Like all Castelli, order one size up. 5'11" 155 lbs I order large.
Can't even believe how much better these shorts are than anything else I've ever worn. Great pad that is not spongy and annoyingly thick. Great fit around legs. No bunching or climbing up your thigh or anything weird. Look great, feel great, durable. I'm sponsored by another brand that I have to wear when racing. I wear these when I'm out on my longest rides. Worth every penny.
I am a huge fan of shorts, on hot days especially. These are so much more comfortable than any bibs I've ever had. On winter rides, these will be under my tights.
I have a hard time shopping for bike clothes as I really can't predict what will fit. That said I realized that there are real benefits to a proper fitting jersey that can wick away moisture. I'm 5'9" and 165 lbs and this jersey in a Large fits perfectly. I've gone on up to 100mi rides with it and it has always been comfortable and has done what I needed it to do. I have mostly worn it in 65-80 degree weather, mostly near the coast in the SF Bay Area. It will probably be good for hotter weather as well.
Curiosity, and the anticipation of an excellent product prompted me to buy these riding shorts. Perhaps my expectations were too high, because I did not find where these shorts were any better, or worse than Pearl Izumi shorts-the brand I've been using for several years.
The shorts are very comfortable, and fit well. In regards to the size chart, I disregarded the suggestion to order a larger size. I wear a small, and found the shorts were true to size. My short rides are 30 miles and my longer rides are 50 miles, so I appreciated the padding- the KISS pad delivers on its promise of comfort. My one complaint is the logo on the shorts.
The logo of the lobster looks so cool, it's discreet, but at the same time let's everybody know you are wearing Castelli. No doubt, that is the desired effect. I was disappointed that after three washes (hand washed, and air dried, the logo began to peel off. If consumers are paying for the name Castelli, shouldn't the logo be made to withstand hand washing. In addition, I was very surprised at how the material bleeds. Once again, I hand wash my shorts, and I've not seen that type of bleeding in my Pearl Izumi shorts.
In short, the shorts are a good product, but you are paying for the name. I hope this information has been helpful.