Brake Disc Thickness

I'd make that 4.075mm.

Beware some chinese discs may have a different minimum thickness so as new but not per OE item.

 

These might be OEM fitment for the Street Triple R or Daytona which had the lighter disc rotors which were only 4mm thick when new.
It’s possible these will bolt onto some of the later WC range, but without the matching callipers probably something that’s not recommended.

 

No.
It's a few years since I used old world verniers as all mine have been digital for as far back as I care to remember. If you look at the four graduations the corresponding line is only just out of alignment ( assuming negligible parallax) so the answer is a smidge over 4 and not nearly 5.

I'd misread the top scale with them being grouped in 2's so I'd say it was 4.015 mm.

Old verniers were always a little confusing and as the eyes get older become more of an eye test device than a measuring instrument.

 

Don't know if you can make any sense of my photo for explanation?
You need a bit more of the top most scale for full detail but the difference is miniscule, so it's 4 + 0 + .14 and a bit so about 4.015

 

I read your caliper and gather 4.06mm...at least that is what reads to me

or 4.04mm depends how the angle...

 

Looking again with a more sober head .....
I think I have sussed it although it is confusing as you said.
Is the caliper Metric AND Imperial.
4.04mm reads about right on the bottom scales which equates to 159 thou on the top scales

So this, if brand new, is a 4mm thick disc within a manufacturing tolerance

If you are not looking for a 4.mm disc due to model or age etc then I'd just walk away. Some discs thicknesses vary with manufacturer and anything with up to say 5.5mm is quite possible within the same set up.

 

@TonyG you got me and so out of curiosity I've just been and measured my Brembo discs which are on a late 2018 765rs.

Using a micrometer not vernier (variable as we knew them ) caliper so as to avoid any wear step, they measure 4.46mm.
They are stamped 4.0mm min. thk.

If the ones advertised truly are unused then I can only presume in conclusion that they are factory rejects ........ unless someone has tried to refurbish them to sell on "as new"

Be careful swapping about and ensure the offset remains the same. My Sunstar 675 discs have a different offset to my Brembo 765 ones.