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Cold is one thing –layer up, ride hard, and you’ll stay pretty comfortable. Cold and wet is another thing entirely, and for that we have to recommend Castelli’s Nanoflex Bib Tights. We haven’t come across another product that keeps us warmer, dryer, and more comfortable when the weather is truly questionable.

The Thermoflex fabric is coated with nanofilaments that give it water resistance. You throw a glass of water on these tights, and the water will bead up and slide right off. Same thing happens out there on the road. The backside of the Thermoflex fabric is a brushed, fleecy-feeling face that traps your body’s heat to keep you warm.

Of course, a pair of bib tights wouldn’t be much with a garbage chamois. Thankfully, Castelli sewed in their venerable KISS3, a low-profile, supportive chamois that will help you stay comfortable throughout base mile season.

  • Thermoflex fabric is water-resistant and insulating
  • KISS3 chamois
  • Mesh bib straps
  • Reviews
  • Q & A

What do you think about this product?

Have questions about this product?

Good, not great

  • Familiarity:I've used it several times
  • Fit:Runs small
  • Size Bought: Large

Obvious bit first, these things run small. For reference, with most brands & our usual teamkit I tend to do either a small or medium jersey & medium bibs. For Castelli, I go large bibs... went with large for these too, but these seem to be a little smaller than even the normal Castelli stuff.

The negative is sorta complex. The material feels good & is usually warm enough, but for bib tights that are aimed at wet(ish) weather, I'd have expected them to be a bit warmer material. It's not that they are overly light, just for something that is aimed at cold + wet, I expected a bit more. Material weight is probably spot on for something like nickers aimed at cool to cold + wet weather, but for tights it just seems like a bit too lightweight - if it's cold enough for full length tights AND wet, these will be a bit lacking.

On the plus side, the thinner material really moves, stretches, bends, & flexes well with no bunching up around the knees or such. Chamois is pretty good too., I'm probably going to really like the knicker version of these.

Good but some reservations.

  • Fit:Runs small
  • Size Bought: XL

Good points

1) Warm down to 39

2) Legs are really waterproof and keep you dry.



Bad points:

1) As others pointed out, they run small—REALLY small. I wear M to L. From previous Castelli bib experience I ordered the XL and they fit well. 5'10" 165 lbs

2) As others also have mentioned, Castelli continues to use lettering that peels of in a short amount of time, even if you hang to dry. Cannondale does the same thing—they need to use something more durable!

3) The seat is NOT waterproof. I'm guessing that water gets pushed/sucked through the seams and soaks the chamois. In the accompanying photo you can see the exterior after a short ROAD ride. I didn't take a shot of the chamois—it looked like I had a case of explosive diarrhea! Lesson learned—next time I'll put the damn fender on!

Good but some reservations.

Great bib, not sized well

  • Familiarity:I've used it several times
  • Fit:Runs small

All my other bibs are L, bought a L and XL to try just in case. Sent both back and got XXL. Love the bibs, warm and comfortable, well made. Bought 2 other brands to try and like these the best by far.

Castelli Nanoflex bib tights

  • Fit:Runs small

Love the tight fit without feeling bound. Very flexible. Medium just fits my 5'9" 132 pound climber build (skinny legs). I have to sit down to pull them on and off because they're so tight around the ankles, but once on, they're perfect. I like that the straps are long enough to not tug on my shoulders. After a 57 mile ride this week in 50 degrees with cold NNW winds, I was thrilled with them. Blocked the cold wind. Comfortable chamois. I've worn them for 3 other rides between 35-50 miles with temps in the low 50s and they're not too warm. I haven't tested them yet below 50 degrees. I pair them with my Castelli Nanoflex shirt, which is my favorite cycling kit piece.

Get it!

  • Familiarity:I've used it once or twice and have initial impressions
  • Fit:True to size
  • Size Bought: XXL

This pants are simply awesome! Could´nt get any better for my use preferences. Must buy in my point of view especially when at sale!
5 stars straight out. I´m 6´3 and 185lbs athletic build

Toasty tights

  • Familiarity:I've used it once or twice and have initial impressions
  • Fit:Runs small
  • Size Bought: L

The tights are as warm as I had hoped. Early winter ride with the temp staring at 36 degrees. My hands were cold, my head was cold, my feet were freezing, but legs and torso were fine. I didn't feel like I sweated in them, even as the temp went up. I thank you, my friends really thank you since these tights replace my Acid Yellow Campy tights, their eyes needed a break

Favorite tights

  • Familiarity:I've put it through the wringer
  • Fit:Runs small
  • Size Bought: M

This is my second pair of nanoflex tights and while they're not quite as warm as the sorpasso wind, they are quite adequate. I love the water repellant qualities of the fabric.

Bottom line: if I had to own only one pair of tights it'd be these hands down.

Typical castelli fit (order a size larger than you would in Pearl izumi or garneau).

Cozy winter rides

  • Familiarity:I've put it through the wringer
  • Fit:Runs small
  • Size Bought: small

I bought these for the hubs (side note - as soon as Castelli offers a women's bib version of these, I'm getting a pair too). Here’s his review:

I’ve never worn tights because I think they're weird, but I live in SLC now and got smacked in the face with truth. There’s a time and a place for everything, and now the Castelli leg-blanket is here to stay. These are exceptionally form fitting and very true to size, but may feel a tad tight if you have calves on the larger side. The fabric goes all the way up passed the navel and does a great job keeping the lower abdominal area warm and shielded. The fabric is not windproof and you may get a bit cooler on a sub-freezing day in the shade, but overall they stay warm. My only small complaints are the side logos are already peeling after just 3 rides.

