Castelli Free Aero Race S Bibshort

The Castelli Free Aero Race S Bibshorts are a longstanding design in the Italian brand’s high-performance range, with this the latest iteration. From a quick search I can see that we have reviewed at least four versions since 2013. Designed with WorldTour racing in mind, they offer a mix of aerodynamic fabrics, smart finishing details, and Castelli’s top-tier chamois. However, with a more snug fit than most, it is definitely worth sizing up.

I used these shorts in a variety of conditions, from over 30°C down to around 15 and wet. While they are predominantly going to be used in warmer weather, they are designed for racing rather than specifically for hot weather. That said, I found they wicked sweat impressively well and have no complaints about them for riding in a heatwave. Well, just the one… I found that the Deep Mocha colour I reviewed tended to show moisture more than other colours in my collection. It’s not something I can really hold against the shorts as a whole, but something that’s worth considering if you’re tempted to order. They also come in black, white and Belgian Blue.

Fit and comfort

Castelli is well known for its Italian fit (basically, smaller than you’d expect), and the Free Aero Race S Bibshorts are no exception. The fit is snug and compressive, but without feeling overly restrictive, provided you get the sizing right – I would recommend sizing up, as the mediums that I reviewed were just about on the right side of snug. I have several Castelli bib shorts and these size up smaller than them all.

It’s worth noting, too, that I found a difference in sizing based on colour – the Deep Mocha I was sent in a medium were easier to get into than the rather daring white version I was originally sent, shown here in the photos.

The main panels use a mix of Castelli’s Forza 2 and Vortex fabrics, with the latter appearing on the outer thigh in a dimpled texture that is claimed to improve aerodynamics. While I can’t verify aero gains as the road.cc aero tunnel is still out of order, the shorts do feel slick and fast in use, and the cut allows for full freedom of movement when pedalling hard.

The bib straps are minimal and unobtrusive, using a mesh construction with a raw-cut finish that sits flat and doesn’t dig in. I’ve always found that Castelli straps divide opinion, given how much thinner they are than most, but I like how flat they sit under other layers, even if they have less stretch than some and take a little more fiddling to get them on.

The leg grippers are equally low profile, with a wide elasticated band that holds securely without excessive pressure. There’s no bunching or riding up – they simply stay put.

At the rear Castelli has included a thin mesh panel that wicked well and allowed for good airflow around my back in the heat.

Chamois and on-bike feel

The chamois is Castelli’s Progetto X2 Air Seamless, a two-layer foam design that uses a soft upper with a perforated foam core. It’s among the most comfortable pads I’ve used, especially on longer rides.

It is used in the Premio Black bib shorts that I reviewed a few years ago, and it is still up there with the best available. There’s enough density in the key areas to provide lasting support, but it remains breathable and doesn’t feel bulky. Seam placement around the pad is minimal, and I had no issues with chafing.

Out on the road, the Free Aero Race S Bibshorts feel properly dialled. The fit becomes more forgiving once you’re on the bike and moving, and the fabric offers a supportive, compressive sensation.

Whether I was grinding up long climbs or spinning on flatter terrain, they never felt like they were getting in the way, despite being one of the more snug pairs of bibs I have used.

Build quality and details

Construction is good throughout, with flatlock seams and laser-cut edges adding to the premium feel. After multiple washes and a mix of weather conditions, the bibs still look and feel fresh, with no sagging or signs of wear. The wide leg grippers leave some mild indentation, but never any discomfort. The fabric also offers 50+ UPF protection.

One small but interesting detail is the inclusion of a tiny rear pocket on the bib section, which I assume is a race radio pocket – something I haven’t seen on a pair of bibs in yonks.

Generally across the bibs there are some subtle but lovely detailing that makes them feel premium. Whether it’s the flatlock stitching that is thicker than most, and has been made to become a feature of the shorts rather than just the way they were put together, or the subtle imprinted lines on the side of the legs, they look and feel premium and well designed.

Value

With an RRP of £199, the Free Aero Race S Bibshorts sit firmly in the premium bracket, though not at the very top of the market.

For the money, you get a well-thought-out pair of bib shorts that perform at a high level. They don’t have the kind of groundbreaking material you get on the range-topping versions, but they still offer similar performance and comfort.

They’re slightly less than the Assos Equipe RS Schtradivari Bib Shorts S11 Long that Alex reviewed last year. Those have a chamois that is at least an equal to the Castellis, and the material is slightly more experimental, for £215.

Slightly cheaper – by £4 – are the MAAP Training Bib 3.0, with an RRP of £195, which Nick reckoned are super comfortable but can be too warm in the hottest weather.

Check out our guide to the best cycling bib shorts for more options to keep you comfortable in the saddle.

Conclusion

The Castelli Free Aero Race S Bibshorts are impressive – comfortable and well made, and great for short, hot blasts or longer slogs, with a chamois that I know from experience is comfortable and will last for years.

There are some question marks around the sizing, but I would simply say that if you size up from what you normally use you’re unlikely to have any problems.

Verdict

High-performance aero bib shorts, but you’ll almost certainly need to size up

All the deals displayed on our review pages are pulled from a constantly updating database feed of the best affiliate deals available. The criteria for deciding on what are the best deals is who is offering the lowest, delivered price. In most cases we will be showing the very best deal available online, but sometimes you may be able to find an item cheaper. If you can please feel free to post a link in the comments box below. To find out more about affiliate links on road.cc click here.