That’s what I meant before, we can’t rely on drawings - we need to check physically.
I’d avoid changing the rear disc, it has an uncommon, proprietary connecting profile, refer to this post Dirty dog brake rotors for details. Usual rotors either don’t fit or have at least to be modified to fit.
I did, back then and another time right now.
(Noticed that the older check was made with 16 inch wheels, these are of course different from 18 inch ones.)
However, I’m sure that it is really close, but the Shimano XT caliper would not touch the spokes.
No idea for the Tektro ones…
Edit:
Meanwhile I’ve thought also again about the mounting angle of the reversed caliper.
I mean the adapter will be much more robust if it would be straight - and not angled.
That seems possible (in my personal imagination) but I need some time to verify that.
Another thing which I forgot to mention before:
Did you notice that the Tektro brake has some interesting features, too?
- Park lock with a little extra lever
- Electric contact for combination with Pedelec