A high-quality bib that looks good, feels good, and sports a couple of little tweaks that make it great for indoor cycling
Pros
+
Mesh leg endings
+
High wear saddle contact area
Cons
-
Radio pocket is unnecessary
-
Main fabric is both heavy and overly transparent
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Indoor cycling is a large part of the fabric that weaves the modern cycling landscape together. In the same way that you wouldn't expect road cycling and gravel cycling to use the same equipment, it's unreasonable to expect that indoor and outdoor cycling use the same gear. Indoor cycling is a unique challenge with unique needs and some of the best companies have risen to that challenge.
If you are looking for clothing specifically designed to cover the challenges of indoor cycling then Castelli has to be on your radar. We included multiple Castelli pieces in our guide to the best indoor cycling clothing because they are one of the few brands that have developed specific gear. The Castelli Insider bib shorts aren't a recycled design with new branding. They are a unique collection of Castelli technology targeting the needs of riding inside and we've put them to the test. After many hours of sweating through virtual landscapes seeing what they are like, we are ready to talk about them. If you feel like you are ready to stop recycling old bibs or using your best cycling shorts for your sweaty indoor rides, and instead step up to purpose-built gear, keep reading to see what we think of the Castelli effort.
Those panels that look blue are officially black but the dye sublimation process means they look bluer when worn. (Image credit: Josh Ross)
Design and aesthetics
The design of the Castelli Insider bib shorts isn't completely unique. It's unusual for a company like Castelli to completely redesign a pattern so that's not an issue, or even unexpected. In this case the design comes from the Inferno bib shorts. The Inferno bibs exist for riding in the hottest weather so it makes sense to start there for an indoor specific bib. The two aren't exactly the same though.
The most notable similarity is the unique Giro Air mesh leg endings. Castelli refers to them as leg endings but they are the only grip material that exists on the Insider bibs. They lack any additional silicone grip but the internal surface has a certain stickiness even without the need for extra material. Castelli handles this by using the higher friction threads in the fabric and setting them at the surface in a specific pattern that allows them to come in contact with the skin. In combination with the reduced lateral stretch and tight fit, there's no need for anything more. The band is also plenty wide enough to keep the thigh from feeling squeezed.
The mesh leg openings are one of the best parts of the design. They are cool, comfortable, and look great. (Image credit: Josh Ross)
Above the mesh band, the front and outer area of the thigh are two panels, both using the same fabric. Although the official colour is black, it bears a striking resemblance to the Saville Blue available on the matching Insider jersey. Part of that colour discrepancy comes from how Castelli applies the colour. While some Castelli pieces use a traditional dye, the Insider bib shorts undergo a dye sublimation printing process. Instead of changing the colour of the fibres, the colour gets printed to the face of white fabric. Flip the bibs inside out and you can see that these panels are white. When pulled tight that white bleeds through the colour and changes what should be a black into a grey/blue colour. The upside of this process is the logo gets printed at the same time and will never crack, or peel, off - a common complaint on some of Castelli's other gear.
On the inner thigh, and under the chamois, you'll find a different fabric. It's a higher nylon content to help it hold up to the wear and tear of saddle contact. It's also truly black, like the mesh grip area, and you can see the colour differences in all the various panels.
For the chamois, Castelli has gone with the Kiss Air 2 pad in the Insider bib shorts. You might think of the Kiss Air 2 pad as lower quality, compared to the Progetto X2 Air, but that's not really the case. It’s different and while the Progetto X2 Air is better in some situations, the Kiss Air 2 is still one of the best chamois options on the market. It just lacks the gel pressure point protection of the Progetto. It's also a little bit thinner and it doesn't float freely in the same way as the other pad. For shorter rides and higher intensities, like typical trainer rides, the Kiss Air 2 makes a lot of sense and might even be the better option.
The Kiss Air 2 chamois pairs well with the needs of indoor cycling. (Image credit: Josh Ross)
Performance
I wear a lot of bib shorts. I constantly talk about tiny performance benefits of one design vs the other and how brands tell a unique story for one product vs another. Just like anyone though, when I pull on a bib short and look great in it, I'm a fan. That's even true for an inside specific short that no one is going to see.
In this case though, my perspective of looking good comes from the same design decisions that drive the performance. In an effort to make the best bibs for hot weather performance the legs on the Castelli Insider bibs are short. That means they fall right in the meat of your thigh. I'm no track sprinter but I like the way my thigh looks under the mesh of the leg endings. It’s a silly thing but I’ll take what I can get.
There are other details, actual performance details, that contribute to my appreciation as well. I often rave about the Castelli chamois decisions and I can do it again when it comes to the Insider bib shorts. I think I would have been equally happy about the Progetto X2 air but in all the time I've spent in these, I've never felt let down by the Kiss Air2. Spending an hour racing, often out of the saddle, is not a torture test for a chamois but the Kiss Air2 does a good job of staying out of my consciousness, which is about as good a compliment as there is for a chamois pad.
The shoulder straps and rear use a mesh that breathes well but doesn't roll up. (Image credit: Josh Ross)
On the other side of the chamois is another detail I appreciate. There's no pair of bibs that takes more of a beating than the ones I wear inside. Despite riding significant miles, I very rarely feel the need to retire outside bib shorts. Indoor gear on the other hand frequently needs replacement and when it comes to bibs, the saddle area is sometimes a culprit. Using a higher wear fabric in the saddle contact area is a choice that makes a lot of sense.
As you move up the bibs to the straps there's another choice I appreciate. The radio pocket might not make much sense but the particular type of mesh Castelli uses for the Insider bibs is a good choice. Like the leg ends, this is another area where heat can sometimes build up. Castelli uses different fabrics in different bib shorts to accomplish the same venting but for the Insider, it's another good balance of light without constantly rolling up.
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The back of the primary fabric on the thighs is white while the front is black. (Image credit: Josh Ross)
There are different colours of black in different areas does to differences in construction.(Image credit: Josh Ross)
Verdict
The Castelli Insider bib shorts might not be the best indoor cycling option for everyone. Although the design comes from the Inferno hot weather bib shorts the fabric used is a little bit thicker than those bibs. The leg endings and the straps use a lightweight mesh that vents well but the main fabrics are a little bit heavier.
It works well for me because my "pain cave" is cold in the winter. Something like the Assos Equipe RSR Bib Shorts Superléger S9 is great when it's warm but in December and January, I need something with more substance. If that's what you need the Castelli Insider does a better job of handling a cold start but continuing to perform when the racing gets hot. If you ride inside in a temperature-controlled room you might want a lighter option. As long as your temperature preferences match up the Castelli Insider bib shorts are an excellent indoor riding option at a great price.
Tech Specs: Castelli Insider bib shorts
Price: £130.00 / $139.99 / €119.95 / AU$199
Weight: 150 grams in size small
Size availability: XS-3XL
Colour Options: Black
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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
