By remixing existing Castelli technologies, the Insider jersey manages to keep pricing lower and does a good job addressing the needs of indoor cycling but the design team should revisit the waist
Pros
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Plastic zipper will not corrode
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Lower price makes it easier to replace often
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3D mesh does a good job of balancing breathability with coverage
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Double rear pockets address the needs of indoor cycling
Cons
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Waist either rides up or folds over
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Zipper bulges at the bottom
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Indoor cycling is unique in the challenges presented on the bike and it’s unique in the equipment needs. Like any cycling, you could grab whatever jersey you've already got and manage - you could even go sans jersey but there are companies that understand the unique needs and have risen to the challenge with specialty products. We've put together a list of the best indoor cycling clothing as a way to help offer some guidance.
One of the brands that's well represented on that list is Castelli. While some brands have chosen to repurpose and rebrand outdoor gear, Castelli has gone beyond. The Castelli Insider jersey does leverage existing Castelli technologies but it's unique compared to the outdoor gear. Did Castelli hit the mark with its indoor-specific design?
We spent time racing and riding through virtual landscapes putting it to the test and now we are ready to share our thoughts. If you like the idea of having the right tool for the job of indoor cycling, then keep reading to see what we think of the Castelli Insider jersey.
The visual language Castelli used for the 2020 warm weather model year is a good look (Image credit: Josh Ross)
Design and aesthetics
This isn't the first version of the Castelli Insider jersey but, this time round, it picks up a new look. If you prefer to keep things simple in black, that's an option. There is also something with a bit more pizazz.
The Fiery Red/Saville Blue colour picks up the design concept from last season's Castelli Aero Race 6.0 Jersey. That means a conceptual design that evokes speed of movement pulling at the colour. Imagine the dark blue is the base with a red over the top. As the rider moves forward the speed literally pulls the red off the jersey and reveals the blue underneath.
Given that indoor cycling means you aren't moving, it's more of a stretch in this setting. Maybe consider the fan blowing the colour off instead of the wind. Either way, it probably doesn't matter much but it does add a cool visual treatment. The effect does break a bit on the side panels though.
It's kind of a shame the side panel doesn't carry the same design (Image credit: Josh Ross)
The pattern Castelli uses for the Insider jersey is simple. Modern outdoor designs often include aerodynamic considerations. That means moving the shoulder seams somewhere that's not the leading edge as it hits the wind. Castelli ends the front panels short and does the same with the rear panels. With no need for aerodynamics when riding inside, the Insider simplifies and ends the front panel as it hits the rear at the top of the shoulder.
The simplification means a single rear panel, one on each side of the front, a piece for each sleeve and another piece down each side of the torso. It's on those side panels that the visual treatment fails as Castelli hasn't matched the effect and instead, there's a solid blue. What has remained the same throughout however, is the fabric.
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The pattern isn't complex and it uses the same fabric throughout(Image credit: Josh Ross)
The edging on the arms is a simple fold over that's quick to situate and comfortable(Image credit: Josh Ross)
The neckline is equally simple and comfortable(Image credit: Josh Ross)
Every part of the Castelli Insider Jersey uses the same 3D-mesh fabric. Look from the back and you can see a series of horizontal waves that are double thickness. As these waves move up and down, coming together then away from each, they create an opposite pattern of negative space. The negative space is half the thickness. It's very similar to the fabric you can find in Castelli hot-weather and climber jerseys. Seeing it in pictures it’s surprising how see through it is. When it’s being worn it feels more modest than the Assos inside cycling approach but the lights and camera tell a different story.
The advantage of this simplification is a lower price point. It's not drastic, and there are certainly less expensive jerseys on the market but it's still appreciated. Inside gear takes a beating and sees frequent use. Anything that helps with more frequent replacement needs is a design win.
The 3D texture helps air move and moisture wick (Image credit: Josh Ross)
Performance
Not only does simplification of design make for a lower price point but it also makes for a fit that's not fussy. Castelli is never going to change its reputation for race fit but the Insider jersey is easy to slip into and comfortable once there. When you are rushing to make the starting line for your virtual race you won't waste time getting things to sit just perfect.
The sleeves, in particular, are just the right length for getting dressed in a hurry. There's no fussy raw cut and instead Castelli uses a very traditional folded end. It slides into place without any hassle and sits there without requiring a second thought. The neckline uses a separate piece of fabric but is otherwise the same comfortable, un-fussy, feeling.
Castelli zippers tend to be some of the best. Large plastic teeth make it quick to zip, or unzip, and immune to corrosion (Image credit: Josh Ross)
What is less successful is the waist of the Castelli Insider jersey. The design shows up on other mid-shelf Castelli summer jerseys but it's a bit different in this use. There's no silicone grip material but rather the grippier fibres in the fabric are woven so they sit on the surface. While jerseys such as the Hors Categorie or Vantaggio use the same design at the front they use actual silicone in the rear. The Insider has no silicone grip and it rides up.
The width of this band doesn't help the case. After pulling the jersey down over and over you will likely pull it down lower than it's meant to sit. At that point it will stay down for a while longer but the motion of pedalling will cause it to fold over on itself.
This waist design isn't great: it rides up, it folds over and it is often a point of annoyance (Image credit: Josh Ross)
It's likely that you can trace these design choices to the rear pockets on the Insider jersey. Castelli knows how to do pockets right. It's always one of the strongest aspects of its clothing and that's the case here as well. Indoor cycling gear still benefits from pockets but they aren't expected to be stuffed with extra clothing, pumps, or tons of food. Recognising the different needs, Castelli chose a two-pocket format without the extensive drop that I love in the outdoor jerseys. It's a successful redesign of the pockets but the way they interact with the waist is a miss.
The pockets may contribute to the issues at the waist but the two-pocket design makes sense for inside riding (Image credit: Josh Ross)
Verdict
The Castelli Insider jersey is not a disaster. Overall, it's a fantastic piece with a lot of great choices. The fabric handles a cold space when you get on a bike but also keeps you cool in the face of low air movement as the riding gets intense. The fit and pattern is simple and comfortable. The pockets are perfect for indoor riding. Even the plastic zipper, despite its propensity to bulge near the bottom, is excellent.
What is not excellent is the waist. It rides up, it folds over and it is often a point of annoyance. It's an outsized miss in an otherwise excellent design. Given how good everything is, it might be worth stashing some gels in the pockets just to keep the jersey from riding up while you enjoy the rest of the design.
Tech Specs: Castelli Insider Jersey
Price: £85 / $119.99 / €74.95 / AU$135
Materials: Lightweight 100% polyester 3D Mesh
Weight: 75 grams in size small
Size availability: XS-3XL
Colour Options: Light Black, Fiery Red/Savile Blue
Josh hails from the Pacific Northwest of the United States but would prefer riding through the desert than the rain. He will happily talk for hours about the minutiae of cycling tech but also has an understanding that most people just want things to work. He is a road cyclist at heart and doesn't care much if those roads are paved, dirt, or digital. Although he rarely races, if you ask him to ride from sunrise to sunset the answer will be yes.
Height: 5'9"
Weight: 140 lb.
Rides: Salsa Warbird, Cannondale CAAD9, Enve Melee, Look 795 Blade RS, Priority Continuum Onyx
