As with the Ergo Tre Bibshort, the Ergo Tre short is an update of Castelli's Ergo Due short. If your preference is for a half short with no bib straps, and you're looking for that traditional staple of cycling, the classic eight-panel design, this is as close as you'll get with Castelli; it's more than enough for most.
As with the Velocissimo, and all their shorts, Castelli designers start with the chamois and work from there. As with the Velocissimo, they use Castelli's KISS3 chamois. It is designed to have most of the features of Castelli's Progetto X2 pad, but at a better price. They did this by reducing the number of layers in the pad from three to two. The top layer, called the Skin Care Layer, is a seamless, soft fabric that is backed with 4mm of soft foam. The Cushioning Layer is shaped high-density foam of infinitely varying thicknesses, with smooth transitions from the ultra-thin edges to generous padding under your sit-bones.
The short is made of Affinity Lycra, a "standard" 190g stretch fabric. The bottom of the legs has traditional gel grippers sewn inside the shorts. All the panels are joined with a double-needle cover stitch. There are reflective tabs sewn on the back of the legs.
The Castelli Ergo Tre Short comes in Black. Sizes start at Small and run through 3XL.
I already had a pair of large Castelli bib shorts, so I thought I was pretty clear on sizing. However, these shorts (in large) are both too tight and too short in waist height. I am returning for XL to see if that cures both issues.
Update -- the XL's are OK on fit, I would still prefer shorts like the Sugio RS, when I can find them on sale at comparable prices.
I also had the problem of them being a little low riding to the point that between the castelli jersey and these low riding shorts, I tend to show my belly area when walking/taking a break after rides. Even though I don't have much of a belly to speak of, it's not the nicest look.
That being said, they are very comfortable and have a nice pad.