rodri9o

I have an older MASI 'Gran Corsa'. It is a Columbus steel frame with internal top tube routing for the rear brake. The frame was bought new in '95.

I rebuilt it back up for riding and have noticed that where the rear brake cable housing comes out of the rear portion top tube it has begun to creep into the little tube that runs inside the top tube for the internal cable routing, and the rear brake is getting more and more slack (that's how I noticed it, really). Looking in the routing tube running through the top tube, there s a stepped end on each end, the the rear one of kind of beaten up.

So, now, all I can do is drill/file out the step on each end and run cable housing all the way through the tube, or get it repaired/painted which is not in the budget at the moment.

Sticking with opening up the stepped end of the internal routing tube, how can I be sure the cable housing will fit in through the entire length of that internal cable routing tube?

Bob Pringle

One solution might be to run the brake cable external to the top tube using clamp-on cable (housing) stops such as these:

https://www.biketoolsetc.com/index.cg...-on-Cable-Stop

Not the most beautiful solution, but practical and fairly cheap.

Retro Grouch 

I'd think twice before drilling into that internal tube. I'm thinking that pushing cable housing all of the way through through that tube would be HARD..

My first try would be to try to find a stepped cable housing end that matches what's left of your internal tube.

supcom

Run the brake housing along the top tube and secure it with zip ties. It's the rear brake so performance is not critical. When you get some money saved, take it to a frame builder for repair.

Retro Grouch 

That would be my second alternative.

rodri9o

I figured that the little routing tube inside the top tube would be all the same diameter...the brake cable housings go inside that little tube on the enter/exit areas....

But it is a good point to not assume it is I guess. Man...this is driving me nuts!

Boss Moniker

I'm not sure if I'm visualizing the problem correctly, but couldn't you make some kind of ferrule out of plastic or metal that would secure the end of the housing, yet slip inside the frame and be held in place by a flange? Kind of like the housing ends that all bike shops sell, but with the open end flanged so it fits inside the hole in the frame but stays in place.. you'd probably have to tweak it because it's not at a right angle.

rodri9o

the problem is that the rear portion of the brke housing creeps into the internal routing tube with every squeeze of the brakes and pulls the plastic coating off the housing...the wound up portion of the housing works its way into the routing tube.

HillRider

Can you fitted a metal ferrule on the end of the housing? That should protect the housing and keep the plastic coating from creeping.

rodri9o

i will look further...but so far no ferrules fit inside the routing tube, and all step-downs I have tried do not fit snug inside the routing tube.

I think I will follow Boss Moniker's advice: I will make something out of plastic...shave it down and pop it in there to stop the cable housing...a little microscopic 'hockey puck' with a little hole drilled in the middle.

Pictures to come!

rodri9o

Woohoo! I got lucky, I feel.
I went to the shop today (finally!!) and went through the ferrule box...found a stepdown ferrule that fits perfectly inside the top tube routing tube. I wish it were not as exposed, but at least it works and there is no more cable creep!! Seems to be a good solution for the moment...unless I get the frame repaired, which I eventually plan to do, it looks to be the best alternative.

Pictures, as promised:





sorry for the blurry pictures...the light was weak and low batteries don't help.
Thanks for all your helps!!!

Boss Moniker

Hey, that looks very good.. I'm glad it worked out.

Ironically I was converting my funny bike with internal cable routing from its track configuration to its road configuration just yesterday, and for the first time I couldn't get the rear der. cable to get all the way through the chainstay. I'm pretty sure that it doesn't have cabling on the inside, but it might either have a metal guide (tube) or little funnels at either side to help guide it (despite welding new dropouts on it, I still haven't really had a chance to inspect). Twisting the cable helped but not before 30 minutes of frustration.

Internal routing can be a *****. Oh, and if you want that to look better, you could easily grind down the open end of the ferrule, but it no doubt helps orient the housing, and it doesn't look too bad, so I'd keep it.

I'd also love more pics of the entire bike, it looks beautiful.

rodri9o

Yeah....as am I! The next step is to have the same thing in the front portion of the routing tube...so the interface looks the same on the entry and the exit.


I just posted in the Classic and Vintage forum...not sure it qualifies being from '95.
https://www.bikeforums.net/showpost.p...postcount=1616

dvs cycles

I've had to use those ferrules for the 20 +years I've had my 1987 Pinarello. Pinarello never put a tube from hole to hole either. Makes things fun when it's time to change cables. I have to slide some liner tubing over the old cable before removing it so I have a chase back in unless I want to go fishing for a while.