Castelli claims up to 15-watt savings with new aero jersey and shorts

The new aero range is said to be the fastest ever from the Italian brand which remains Team Sky's partner for their last year in the pro peloton in their current guise


Castelli has updated its aero jersey and shorts, named now as the Aero Race 6.0 jersey and Aero Race 4.0 shorts, claiming an amazing 15-watt aero improvement when compared to the 2018 version that Team Sky raced during last season.

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The Italian brand, which dates back to around 1876, first produced an aero jersey back in 2006 which first aired with Saunier Duval-Prodir, before Castelli teamed up with Cervélo Test Team in 2009.

Castelli claimed the gains back then meant that riding in its aero jersey on the tops was faster than riding in the drops position with a baggy jersey. It claimed that the Cervélo test team gave up six watts due to sponsors needing to be added to the jersey and instead of the 18 watt aero gain, settled for 12 watts to please sponsors.

Castelli claims its new 2019 jersey and shorts will save three watts at 40km/h and 15 watts at 50km/h compared to its 2018 jersey and short combination.

This advance in aerodynamic efficiency is down to CFD testing, according to Castelli, which pointed to new seam placements and construction as well as elbow length laser cut sleeves. This jersey still feels lightweight and on our scales for a medium weighs 109 grams, which is very competitive.

For the shorts, Castelli's Steve Smith says that the fourth major update to the new Castelli Aero Race 4.0 bib short has been 12 years in the making and "has millions of kilometres of development".

New vertical silicon grippers don't effect the lycra stretch for comfort and security and being laser cut, aids an aero and clean finish. This is teamed with a new panel construction for better fit and support around the legs, bum and lower back and Castelli has added a dimpled design around the legs for enhanced aero benefit.


Dimples in the shorts helps aerodynamics

The shorts have an updated pad too which has a seamless construction to offer less abrasion against the skin. The Progetto X2 is teamed with the Kiss Air 2 pad for increased dampening whilst still keeping that minimalistic feel of the Castelli pad on previous models.

As with the jersey you'll get a lightweight short at 176 grams from a medium.

The ride

I travelled to Mallorca to see Castelli at the end of 2018 to try out the new kit in slightly warmer climes. The first thing to note is that the new Castelli kit follows the classic Italian sizing and is truly race fit. I tested a medium short and jersey, which fitted well, despite my own unfit make-up at the moment!


Trying out the kit in the mountains of Mallorca in December

The shorts fitted very well around the legs thanks to the newly updated laser cut ends with the vertical silicone grippers. Although they managed to help the rather lengthy short remain in place, these grippers didn't feel restrictive or pull on my rather hairy out-of-season legs.

I wasn't totally keen on the pad, although it was comfortable, it's something I can't fully comment on yet having been on a saddle and bike that I don't normally ride. In saying that, it did stay planted in place and its cushion claim does ring true.

The jersey has a great feel to it, and again very hugging to help its performance aerodynamically. The sleeves are mighty long and stop just short of the elbow. A low cut collar doesn't interfere with the neck at all and the waist doesn't cut in at all. The pockets are a decent size with limited sag when filled. This is usually a downside to a lighter-weight jersey.

So far so good for the new kit from Castelli. A longer term test will of course grace our website soon.

Price: Aero Race 6.0 jersey £110, Aero Race 4.0 bib shorts £150.

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Symon Lewis joined Cycling Weekly as an Editorial Assistant in 2010, he went on to become a Tech Writer in 2014 before being promoted to Tech Editor in 2015 before taking on a role managing Video and Tech in 2019. Lewis discovered cycling via Herne Hill Velodrome, where he was renowned for his prolific performances, and spent two years as a coach at the South London velodrome.