Recently bought a late 90's Tomassini Sintesi, steel frame with rear brake cable running inside the top tube. I am going to replace all the cables for the first time, and just wondering: when I pull that rear brake cable out from inside the top tube, is there any trick to getting a new cable back in there? Will it thread right through, or do I have to do something like pulling it through the tube with the old cable? Thanks.

Some have a tube inside connected each end so no problem. My pinarello doesn't so I have to slide a cable sleeve over the raw cable and into the top tube to provide a path to get the new one in every time.
If I lose it it is a bear to fish from hole to hole. Pull yours apart slightly and blow some lube in the hole and see if it comes out the other end.

If there is no inside tube connecting the ends (or if you can not determine this), then attach a thin "pull wire" to the brake cable BEFORE you pull it out. Then attach the new cable to the pull wire when installing it.

I sent Tommasini an email asking about this - will post their reply here if/when they respond. Also see thread about this I started under Classic/Vintage. Thanks!
- Michael

I tackled this problem with my SR Litage frame. Tried all the suggested methods along with a liberal amount of cussing and thoughts of sacrificing a virgin or chicken.

By happenstance, I had the cable stuck down the tube when I started twirling it back and forth between my finger and thumb. To my surprise, it popped out the back end. Tempting fate, I pulled it back out and repeated the process. After several successful repeats, I can only surmise that there is some type of ramp or funnel installed that helps thread the cable through.

See if you can pull the housing back and forth in the top tube. If you can, then you have no issues in just replacing a cable. If you can't, because there is no housing in the TT, it's more fun.

I recently built up a 90's Italian steel frame with internal brake cable routing. It's one of those where the cable and the housing both run through the top tube. Both had been pulled out when i got it.

I took the brake cable and put it in the front opening. In the back end, I put a loop of spare cable. I pushed the first cable till it went through the loop, then I pulled the loop out the hole, bringing with it the other cable.

Sounds easy, but it took a dozen tries.

Next, I fed the new cable housing over the brake cable. It went right through, no muss, no fuss.

So, I guess what I'm saying is, if yours is like mine, DON'T pull both the cable and the housing out!

I'd suggest feeding the new cable (with the original soldered end) through the old housing, then pull the old housing out and feed the new housing over the new cable. Voila! New cable and housing.

Sounds like a great plan Gene - I'll try this, thanks. Still no reply to my email from Tommasini-USA. Will post their answer if they write back.

Another "why didn't I think of that!!!" idea from Henke on the Classic & Vintage board:

"I have a bike with internal routing. When the time comes to change cables, I just remove the seat with post and use my index finger to point the new cable up the hole from inside the toptube. I have never had a problem with this method. Guess you need quite long and slim fingers, though."
https://www.bikeforums.net/classic-vintage/360517-tomassini-questions.html

Unless it is like my Pinarello and the top tube only has a 3/8" hole in each end.
Have to take some thin wire and bend it until I find the hole on the other end.
That's why I slide some cable liner tube over the cable untill it is out of both holes and pull old cable out.
Slide new cable in and remove liner. Done. Been doing this for 20 years with this bike. It works.

Unfortunately for me, on my bike that hole was only big enough to get the very tip of my pinky into it.