Mech Disk Brake Hell (My fault)

[si_c]

I used cable disc brakes for a long while, very good braking is easy to achieve, sometimes too good, been a while since I got rear wheel lift off since swapping to hydraulics.

 

[andrew_s]

Sounds more like the brake caliper is passing the end of the cam (or whatever mechanism it has) before sufficient clamping force is being generated?

This is the problem.

It became a known issue with the Tekro Lyra some years back, particularly with one model of bike (can't remember which, but not the OP's) that had had off-brand discs fitted that were a bit thinner than the Tekro discs.
Ideally, you'd have the brake set up so that the pads are close enough to the disc that the caliper arm doesn't move too far before the pads grip.
If the arm moves too far before the pads start to grip, you may be able to pull the cam over the end, losing braking until you let go of the brake lever and pull again, less hard.