Peugeot Dolomites SLX tubing question

[OutlawGeek]

I have this pretty one frameset and I can't find answer to question about seatpost size.
There is 26.6mm but the sticker on downtube says that there is Columbus SLX tubing.
What the cause of this? French size or mix of tubes? I know that Reynolds 531 for Peugeot was in odd size too, 26.4 as far as I remember.

 

[Midlife]

Were the tubes a different size for larger frames?

Shaun

 

[OutlawGeek]

Were the tubes a different size for larger frames?

Shaun

Don't think so, SLX tubeset usually have 27.2 seatpost size without dependence of frame size.