The Annual Tour Sale—New Deals Added Daily »

Castelli Free Aero Race Bib Shorts - Men's


Item # CST005H

Tell us your actual inseam

Note: Actual inseam is not the same as pant inseam.  How to measure

We recommend a size in this bike.

Your inseam: Edit More details

Our size calculator is a starting point for finding the right size for you. To get personal advice talk to one of our fit experts at 1.888.276.7130 or chat now

Select options
  • Select options
  • Black/Black Stitching, S ($199.95)
  • Black/Black Stitching, M ($199.95)
  • Black/Black Stitching, L ($199.95)
  • Black/Black Stitching, XL ($199.95)
  • Black/Black Stitching, XXL ($199.95)
  • Black/Black Stitching, 3XL ($199.95)
  • Black/White Stitching, S ($199.95)
  • Black/White Stitching, M ($199.95)
  • Black/White Stitching, L ($199.95)
  • Black/White Stitching, XL ($199.95)
  • Black/White Stitching, XXL ($199.95)
  • Black/White Stitching, 3XL ($199.95)
  • 100% Guaranteed Returns
  • Free 2-Day Shipping
    on orders over $50

Item # CST005H

It’s all in the name.

Castelli’s Free Aero Race Bib Shorts hide their assets in their name. Namely, free speed, aerodynamics, and race-oriented. The Free Aeros utilize a variety of surface textures, fabrics, and time in the wind tunnel to deliver a claimed 10-watt savings at 50kph. This may not seem like much, but those savings add up over even a two or three hour ride, and could mean the difference between enough power for a sprint and pedaling lamely to the line.

At the core of the shorts sits Castelli’s Progetto X2 Air chamois, with one minor-but-crucial improvement —a softer face fabric. You get all the support and chafing resistance you expect from the Progetto, but it’s a bit kinder to your skin now. We’d be remiss to not mention the lightness of all of the fabrics in the Free Aero Race, in part because they’re comfortable and airy on even the hottest days, but also because you’re going to want to apply a bit of sunscreen at the leg bands.

  • Claimed savings of 10 watts at 50kph due to aerodynamics
  • Progetto X2 Air chamois
  • Giro Air leg bands stay in place without the use of silicone

Tech Specs

race fit
Progetto X2 Air
yes, Carré yolk
Leg Gripper:
Giro Air
Claimed Weight:
[size large] 178 g
Recommended Use:
road cycling
Manufacturer Warranty:
30 days

Size chart


Men's Apparel
Chest 36.2in
Waist 31.5in
Hip 37in
Inseam 31.9in
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.

Reviews & Community

What do you think of the

Castelli Free Aero Race Bib Shorts - Men's

? Share a...

Write a review

No file chosen

Rather attach a photo from another website?

Rather attach a photo from your computer?

    Add a:
  • Share a photo
  • Share a video


Only jpg, jpeg, png, gif or bmp files please.

Submit Cancel

Here's what others have to say...

I have had these bibs for about 2 months and have washed them about 5-6 times. I just noticed that the front of the chamois has become dislocated and partially folded over inside of the outer fabric. What is the warranty and is there any way to get them replaced?

Responded on

I had really good luck with the Castelli warranty department. Chainlove/Steep and Cheap only offer 30 days, but I think that Castelli warranty is 1 year for workmanship problems. You have to send them in, and they will evaluate them and send you a replacement, if it is a workmanship issue.

5 5

Best bib on market!!

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

Best bib ever owned.Fits like a glove.5'8 140LBS and a med fits perfect

5 5

I'll never bother with any other bibs

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

These are my first bibs after many pairs of shorts.
They are easily more comfortable than my best shorts. I first used them in a 75 mi race and they just disappeared. I never gave them a thought, they just sat there and did their job.
The straps are a little snug, but I do have a ridiculously long torso.
I'll never consider any other bibs. They are pricey, but time in the saddle is valuable and these have ruined me for anything lesser.

5 5

Super comfortable, great chamois

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

Update after numerous rides... New favorite bibs, mainly because of GREAT chamois, super comfortable, no chafing after back-to-back 101/65-mile rides in high heat and humidity, just the right amount of padding, etc. New straps, leg bands are different but I found both really comfortable. Redesigned crotch area is MUCH improved. Last year's left no room for the obvious. Now, fit great. Agree with other review - typical Castelli sizing. I'm 5' 8", 155, order a medium. Wish they would do a Skratch Labs color way like offered last year.

Super comfortable, great chamois
5 5

1st ride

Just got these and took them out for an 80 mile ride. I like the fabric on the shorts and the leg band better than the previous year's free aero bibs. I don't think I like the fabric at the top of the straps as much, but all in all I think they are an improvement from last year's model. Typical Castelli sizing. I'm 135 lbs and wear a medium. They fit well but are tight especially around the thighs.

Free Aero Race - dimpled fabric

As the name suggests, the Free Aero Race Shorts are designed to cheat the wind, reducing power output requirements by a claimed 10 watts at 50 kilometers an hour. The secret to these gains lies in how the shorts manage airflow across their multiple boundaries and textures — most obviously via the dimpling across the shorts' outer plane.

Free Aero Race - dimpled fabric

Free Aero Race - back view

The seat and front of the shorts both feature fabrics designed for durability and cooling breathability, respectively, and the entire body is 30% Lycra for a fit that strikes a balance between compression and unrestrictive movement. Castelli also included highly reflective details on the back of the grippers for extra safety.

Free Aero Race - back view

Free Aero bib straps - back

Carré engineered lie-flat bib strap construction for minimal coverage, maximum comfort. Carré is a hem-less strap that lies virtually flat against your skin.

Free Aero bib straps - back

Progetto X2 Air Chamois

The Castelli Free Aero Race bib shorts feature a new softer surface fabric on the updated Progetto X2 Air seatpad. The innovative double V construction on the front keeps everything in place without compressing your stomach.

Progetto X2 Air Chamois

Castelli Free Aero Leg Band

The new Giro Air has the same perfectly flat, stay-in-place grip, but with less mass, which no doubt contributes to the claimed overall weight loss of 17 grams and definitely reduces the aerodynamic footprint.

Castelli Free Aero Leg Band