I just wanted to put a warning out there to avoid the Trek AT-550 wheels if at all possible. Mine have had lots of issues but the biggest is that the spokes do not hold up. In the past month alone, I've lost 3 spokes under normal load (under conditions that, according to Trek, they where designed for). Previous bikes I've owned - even cheap Walmart buys - never lost spokes under the same load and riding conditions. I'm not the only one to have these issues either... Ex: Bontrager AT550 wheels are garbage - WhatILearnedAboutCycling's blog (unfortunately the first link Google brought up when I did a search for "at-550 wheel"!).
To make matters worse, the rep I was working with on the issues at Trek/Bontrager just stopped responding for no reason (at least not any that was communicated to me) after asking some questions about the issue. The poor experience with Trek is enough to make me question if my next bike will be a Trek or not.