cyclotoine

I find you have to size down one size with the LHT because they are way longer than anything else on the market in a given size.

To the OP. it may be true that the reach is the same but the height of the bars is not as you point out. How does that affect you arm to torso angle I wonder? I am asking genuinely.

Try this:

sit as if you are on your road bike holding the bars. If you sit up bending only at the waist and keeping your arm to torso angle the same your hands come back. This means to be comfortable you must bring the bars closer to you as you raise them.

So, if the 54cm gives you the same horizontal reach but the bars are higher it will be too long as you should get the 52.