Anyone willing to clarify quill stem and bar sizes for me?

Modern bars are 26.4mm or 31.8mm (oversize)

I see NOS Italian quill stems (eg Cinelli XA or 3T Motus) on eBay advertised as 26.0- -can you use a "modern" 26.4 bar in these?

Are all "vintage" bars all the same size--I thought I remembered Cinelli bars as smaller??

Helppp....:mad2:

"Modern" bars are either 26.0 or 31.8. (31.8 is rather new. )
"old school" Cinelli bars were 26.4 (from the 80's & 90's)

Cinelli stems only accept Cinelli or TTT bars. There are a few exceptions but I don't recall what they were.

MR_GRUMPY is correct, with the added caveat that 'modern' Cinelli can be 26.0. 'Old School' is definitely 26.4.

FWIW, the 3TTT stems and bars I have (old school) are 26.0.

The newest stuff I own is 20 years old, so you may safely disregard everything I say. I may be senile.