What's Cool In Road Cycling

Castelli Aero Race 5.1 Jersey & Inferno Bibshorts Review

The Aero Race 5.1 jersey and Inferno bib shorts from Castelli offer light weight, high breathability, and form & fabrics designed to save real watts of energy… they’re also damn well suited to a spin class. Here’s why…

AERO RACE 5.1  JERSEY – US$179.99
My quick search for “Aero Race 5.1 jersey” turned up the usual pages full of results, all from either Castelli or retailers, which means this could be the first media review posted on what Castelli says this is the most aerodynamic jersey they’ve ever made. Sadly, the PEZ tech budget doesn’t allow for as much wind tunnel access as we’d like, so I’ll focus on things like fit and fabrics.

But for what it’s worth, Castelli’s lead product guy, Steve Smith, told me this jersey is 24 watts faster than their Team jersey at 50km hour, from tests done at the Politecnico Di Milano Wind Tunnel, which is legitimate savings in power and gains in speed. I’ve known Steve for a few years now, and I trust what he says, and based on what I’ve learned about making kit aero, I have every reason to believe that he’s right.

Spin class may not be the manliest of test tracks, but it is one of the hottest, and the light weight and breathability of both the jersey and bibs  made them the best suited kit I own for the heat.

But onto aspects that I can speak on with confidence… the Aero Race 5.1 jersey has been in my test rotation for a few weeks now, and I was quickly impressed by its fit, light weight (124grams for my medium), and also the thought and design that Castelli put into it. In fact, time after time, and in spite of their HUGE line of products, I continue to be impressed by how much Castelli really does think about what’s going to make each piece not just stand out, but serve a purpose.


The reason for the Aero Race 5.1’s being was largely driven by their pro team riders who asked for a race-day jersey that could help reduce the watts needed to get through the wind. It’s a very revised version of last year’s Aero Race 5.0 jersey, and this one uses mainly two polyester-based fabrics to get the job done (a third fabric is used for the lazer cut sleeve cuffs.)


Two fabrics are used to make the jersey cheat the wind, and also breathe very well. The front & side panels, and 2/3rds of the sleeves are made from Castelli’s “Velocity Dry” fabric, a dimpled mesh that does two things: disturb the wind enough so that it slips around the body better than a purely smooth surface would allow, thus letting it break free of the body which means you pass through the wind with less resistance. The weave is also three dimensional (it looks like tiny honeycombs), which allows for better air circulation to aid heat and moisture transfer, so you stay cooler and feel dryer.

Up close it’s easy to see how the mesh fabric allows for tons of air to flow through.

The back, pockets, and waist use a fine mesh weave fabric that aids fit by stretching around the body, but holds its shape vertically, so loaded pockets won’t cause unsightly sag. The added structure also helps keep the jersey in place in the riding position.

castelli16-aerorace51-jersey-insideThere’s one other thing that I like – the multiple panel-design has been created to fit a cyclists’s body in the riding position, thereby eliminating bulges and flaps that catch the wind and slow you down. The smoother the fabric lies on your body, the more aero you are. The seams are all sewn on the inside, which keeps the outside of the garment smoother (ie: more aero). The sleeves are long and form fitting, with low-profile lazer cut cuffs that work with the fabrics to eliminate sleeve creep.


The collar is a low profile shape that lies flat against the skin when fully zipped, and the waist gripper is a simple elastic that slides easily over the bibshorts. There’s no silicon gripper used, which I liked here, because it often does the opposite of what I think a well designed jersey should do at the waist – and that’s slide over the body versus sticking and riding up.


This one has become a go to for my riding on really hot days. So while I like that the jersey fits really well and has certain aero properties, the light fabrics breathe very well, and allow more body-cooling air to pass through, so I just feel more comfortable when it gets really hot.

My ultimate test for beating the heat came at my local spin class (note: insert plug for Method Indoor Cycling here) – which I must fully disclose I took to with some reluctance – being a long-time ‘road’ man. But the intense hour-long workouts with a bunch of other people have been a much needed reprieve from the boredom of solo basement trainer sessions, and also a great way to maintain the fitness through my cold wet winters. There’s no hotter space than a spin class, and having worn many a kit for both testing, and style purposes, I’ve worn nothing more comfortable in than this Aero Race 5.1 jersey.

