Last night, I rode home from work with about 3 months worth of plastic and glass recyclables.
All of my day's stuff on the drive side rack of the Transport, all the recyclables on the non-drive side rack. The bag was heavy, about 25 pounds or so (March and April was kind of crappy - lots of bottles), and it caused the bike to want to tip over on the double legged kickstand. Riding, not bad at all - didn't feel like there was too much flex at all in the backend. I think that all the worry about the bike not handling well loaded up was so far unwarented. We'll see in the long run. Do wish that Trek provided a second set of clevis pins for the back of the fold down racks, would provide some more support and cut down on the rattling.