Castelli Free AR 4.1 – Review

Castelli is a name synonymous with style and performance. The Italian company first produced clothing for cyclists way back in 1910, over 100 years ago. Since then they have become one of the most recognisable brands in the sport and have revolutionised how both amateur and professional cyclists dress on the bike.

Take the Gabba, for example, it’s the go-to piece of kit for wet days on the bike. Chances are you own one yourself, if not you probably know someone who does. Castelli were also the first to produce the speedsuit; a piece that offers the aerodynamic advantages of a skinsuit with the versatility and functionality of wearing a jersey and bib shorts.

The new SS18 features some exciting new products as well as some old favourites. The Castelli Free AR 4.1 was a World Tour race jersey just a few years ago but has now been updated to be the ultimate all-round jersey. We got our hands on this re-vamped product, along with the bib shorts, cap and socks to match to review them for ourselves.

Castelli Free AR 4.1 Jersey

a close-up of the castelli free AR 4.1 jersey in red

Velocity dimpled fabric and mesh raw-edge arm grippers.

The Free AR 4.1 was originally the race jersey for the likes of Ryder Hesjedal and Moreno Moser back in 2015 but has since been modified into what it is today – a highly functional jersey that’s perfect for almost any ride. An aero-fit remains but with enough stretch to be extremely comfortable regardless of your shape or size.

We’ve put the jersey through its paces, having tested it in everything from light drizzles sweltering hot conditions. Velocity dimpled fabric on the front panels and shoulders speeds up drying and improves wicking. The Nervato fabric at the armholes has a separate feel entirely to the rest of the jersey and isn’t just there for aesthetics and breathability. The unique material actually aids aerodynamic performance by improving airflow.

It’s common for component manufacturers to back up their claims with wind tunnel data but rarely do we see it from clothing manufacturers. Castelli, however, has shown that the Free AR 4.1 saves 12 watts at 40km/h compared to a normal race-fit jersey. Not a bad bragging right from an all-round jersey with a zippered rear pocket for your keys or spare change.

One of my favourite features are the sleeves, in particular, the length and cuffs. The sleeves don’t extend all the way down to your elbows and the cuff doesn’t feature a super sticky silicone gripper that makes the jersey difficult to pull on. Instead, the ends of the sleeves feature mesh raw-edge arm grippers that keep everything in place but feel as suitable for a training ride as they would in a race.

a close-up of the back of the Castelli Free AR 4.1 jersey in red

Castelli Free Aero Race Bib Shorts

a close up of the castelli free aero race bib shorts

Vortex dimpled fabric for improved aero performance.

For me, bib shorts are not an area worth skimping on. They’re the only thing between your backside and your saddle. The difference between a decent pair of cycling shorts and a fantastic pair may only be £50 but trust me, when you’re five hours into a ride, you’ll be happy you paid a little extra.

The Castelli Free Aero Race bib shorts pack a huge amount of bang for their buck, especially when you consider how reasonably they’re priced compared to the competition. The first Free Race Aero shorts were produced in 2007 and have since undergone continuous improvements in response to feedback from Castelli’s professional teams.

The fit is nothing short of perfect, they really do leave you wondering how so many manufacturers can get it so wrong when Castelli always manage to get it right. Lie-flat bib straps keep the extremely comfortable Progetto X2 chamois firmly in place throughout your ride.

There’s nothing worse than when the legs on a pair of bib shorts start to ride up. GIRO air mesh leg grippers evenly distribute pressure and grip around the leg to ensure this doesn’t happen.While these shorts have been engineered for top-level racing and are worn by the likes of Team Sky, their features make them ideal for whatever your cycling challenge.

a cyclist riding in castelli free aero race bib shorts

Free Cycling Cap

the castelli free cap in red

The Free Cycling Cap from Castelli is 100% cotton and is the perfect clothing accessory, regardless of the season.  It is versatile enough to be worn during the colder months of the year when all you need is a little extra protection from the elements. That being said, it has been engineered primarily for spring/summer and comes in a number of colours to match the Free AR 4.1 jerseys

Free Kit 13 Socks

castelli free socks in red

Are you really a true cyclist if you don’t get excited over a new pair of socks? Generally speaking, white or black socks are most people’s go-to, including myself. In some cases, however, it can be fun to mix things up with your sock game and add a bit of colour.

The Castelli Free Kit 13 socks come in a range of colours that look great when paired with the matching AR 4.1 jersey. As with any piece of cycling clothing from Castelli, their socks do more than just look aesthetically pleasing. Meryl base yarn helps your feet to breathe while you cycle and prevents any funky post-ride smells. A midfoot support band keeps the sock where it needs to be and provides arch support.


The AR 4.1 jersey hasn’t lost its race heritage but has simply been toned down a little. It’s lightweight, aerodynamic and versatile enough to be worn on any ride. The Free Aero Race bib shorts are as at home in the pro-peloton as they are on a gentle summer spin to the local cafe. Finally, the cap and socks both compliment the above well and are quality pieces of clothing.

You would expect to find one or two flaws when reviewing four separate pieces of kit, but the truth is you’d have to be extremely meticulous to find any whatsoever. Once again, Castelli has nailed it.

Shop the full Castelli SS18 collection at ProBikeKit.

Johnny Bowles

Johnny Bowles

Writer and expert