How to "un-strangle" a seat tube?

[foxb13]

Hi,

Apologies if there's already a thread on this subject, but since English isn't my mother tongue, I may not have used the right words to describe what I want to do (and find the appropriate thread/solution).

Is it possible to "inflate" a seat tube that has been "strangled" by a front derailleur tightened too much?

I know, I'm not clear :-D So here are pictures of what I'm talking about. The frame is presumably CrMo made with Colombus OR or Vitus Super 983 tubeset.




Thanks!

 

[marc two tone]

Hello, your English is just fine, all very understandable!
That indentation happens alot with Tange ultimate tubing due to its inherent thin walls.
OK, you want to push the dented area back out....I'm an no expert on that subject and access will be exceptionally difficult.

**carefully now**

I've read of filling tube with water, or similar and freeze it, the expansion 'potentially' pushes it out. But how far with an old metal structure with unknown faults....so, forget that stuff for now.

My experience....

Leave it alone and use a plastic shim. My old team marin had some crimping. I bought a 34.9 ----> 28.6mm. Hidden and works well, this prevents the problem getting worse yet, you can carry on riding.