Product Review: Castelli Free Aero Race 4.0 Cycling Bib Shorts

Cycling shorts or Italian lingerie? The first thing I notice is how beautiful these are, the straps sheer lux material. With carefully crafted feel – almost lingerie like. They have an aura to them that says “Panache” or “Italian” depending on your perspective :-). It’s hard to describe in words but in hand it is there.

This is a true summer lighter weight bib short. The Castelli Free Aero race 4.0 Bib Shorts (yes it’s sort of a mouthful) at suggested price of $199, but can be found for around $160. Competes with the likes of Rapha’s bib shorts.

The straps, back and upper are a thin construction with durable edges, they material is designed to breathe and not be noticeable on hot days.

This is a complex garment with many panels – 12, compared with just a handful in less expensive shorts. This indicates care about materials and fit. The main quad panels have a dotted dimple pattern to them, which links to the aero story, creating smooth airflow over the surface. The leg grippers use vertical stripes of red silicone that Castelli have revised a few times. The straps are light weight and appear very breathable.

The design and quality of the chamois or pad relates to the comfort of the garment. This bib short has the Progetto X2 Air seamless seat pad. It’s made from 3 layers, the top layer being super soft and next to the skin. Then a cushioning and finally a perforated viscous pad. Castelli claim this is the highest performance and most comfortable pad. They have used this same design for two years running and found success with proteams and everyday riders. The shorts incorporate a floating pad – the inner pad moves separate to the outer skin layer (see top center of photo below), the pad fits uniquely to each rider and saddle.

Ride Feel

With about 300 miles on the shorts, I got a good feel for how they handled.

  1. The chamois pad is slender and smaller than I am used to. The standard Rapha chamois feels a little bigger, especially at the back near the base of the spine. The Castelli pad doesn’t go as high. The downside is this may feel different dependant on what you are used to. The upside is that on hot and sweaty days. The less material back here being a better thing for evaporation purposes.
  2. The Castelli pad fits great out of the package, no break in period and its very soft to the skin, Castelli have taken care with the top material here. With others, I have been used to a little break in period, 2 or 3 rides – not necessarily a bad thing, just different.
  3. Floating pad – Since the inner pad moves separate to the outer skin layer (see top center of photo above), the pad fits uniquely to each rider and saddle.
  4. The overall fit is slightly compressive through the quads and glutes. I’m used to this, seems to be the default material in mid to higher end bib shorts.
  5. The red leg grippers look different and feel slightly different also. They grip but don’t squeeze like the circumferential bands in other bib shorts, I like that.


I’m 6ft 3 tall and weigh 165lbs – Size L fits perfect. I normally I find bib short straps maybe a touch too short. On these, they are perfect, they seem to have some stretch to them.

More Pictures

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