They fit small

  • Familiarity:I returned this product before using it
  • Fit:Runs small
  • Size Bought: large

I wear a Castelli Free Aero bib short in large but these nano flex came as Large and they are way too small. CC was great about it and they cross shipped a replacement. I hope an XL fits me.

Castelli Nanoflex Bib Tights

  • Familiarity:I've used it once or twice and have initial impressions
  • Fit:True to size
  • Size Bought: medium

I just got these last weekend and last sunday I put in 30 miles wearing them. The temperature was right around 40 degrees when I started and rose to about 47 degrees when I finished. I thought they might not be warm enough as I did my pre-ride checks, but they were fine. The pad and fit was perfect ( I'm 5'9" and about 170 lbs). The tights didn't make me overheat as the sun came out and warmed things up. The straps weren't sloppy, nor were they binding. I hope to get a longer ride in this coming weekend, but my first impression is very good.

Totally awesome...down to 42F and rainy

  • Familiarity:I've put it through the wringer

I wore these every week in the PNW this winter, rain or shine. Did the job very well. Only issue is that on particularly cold and rainy days the knees and thighs start to feel exposed. Riding in 40F weather in soaked conditions was not as fun.

I have not had any issues with lettering falling off, but I never use the dryer for my technical wear. Hang to dry only.

Great on a cold day

  • Familiarity:I've used it several times
  • Fit:Runs small
  • Size Bought: xl

So having the cycling bug is been good and bad. The part that makes the ride the best is really the gear and being dressed for the weather makes all the difference. I am 6'3 and 190lbs (33" x 34" pants) and the XL fits very well. The zippers at the ankles work fine especially over socks. These bibs will keep you warm on rides in the upper 30's - in fact I wore them today, it was 37F and I was warm enough. They also wick the water pretty well, and do keep me pretty dry. So far I love them, I have had them on for about a dozen rides and all is good. One suggestion if you do a lot of cold weather riding is windstopper boxer shorts. Really help in the "man" area. I hope these work as well for you as they do for me.

Castelli runs small: I'm 6'0" 180lbs. 33 waist 33 inseam I ordered XL based on this post and found them to bee too tight. It felt like compression wear. The fabric was overstretched around my thighs, knees and bum. The straps were pulling down into my shoulders. Went with the XXL, which felt much better (fit). I was tempted to get XXXL but then I think it'll be too loose. plus the back and worth was killing me. I have not used them yet.

Update: So I've put them to use in this el nino northeast weather. They are perfect 47 to 65ish. Anything below 47 I need to use more knee protection. I don't own knee warmers so i layer on leg warmers under and its just perfect. I rode in light drizzle and I'm perfectly warm and dry.

Faulty Zipper

  • Familiarity:I've used it once or twice and have initial impressions
  • Fit:True to size

Just bought these last month. They work well but be careful of the zipper. Best to zip them up first then pull them over you shoe covers. The zipper has small teeth and wants to pull apart too easy as mine did. Also, zip them up before putting in the wash. I will order another pair after returning these.

Getting the job done!

  • Familiarity:I've used it several times

I live in Portland area where it rains 10 months a year and these tights are just what I need for most of the time. Nice compression and fit every spot. Completely windproof, haven't tested water protection yet. I don't usually start the ride when it's pouring, but it rains here anytime during the ride, as long as they have good enough water protection to get home, I am okay with it. Chamois is okay, on the edge for 50 miles. I am 5'8" 150#, ordered M first, they were too tight, sent back for a L and they fit nicely with plenty of compression still, just about 1" too long. The only dislike is the Castelli's name printed on both sides of the tights that already started peeling off after a few rides. I don't really care much for these and rather not have them printed on , but come one Castelli! do it right then just leave the prints off. Why made a nice tights and half a$$ job on these. Made in Macau

Exactly - the Castelli print started peeling almost immediately. I finally mercy killed a few letters and just pulled them all the way off. Plus, I'm not a fan of big logos on my glutes. Beyond that, I now have about 1000 winter miles in these, and they do well. Not truly waterproof, but warm enough that in moderate rain I don't feel much discomfort. The pad is good beyond a century (my max in them was 112 miles and they were fine) and the straps don't bother me until about hour 5. So far, the best winter tights I've found. Now if Castelli would just give us a stealth print....

Does What it Says

  • Familiarity:I've used it several times

About 500 miles into Fall in the Pacific NW, and these tights do what they're asked. Completely windproof and - so far - waterproof in a lightweight package. I haven't been caught in a 2 hour Seattle downpour yet, but I have been drizzled on almost continuously for more than an hour and stayed completely dry. I've been using the Gabba top for two years, and its absolutely flawless. These tights are probably not as waterproof, but not bad at all. They're so warm down to about 37-38 degrees F I don't need long wool socks to keep in contact with my extremities. Sizing seems spot on; I wear a medium in all other Castelli products top and bottom, and these (in medium) are almost race fit but not uncomfortable, and breathe well. If you're riding in crap weather, or potentially so, the nanoflex tights are probably your best bet short of bulky, sweaty rain pants.

These look great. I am 6'3 and wear 34 /...

These look great. I am 6'3 and wear 34 / 34 pants. Any idea what size to get? Will a large be too short? Thanks.

I checked the size chart on the Castelli site for you;



Inseams are:



"L" =83cm (approx. 32")

"XL"=84cm (approx. 33")

and a "2XL"= 85cm (approx. 34")



Castelli runs a bit smallish...would suggest the "XL", or the 2XL for inseam length.



Protective booties will offer some protective "gap" coverage, worst case.



Hope this Helps