unterhausen

It's a chain slap protector. It was pretty common on French randonneuring bikes. You can buy them from Compass.

mikeread

I spent quite a while admiring the clever features and top craftmanship on that frame but the chainstay protector looked out of place and a bit naff. Looks like something a barber would have on the wall for stropping his razors :-)

long john

Andrew R Stewart 

I see that the orange bike took enough care to supply a spare tube so that after the top one cracks you can use the spare . Andy

long john

BigPoser

So where on the top tube is the proper area to place the holes for the routing? Closer to the joints are farther away? I would put the entry on the "lower left 45" on the front, and then more in the "upper center-leftish" on the rear; if that makes sense. But how far away from the joints themselves? 2", 4", 6?

Trying to learn. Thanks in advance.

Brandon

Andrew R Stewart 

Since there's some greater possibility for the tube to suffer a crack at the cable port I suggest it's placed in the thick walled section. Perhaps the butt lengths should be figured out WRT to the ports. Andy.

dsaul

There is a series of photos in this Flickr album, showing how I did the internal brake routing on one of my frames. https://www.flickr.com/photos/starrc...57641510596513

unterhausen

I had it in the back of my mind that 1/4" .028 tubing will work for this, but brake housing is 5mm and that means that .026-ish wall tubing is needed. I have seen reference to 7mm tubing, where can I get some of that?

On edit: I see there is 1/4" OD, .2" wall which should work. Wonder if I have any.

wsteve464

I use these guys for SS tubing for internal routing.

https://www.mcmaster.com/catalog/124/172

unterhausen

yeah, I have almost $300 of small parts in my cart at mcmaster right now

That's where I saw you could get 1/4" OD, .020 wall tubing

BigPoser

Thanks for that. What size are the slots you make for the entry and exit points?

dsaul

I'm pretty sure I used a 1/4" center drill to make a hole and then enlarged it with a round file until the tube fit at the necessary angle. Use the file at the angle you want the tube to exit and it goes pretty fast.

I have a milling machine now, so I would use a 1/4" end mill to make a slot and then fine tune the fit with a file.

Its best to practice on a scrap piece of tube to figure out how wide and long to make the slot.

unterhausen

doing it on a practice tube is a good idea. I have a pile of tubes I bought to practice with, have to do this on one of those

mCharlie

Hello there,

Do you think it is doable to Stuff internal routing with a piece of metal and braze it then fill it to get back to a plain tube so you can put external routing ?
The internal routing is made by a tiny tube wich goes in the top tube.

Thank's

Andrew R Stewart 

Sure, one can fill a accessible tube with all kinds of stuff. Calking comes to mind. If you ever wanted to go back to internal routing I suggest thinking about what you use as a plug/filler. Andy

mCharlie

Thank you for your advice. I let you know when I do that.

Brian25

On the older (bonded) aluminum Trek road bikes, they would have a huge hole on the seat tube where the top tube joined, and you would insert a long foam tube into the top tube (after the brake cable was installed) to keep the brake cable housing from making noise.

mstateglfr 

My frame used cable stops and a brass internal guide tube. If there is cable slap inside the tube, I sure cant hear it. Its all brazed together and quite solid. Making the entry and exit ports at an angle(other than at 12oclock. mine are about 7:30) will help reduce the chance of water penetration, as well as the fact that its just an overall snug fit.

BigPoser

Thank you! Do you happen to have a pic of the tubing you run in the top tube? Last night I ran my first brass tubing for the brake cable. It will be for the full housing. It came out really good actually and I thought it was easy. Just took some time to get it right. I can refine the process a bit more though. I was on the fence of running a housing stop set up, but thought I'd give that a go on the next one. I'll take some pictures when I get home today and put them up.

BigPoser

Here are the pics. I got a little silver happy but overall, I'm very pleased.

unterhausen

thanks for posting. I have to do that this week, it's bike building week. Now I'm thinking about retrofitting a frame with this first.

long john

mCharlie

When I see that I doubt that I can remove it and replace it by external routing..
Maybe I must change the whole top tube ?

unterhausen

I don't understand what you're getting at, can you elaborate why would want to remove it?