You’ve likely seen this jersey on the backs of the Team Cannondale pro riders, but it’s also offered by Castelli in three inline colorways, and even better as part of their custom program.

• See more info at the Castelli website here.
• Check Castelli Aero Race 5.1 Jersey PRICES here

Trying to get the goods on bibshorts most often comes down to how comfortable are they – and it’s easy for everyone to claim their bibs are the most comfortable – but ultimately the only opinion that matters is yours. Even as a guy who’s tried literally dozens of different brands and models of bibs over the years, I’m only able to report my own experience, and as none of us can ever assume to know or understand what another person’s experience is really like, well… you’ll just have to trust whatever I say.


But… With a little help form some hopefully helpful photos to illustrate, and the fact that yes, I have tried literally dozens of different brands and models of bibs over the years, well, my range of experience gives me some pretty good cred when it comes to kit.

The Inferno bibs by Castelli are a great bib for riding in the heat. Light weight, comfort, and thoughtful design all brought together on a sewing machine operated by a real person make ’em worth a look if hot days are part of your local weather patterns.


They’re made from six different fabrics – which may seem like overkill in this day of multi-stretch lycra – but the whole point of these bibs is to keep you as cool as possible, and Castelli says the best way to do that is apply the best fabrics for the job in specific areas of the bib – and because each part of the bib plays a different role, it makes some sense to assign the best fabric for each job.


The leg bands are a very light and stretchy mesh that is super breathable – they’re about three inches tall, and the inside is brushed with a tiny amount of silicon on the threads so they stay in place on your legs. The large mesh weave of the fabric allows plenty of air through though, os you’d never know there’s silicon present. The material is also very thin – so much so that of you have espcially huge quads, you might notice a small amount of transparency at the leg bands.

The side panels are a light perforated poly, who’s main function is to let hot air out and cool drying air in.  But even better is that the white fabric is sublimated with a special black that actually reflects ultraviolet light rays to helps keep you cooler. There are two heavier-gauge lycra panels inside the thighs that provide structure to balance the lighter side panels, and also some durability where you’re likely to rub against the saddle.


The waist and back panels are a more traditional looking lycra to offer a decent balance of light weight, breathability, and structure. You could make an even even lighter weight set of bibs, but it would fall apart in one ride, and would do nothing to hold your boys in place. No one wants to see either of those things. At the other end of the scale, you could use lycras that hold secure, compress and protect you for a Game of Thrones-style battle, but breathability and comfort go out the window.

The upper back and straps are a perforated mesh that does a good job of letting air flow through, and the there’s a pocket for your race radio as well.

The chamois is sewn to a more durable mesh weave to handle the abrasions from constant pedalling and contact with the saddle.


The chamois is Castelli’s Progetto X2 Air – a long time standard that has seen 17 updates since it was introduced in 2010.  It features multi-density foam (Castelli actually machines foam out of a single foam layer to create the densities (6mm, 9mm, 12mm, and 15mm thicknesses at different parts. which makes more sense than other brands who use heat to compress foam into different densities, but lose the ability to manager moisture and transfer air in place you most want it. My favorite part of this chamois is the smooth, dimpled and seamless layer that sits against your skin – this just makes so much sense in helping the pad find the best place to function between the rider and the saddle, and offer less friction than chamois that run this in reverse or have seams.

Along with the Aero Race 5.1 jersey, I’ve been getting a lot of use from these at my local spin class. Summer’s taking its time arriving, so the hottest place I’m riding is in that gym, and these bibs have proven the coolest and most comfortable pair of bibs I have (in a drawer that is packed with about 30 different kinds of bibs). The mediums fit me well (135lbs and a 30 inch waist), although the leg length is shorter than a lot of other brands offer in a size medium. I’ll keep my eye on the lighter fabrics for durability, and update this review in a few months.

• See more of the Inferno Bibshort here.
• Check Castelli Inferno Bib Shorts PRICES Here


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