What an interesting and cool product. The Castelli Cross Sanremo suit fills a critical void in my cycling kit. When it's too cold for traditional kit, but too warm for full winter gear, this suit is the go-to piece of gear.
First, a little about me. I don't actually use this suit for cyclocross at all, I use it for road riding. Also, I tend to get cold very easily. Which is to say, my body cools very effectively. So for me the problem usually isn't staying cool, it's staying warm - especially here in the Pacific North West. Lastly, I've been steadily increasing my enthusiasm for riding suits vs. jersey & bibs. For me and my body type, speed suits are simpler, more comfortable, fit better, and have improved aerodynamics.
In the Pacific North West we have A LOT of days with intermediate temperatures / conditions and I find that 65F in the sun is one thing; 65F with cloud cover, a breeze, and some spiting rain is completely different. Now go hit the road for 3-5-7 hours at 20MPH and the cold becomes intolerable.
The Sanremo Cross suit has a 3/4 length sleeve and a very light fleece lining to the material which adds just enough warmth without causing overheating. The suit makes use of awesome arm pit vents that really work. Next time I plan to use a mesh base layer that I think will help with temperature regulation even more. Other than that, there's not a lot of gizmos to this suit. What makes it so great is the combination of materials and form factor that create a unique piece of gear.
I recently wore this suit on a 125 mile, 15K ft ride over North Cascade Hwy and it was perfect for the conditions. It was in the low 60s and sunny when I started but the weather report showed clouds coming in with a chance of rain. The initial climb was warm and I partially unzipped my top to allow more air flow which was fine (again, mesh base layer would help even more). By the time I hit the pass at 5500ft, temps had dropped into the mid 40s and it started spitting rain. I just added some Thermoflex arm / leg warmers and I was totally comfy. There's just no way I would have been able to finish this ride in traditional cycling gear. Take a look at the attached photo and note the amount of SNOW in the background, I did this ride on June 1st!
How can Castelli improve this suit? Make a version more oriented for road riding vs. cyclocross. The suit comes with the KISS chamois which is good but I'd prefer the Progeto X2 for longer rides. Also, the suit has two large pockets on the back, the traditional three would be better. The arm and leg grippers could be made more aero for road riding as well. These are all nit-picking issues though and I'm glad to have this product available. It works amazingly well considering I'm using the suit in a way it was never intended. I've looked at a lot of suits from many manufacturers and I've never seen anything else like this on the market. I bought another one just to make sure I've always got this base covered.
I'm 185lbs, 6'3 and I wear a size large, which is consistent with all the other Castelli products I own. The suit fits snug without bunching up in the crotch which is sometimes the challenge with speed suits.