Only worn once in the rain and kept reasonably dry. These seem to be a nano flex version of the Lightweight 2 bibtight. They are not that warm, but are meant to be worn when working hard. The design is a little odd. The warmer material is in the thigh and rear of the lower leg. The more water resistant material is on the front and on the knee. While this is where you want the water resistant material, it is also where you want warmth as it is in the wind. The Lightweight 2 tight is better in this regard as the warmer material covers the knee. Like the Lightweight 2 the pad is fitted slightly further back than corresponding bib shorts. The best thing about the tights is the lack of zip at the ankle. You are likely to wear overshoes without tights and multiple zips get in the way. The tights are tight enough at the ankle to stay in place. I prefer the Lightweight 2 tights, but these are a little bit warmer as the material is slightly more wind resistant and much more water resistant. There is a reasonable size race radio pocket, (which is unlikely to be useful to anyone but pros). I would use these on any tempo ride, particularly if it was wet. If it was really cold I would reach for the nano flex shorts and leg warmers which would double up the thickness of the material on the thigh. I would happily use on a winter chain gang ride or even an early season crit if it was wet. Sizing is similar to other Castelli shorts and tights. These are the race fit and so slightly tighter at the waste. I am 178cm, 31 inch waist, 72kg+ at this time of year and the medium is a good fit.

I've worn these between 5-12°C and few times now. They are rated down to 2°C but I think you would need to be at Zone 4 HR to feel warm; I think 5°C is lowest I would go when at Zone 3 HR. They fit fantastically- I'm 179cm, 95cm chest, waist 84cm, hips 98cm. Size guide says I could get into an M, but having bought some leg warmers, Pro Seamless Castelli, which has a size chart based on weight- I bought L/XL as I am at the top of that size guide 79Kg. They are a little tight around the thigh. The length of these are perfect. I find the Nano Flex stretch from just above the knee to the ankle warmer than the Nano Flex 3G. Even though it is lightly brushed compared to the upper and back of the legs with the 3G it is significantly more windproof- try the blow method through the material almost no air goes through the Nano Flex. For this reason at 5°C I found my thighs a little cold. Road spray is held off well by the Nano Flex. Pad is comfortable- did an 8 hour ride with just a little bit of soreness on the sitbones at the end of the ride. Originally I wasn't fond of the amount of seams around the knee area and the seam found here between the two materials meeting but they haven't irritated me at all when riding- just left marks on my legs at the end. I have a pair of Alè Speedfondo Plus R-EV1 Bibtights which have a seam bypassing the knee and is also flatlocked. So I expected Castelli to put some flatlocked seams in. Straps are comfy but quite plasticky compared to most bib straps.