I'm about 5'11" 140 pounds. Should I get a small or medium? The smalls seemed reaaally tight while the mediums were pretty snug. I'm just afraid the smalls would become too small as I'm trying to gain weight this winter.

If the small is too tight and the medium is only "snug", get the medium. Worse comes to worst, you can always stuff a banana in it for compensation

I have two pairs of Castelli bibs. I'm 5'10" 150. Get a medium, trust me. I could almost wear a large. Matter of fact, I probably could.

I'm 5'9" 175 lbs, and read some advice on Castelli before ordering that said to use the size chart from Castelli and go one size up from that. It worked for me, but barely, I got XL bibs and they are snuuug. They keep me from eating too much. Castelli is made for skinny Italians-but I like em.

Whatever your size is in US standards, add one and that's your Italian size. Had a XL pair and needed a XXL after trying them on. Learned my lesson.

I'm not sure why this is even a thread. Get the ones that are pretty snug, not the ones that are reaally tight.

I'm 5'7", 135lbs and wear medium in Castelli. I'm pretty sure I couldn't fit into small. After rides there are seam lines on my thighs for an hour or so afterwards, so I'm thinking about trying a large next time.

I am 6'1" and 157lbs. I have tons of Castelli. Everything from bibs, jerseys, speed suits, sanremo suits to cross suits and I wear a medium. It fits great but I like a tight "race fit" you may not. A large is way too big for me.

i'm 5'7 125 and wear small. I would go medium at your size for sure.

Ok I Guess what I really meant when I said that the smalls were really tight was that they are more of a race fit/compression short. I'm just afraid that I'll grow out of the shorts in a few months but then again I don't want the chamois moving around when I ride in the mediums

I love bib threads.
People are so obsessed over the fit
I am going to scratch a few drawings and numbers on the barnap that is currently sitting under my big glass of Titos rocks and submit it on Shark Tank.
A small chain of custom fitted bib shops.
It would be a license to print money on the 41

I noticed a lot of skinnies here...

I think Castelli has somewhat different fits depending on the range: race fit is almost one size smaller than their regular fit in my experience, so you have to be careful in what you are looking at. Given the info about you, I think a race-fit small may be too short, the shoulder straps will dig in and make you very uncomfortable in the shoulders, it will lift up too much to make the crotch area too tight.

What Castelli bibs are regular fit?

Get the smaller ones and consider it motivation to not gain winter weight.