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  • Castelli Omloop Thermal Bib Short - Men's
  • Castelli Omloop Thermal Bib Short - Men's Back
  • Castelli Omloop Thermal Bib Short - Men's Back
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CastelliOmloop Thermal Bib Short - Men's

Temporarily Out Of Stock

Item # CST00DJ

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Fit for a Belgian spring.

No, your eyes aren't deceiving you: the Castelli Men's Omloop Thermal Bib Shorts are purposely longer than typical shorts. The Omloop's unconventional length situates it somewhere between knickers and shorts, paying homage to the challenging mix of conditions that define the early season classic of the same name.

By adding coverage all the way to the knee but not beyond it, Castelli avoids the restrictive fit and feel that often plagues knickers while adding a noticeable amount of warmth. If the conditions you ride through in fall and winter bear any resemblance to Belgium in late February, you'll want to add the Omloop to your drawer.

Castelli constructs the Omloop with Thermoflex, a stretchy, breathable thermal fabric developed to insulate and move with you in the saddle. Inspired by the myriad ways the pros adapt their kit to their liking in the face of difficult weather conditions, the Omloop retains a clean, contoured silhouette that would be at home in a race or on your weekend training ride.

Laser-cut leg hems contribute to its streamlined look, and airy mesh bib straps promise to remain a breathable, unobtrusive addition to your layering system. As the Omloop counts itself among Castelli's top-end pieces, it comes built with the Progetto X2 Air chamois. A carefully constructed mélange of multi-density cushioning, the Progetto X2's minimal shape belies its ability to protect you for the long haul, remaining soft and supple over hours in the saddle.

  • Ride through the cold months in this innovative thermal short
  • Form-fitting silhouette closely follows the body
  • Thermal fabric keeps warm air close to skin while it wicks
  • Longer legs blend the best of knickers and shorts
  • Luxurious chamois provides hours of support and relief
  • Reflective accents help you stand out on dim days
Tech SpecsSize
Tech Specs
Progetto X2 Air
yes, mesh
Recommended Use
Manufacturer Warranty
1 year


Men's Apparel




















































How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
Measure around your natural waistline, keeping the tape a bit loose.
Measure around the fullest part of your body at the top of your legs.
Using pants that fit well, measure the crotch seam to the bottom of the leg.

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Good fit for 36" inseam

  • Familiarity: I've used it several times

I have a 36' pants inseam, 32" waist (60 cm bike) and the M's fit well - to just above the knee - which is nice if it's cold out. (I like snug fitting bib shorts - can't stand the flop-factor) I'm typically a L in Castelli but heeded the reviews that said these run big. I wore these w/ knee + leg warmers for 30 degree ride (in CO - sunny) and was comfortable. They are a bit thinner than PI thermafleece winter bib shorts but have double thick layer junk protection which is good. The pad is comfy and the cut is well designed and snug. I'm thinking about picking up a 2nd pr

Strange cut, okay chamois

  • Familiarity: I've used it once or twice and have initial impressions

Everyone should have some warm bibs, and if you're a Castelli fan with long legs, these would be an excellent option! Personally, I'm not enamored by the chamois, and the cut was a bit too long for my liking. The quality of materials is top notch, and they are warm, but I prefer Assos' Tiburu bibs at the end of the day.

Only for skinny people with long legs

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: Small

After reading reviews, I decided to take a chance on these bibs, but not before doing something I usually don't do...measuring myself and consulting the size chart. Castelli clothing is usually form-fitting in medium for me at just under six feet and 140 pounds. On their size chart I fell at the very top of the small size, so I went for it. After one training ride and one 'cross race, I can say these are the shorts I've been wanting for years. They provide complete coverage of the thighs, right to the top of the knees. The waist and bib portion fit like any other Castelli race gear, even though I bought a small. I think if I had gone with the usual medium I would have had the problem a lot of reviewers had, namely the leg opening landing in some weird place I can only describe as your knee-taint. So they just look like extra long shorts on me, but appearance is not important when talking about being warm and comfortable. Consult the size chart, eat a leaner diet, go vegan if you have to, but get these bibs if you want to wear shorts in cold weather!

Only for skinny people with long legs

Not a fan

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

The length of these bibs are strange. Not your standard bib, yet not long enough to be a knicker. The stop in the middle of my knees. Pretty uncomfortable to ride. The chamois is great, but the length is weird.

New to bibs

  • Familiarity: I've put it through the wringer
  • Fit: True to size

Coming from the mountain side, I was hesitant to try bibs. As the weather has started to cool down i would looking for a warmer option to go under my baggy shorts. I love the longer leg length! I love the Progetto X2 Air chamois. I love the warmth that these provide. They stayed put and allowed me to enjoy my ride without worrying about the placement of my chamois. After giving these several good rides I have decided to pick up a few more pair. I love these!!!!

