.

Velo Mule

I received the stainless tube from McMaster Carr. It is 1/4" outside diameter, with a .028" wall thickness for a 4.9mm inside diameter. Part number: 89495K775. I plan on cutting the pieces 10mm long.

Fredo76

Are old-style derailleur cable guides that are brazed onto the top of the bottom bracket considered inferior these days? Just curious why you wouldn't use them on a vintage frame...

Andrew R Stewart 

For the factory (or builder) drilling a hole in the bottom of the BB shell to fit an outsourced cable guide is vastly faster, thus cheaper, then brazing on a pair of above guides. There's nothing wrong with above guides if they are well placed. If poorly located the cables can rub on the tubing surfaces though.

If the frame is used and already has the above shell guides then by all means use them and be happy. IIRC the last time I brazed on a set of above guides was in the mid 1980s. Andy (Who has a few pairs in his stash slowly rusting away)

Velo Mule

Actually, I would prefer to uses old style cable guides. I was just too cheap to spend the money for them. This is for an old Lampert bicycle that I put a Sturmey Archer AW hub. It is not special or need to be just right. The stainless tube is cut in pieces now ready to be silver soldered, however, I am still working out some details. I think running the cable on the southern route looks better, down the down tube, under the bottom bracket and along the chain stay. The problem is that if I wear certain fat heal shoes, it hits the cover or the cable. So, I re-routed the cable to the northern route. Along the top tube to the seat cluster and down the seat stay. This keeps the cable from getting "twanged". But I am thinking that in the future I would like to go to a modern Sturmey Archer hub with rotary shifting and if I do that I would go back to the southern route.

The good thing is the old AW is working just fine. There may be no reason to spend more money on a hub, spoke and a rim. The AW is 40 holes, so a new rim would be needed.


Thank you all for commenting. This has been helpful. Hopefully, I'll make up my mind and just get the guides on the frame. I could always take them off if I go with a new hub.

Andrew R Stewart 

Be aware of cable friction when running an AW hub. The spring that the clutch and cable are moved by is not very strong one. Before lined casings became the norm AW cables that had the casing stop on the chain stay suffered more friction issues than those that the stop was on the DT and a pulley served the BB routing angle. I might suggest looking at having the inner cable running through a liner sleeve if you must use a top of shell Campy like guide. Andy

Velo Mule

Good points @Andrew R Stewart , I am using lined cable and having no problems. It is new cable housing and low friction, lined housing. My thought was to line up the cable guides so that the cable would be a straight shot along the top tube and seat stay with the only bends being the transitions. When I was installing the shifter cable it moved easily through the housing. But over time... I will keep that in mind.