Trek Speed Concept WTF?

Any luck with this yet?

You may have solved this already, but I would suspect the bike's compatibility with the tire size. The same size rim can have a slightly different diameter with different tire types. I'd be surprised if your supplier didn't check this, however, as that would be a huge quality control fumble. It is a possibility if you bought the frame and are trying to use your old wheels, but how much contact is being made? Does it rub consistently over the entire tire, prevent movement altogether, or make contact at only a couple of spots?

What I would do:
- Verify wheel is true, wheel sits correctly in rear drops, and box is properly attached
- Continue work with spacers to buy as much height as possible with the box itself
- Consider putting spacers in the rear drops so that the wheel seats further from the bottom of the box

If still an issue, from there I would check with a tri/bike shop for a tire that fits the rims but sits lower for a slightly smaller diameter. If your bike shop can't solve the problem you may consider modifying the box further (shaving the bottom or cutting the connecting points and taping/gluing), but having spent so much on a setup marketed as not needing to be uglied up with that sort of work, I would not be happy about that...

If you solved this already let us know!