If you have any questions about this or any other gear shoot me an email at or give me a call at 801-523-4053

Built for taller people

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

This a nice option to add to the collection for some cool weather riding. When its too cool for regular shorts but not quite low enough for knickers or tights, the added length over the knee really does make a difference adding warmth over your quads. The inside of the short is a fuzzy nylon creating amwarm feel. I love the straps - lightweight, thin, and basically nonexistent. Like many other Castelli shorts, the Progetto X2 Air chamois is fantastic. I have used these bibs climbing up and descending canyons on pavement and as a base layer under my mountain bike shorts on dirt. I tend to run a bit cooler than most people and was comfortable down to 45 F on the road all the way up to 65 F on a sunny, dry day. They are very breathable, providing comfort when sweating out intervals up the mountain and facing the cool descend down. Not the best option on the market to prevent rain from reaching your skin. I wear a large in Castelli jackets and tights, these run slightly big. The one negative is the longer fit. The length runs a little below my knee when standing straight up, but it goes unnoticed when riding my bike. The overall fit of the piece leans towards the looser side, especially lower towards the knee. When I use these riding, the longer length doesn’t bother me. It probably adds a little extra warmth. For somebody that is taller and has a bigger build, these shorts will fit perfectly.

Disappointed in the design/fit

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

I was torn between choosing the Giordana G-Shield thermal shorts and the Castelli Omloop. I decided to buy the Omloop because of the promo literature and videos on this product. Well it just didn't work for me and maybe that is because I am a American who is 6 feet, 210 lbs at this point in my life. I thought I should order an XXL consider the way Castelli runs pretty small. I have only had one pair of Castelli shorts sever years ago and quite frankly the shorts fell apart at the junction of the short material and the leg band so I didn't buy another pair until now. I wear a 32 inseam pant and 36 waist

Ok but not great

  • Fit: True to size
  • Size Bought: xxl

Got these to fill in between my Bib knickers and the regular Bibs. They are warmer than my summer bibs but the material by the knees is loose and ends at the top of the knee for me and doesn't do much. Will keep to use down to high 40's-50's but will keep using the Castelli Bib Kinckers for colder rides. Shines don't have much issue and my socks almost meet the knickers. I tried both XL and XXL - kept the larger for torso fit- my other Castelli are XL and fit great

Too Large

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

It may have good features, but if it does not fit correctly, it fully deserves the 1 Star review:

I have been wearing Castelli products for a lot of years, and have gradually gone from their large size shorts down to small as I gradually lost some weight and became leaner.

Castelli has a European fitting, meaning that you typically wear a medium, you should size-up to a Castelli large.

Last year I purchased Castelli knickers (size small) for Autumn/Fall riding and was instantly impressed at the snug compression fit. I now shall be wearing Castelli small sized bib shorts in future, and I already wear their Small jerseys.

Which brings us to the Omloop bib shorts. I ordered the small and when first putting them on, noticed that the shorts went beyond my knees, and were not a snug fit, contrary to the description given by Castelli on Backcountry's website. I thought that maybe there was a production fault in that the wrong labels were put on to the wrong shorts. I contacted Backcountry and they sent out another pair (size small) thinking that maybe there was a fault. The newer pair were similar.

The idea behind the shorts is great, and they keep your thighs warm as they claim to. However, at first I thought that they fitted like a Castelli medium, but when I wore them on the bike for a ride, they felt more like a Castelli large.

This is the first time in many years that Castelli (in my opinion) have gotten their sizing completely wrong. okay, I'm not the tallest, but this is a Castelli small sized bib short that we talking about! I will also be contacting Castelli themselves to give my feedback, as they have offices here in the US and have previously been open to conversations about their gear.

I have more photos showing how the material is ill-fitting and bunches, but it seems that I can only add one photo. Hmmm.

Too Large

Are these cut low enough to pull down for a natural break?

Castelli nailed it

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

I was torn between getting the Nano Lite Pro shorts or this, and decided to pick this because of the better chamois (my Aero Race already has the same one, and it's fantastic) and purported knee coverage. I've been through a recent rain, and find that being wet doesn't feel uncomfortable or cold; giving up the water protection of the nano shorts wasn't a big deal.

Well I don't know if I made the right choice or not, but the Omloop sure is a fantastic choice nonetheless. First off, the length. The shorts extend just over the knee, with a soft fleecy material that keeps in the warmth. It's elastic, but it's a very soft grab. There's a little bit of extra material when standing straight up, but I didn't notice the wind flapping it about when riding. The legs didn't ride up whatsoever.

The fit is surprisingly true. My only other Castelli shorts were the Aero Race, and those were a little on the compressive side. These just like to hug your body in the soft material and feel like a second skin. Same size for both, obviously.

As for warmth, well going by Castelli's website, these are warmer than the nano shorts, given the extra coverage on the knee. I took these out on a windy ~65 degree ride; a bit warm for tights or leg warmers, but perfectly fine for these. Plus, if it gets windier/colder, just slap on the warmers.

Given the flexibility of these shorts, I'd recommend giving these a try. Sure, you might get more wet on those fall rides, but the comfort of the better chamois and knee coverage is a godsend.