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CastelliFree Aero Race 4 Kit Bib Short - Men's

Sale 25% OffCurrent price:$149.99 Original price:$199.95

Item # CST00S6

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Item # CST00S6

Free Aero Race 4 Kit Bib Short

The professionals on Team Sky had a heavy influence in the construction of the Free Aero Race 4 Kit Bib Short from Castelli. Although most of the riders agreed the existing Free Bibshort was already pretty well dialed, they did request the addition of a loop on the bib to hold a race radio microphone and one rider wanted his chamois shifted back a touch. Apparently, the racers on Team Sky aren't the only ones who like it, the Free Aero Race Bibshort is Castelli's best-selling short, so when it came time for an update, it only wanted to make subtle changes for the better and nothing too drastic. As far as the "Kit" moniker in the title goes, the only difference we can tell over the standard version is the inclusion of color blocking bands at the leg openings.

First up is a new leg gripper that still features a lie-flat, raw-cut edge but now has vertical silicone stripes to hold it comfortably in place without restricting stretch. Next is a new fabric that allows for better print quality and Castelli updated the seams to improve the fit and looks. It also re-engineered the bib straps with new fabrics and construction so they help you stay cooler, lie flat, and are more durable. Finally, it also receives the updated Progetto X2 Air seamless seat insert featuring one of the softest surfaces we've ever felt in a chamois.

  • Castelli's popular racing bib updated
  • Vortex dimpled fabric on the legs offer an aero boost
  • Forza fabric on inner legs stretches for a perfect fit
  • Stripe mesh engineered minimalist bib construction keeps you cooler
  • Doppio V construction in the front increases support and comfort
  • Flat-lock stitching throughout reduces irritation
  • Progetto X2 Air Seamless chamois offers long ride comfort
  • Giro4 leg gripper elastic provides better grip that's distributed over a larger area

Tech Specs
Material[face fabric] Vortex dimpled fabric, [inner leg] Forza fabric with 38% Lycra content
Seasonspring, summer, fall
ChamoisProgetto X2 Air
Leg GripperGiro4 elastic
Recommended Usegravel, road cycling
Manufacturer Warranty1 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.

What do you think about this product?


>Rating: 5


I've used it several times
True to size
Size Bought
5` 9"
170 lbs

Very comfortable for me. Used it on a couple of 65 mile rides without any problems. 170, 5’9, bought a size medium, perfect fit.

>Rating: 3

Feel Great, but Very Fragile

I've used it several times
Runs small
Size Bought
185 lbs

Keep Velcro away from these shorts, especially in the wash. It will dig into the very sheer cloth the bib straps are made of and tear them. The result are runs, like with women's nylons. They're ruined. I have a new HE washing machine with no agitator, so thought I would be safe, but the 2nd wash there was a small tear, and the 4th or 5th one a huge run. I found my RoadID band wrapped around the straps, so assume that is what ruined them. Too fragile to be practical IMHO. If you want to buy them anyway, wash them in a "Delicates Bag", but even that won't protect them from Velcro, as it will penetrate through the delicates bag. They are very cool on hot days, and I liked the chamois, even though it wasn't the thickest, it floated and resisted wadding up after getting sweat-soaked, which it resisted quite well. Crazy effective chamois for its thickness, although not up to Pearl Isumi's PRO bib short level, still a great choice for a hot day. I loved the high compression on the legs, and the red band at the bottom of the legs for great Viz and a sharp look. The material is also fairly slick against the saddle, which also helps the pad from getting stuck on the nose of the saddle and wadding up, or just dragging against the seat. (using a solid Fazik saddle, Antares IIRC, which are hotter than cut-away saddles in summer) It's tight even when going up a size, but using an XL instead of a Voler L fit great. I appreciated the extra squeeze in the legs on long rides. Maybe if I knew then what I know now I could protect these in the laundry well enough to make them viable, but who knows. I really just think Castelli needs to pick a better fabric. This isn't lingerie, it's cycling gear, and that has to make a reasonable attempt at lasting a year or two at least. Very skeptical this could EVER last that long, no matter what measures are taken. SMH. It COULD have been my fav summer shorts.

Just keep velcro out. I kills thin athletic fabrics. I’ve been doing that for years...

>Rating: 5

First Pair of Bibs

I've used it once or twice and have initial impressions
Runs small
Size Bought
6` 3"
200 lbs

This is my first pair of bibs, and I'm very happy! They do run trim, but fit great.

>Rating: 5

First time Castelli buyer

I've used it once or twice and have initial impressions
Runs small

This season I bought 3 pair of Castelli brand bib shorts and one pair of long pants for winter riding. I find the quality of everything I purchased to be extremely high. I've now worn these bib shorts twice and they are extremely comfortable and fit well. The pad is the best and most comfortable I have ever worn. The product holds up well after washing. I also bought a pair of the top of the line bib shorts and those are fantastic as well. I considered Assos and Rapha, but the pricing at the time was excellent. Also, have seen many in my riding club wear Castelli, so that was a strong recommendation for me. Glad I bought them. As far as sizing, i usually wear a large in Pearl Izumi & Voler and was told to take an XL. The people I dealt with at Competitive Cyclist were right and I'm happy with the XL. So, remember the sizing runs small. Go up one size for the best fit.

>Rating: 5


I've used it several times
Runs small
Size Bought
6` 1"
175 lbs

Quite impressed by these bibs. Castelli's Free Aero Race shorts have always been a favorite and it looks like these will be at the top of the pile in my closet. Materials are excellent - the Progetto X2 Air chamois has padding in all the right places without excess bulk, the main fabric of the legs is compressive yet lightweight (I expect these will breathe well in summer), and the bib straps seem to lay especially well against my body and are once again quite airy. Usually I prefer seamless elastic bibs (like Giordana uses) but I have no complaints here. Even without the dimpled material on the legs I'm not winning races but it certainly makes me feel fast. Some of Castelli's lesser pieces have had occasional quality issues with the sewing of the seams but construction is excellent here. Lastly the leg grippers are wide and unobtrusive and the inseam length is perfect. Once again, the fit is compressive to reduce muscle fatigue in hard efforts or on long days. If you're not familiar with Castelli, in general their apparel runs smaller than American brands and sometimes even a bit smaller than European brands. I wear a large bib in Assos, Giordana, and Pearl Izumi's PRO line, I went up to an XL in this for the strap length as Castelli's straps run short and dig into my shoulders in smaller sizes. The XL's straps are perfect and while I was worried that the body of the bib would be loose and baggy, that's not the case at all due to the compressive material. So if in doubt, size up! The only difference between the Free Aero Race 4 KIT and Free Aero Race 4 is the graphics/logos.