There's no protection against wind or rain but you do get an excellent fit with lots of stretch. The Gore C5 Thermo jersey is a good option when you need a bit of light insulation or paired with other layers.
Pros
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Great fit
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Soft, comfortable, interior
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Zippered valuables pocket
Cons
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Pockets are narrow and sit high on the back
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Zipper has small teeth
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There are a huge range of experiences when it comes to shoulder season riding. Is it sunny but crisp? Is it windy, or rainy, or maybe dry but overcast? Whatever the situation, there's a range of strategies for dealing with it. The Gore C5 Thermo jersey could be part of some of those strategies.
We listed the Gore C5 Thermo jersey among our list of the best cycling jerseys no matter the weather conditions, but there's more to say about it. We spent time testing it to see what it excels at and what its weaknesses are, so keep reading to see when we think it makes sense to use this piece of gear.
The sleeves are on the long side but comfortable on a bike. (Image credit: Josh Ross)
Design and aesthetic
Arm warmers are often some of the cosiest and most comfortable pieces of cycling gear to wear. A great long-sleeve thermal jersey is a lot like an arm warmer that works for your whole core. When it comes to the Gore C5 Thermo jersey, some of the fabrics are even the same as what you'll find on the brand's arm warmers.
For the Thermo jersey, there are two main fabrics and one extra. The main body of the jersey is a thermal fabric with a makeup comprised of 91 per cent polyester and nine per cent elastane. The outer face is soft but smooth, while the inner face has a brushed finish that feels incredible against the skin. This fabric lacks a membrane of any kind, and it also lacks any DWR (durable water repellent) treatment. Without those two features, there's no protection from either wind or rain, so as soon as water hits the surface it's quick to soak in, and wind will cut through virtually unimpeded.
The secondary fabric in use shows up on the sides of the garment and travels up the underside of the sleeves. Whatever colour you decide to choose from the five options available, this panel is a slight variation. The colour change comes primarily from the fact that it's a slightly different fabric. There's no brushed inside and the elastane content is nearly double at 16 per cent. These areas provide a bit of additional stretch as well as extra breathability, and also happen to be the same material as Gore's non-windblocker arm warmers.
Almost the entirety of the back of the Gore C5 Thermo jersey is the same fabric as the front, but there is a third fabric that shows up near the wide gripper at the bottom of the piece, where the three pockets sit. The outer two pockets are narrower than the centre, and on the right is a fourth zippered valuables pocket. Behind the pockets as well as below them is a highly breathable mesh that keeps sweat from building under full pockets.
The pockets work better than other Gore tops because there's so much stretch. (Image credit: Josh Ross)
Performance
I brought up arm warmers in the first section because that's exactly what this Gore C5 Thermo jersey feels like to me. There's the same level of compression in the arms and the same super soft brushed material that you find on the best arm warmers. Without extra weatherproofing features, that is also how I like to use this piece.
There's a lot of overlap between arm warmers and a long sleeve jersey. The obvious difference being that one is easy to shed while the other is not. When I head out for a cool, dry day with no wind, but I know I won't be shedding layers mid-ride, then I'd rather use this Thermo jersey instead of arm warmers. The protection might be similar but there are fewer layers.
For some people, the lack of DWR or wind protection could be detrimental to the usefulness of the C5 Thermo jersey, but it can also be advantageous. If you need wind protection, it pairs well with the Gore Windstopper base layer, and if you need some weather protection, a lightweight shell or vest is a good addition. The fit is tight enough that it's not a problem to layer when needed.
The last time I took it out was a 105-mile mixed surface ride with substantial climbing. I spent just under eight hours in temperatures ranging from 50-55 F/10-13 C and occasional rain. I paired it with light bib tights, the Castelli Idro Pro 2 jacket, and the Sportful Bodyfit Pro long sleeve base layer, and it was a perfect choice. I've also had success wearing it on warmer days when it's overcast and paired with thermal bib shorts.
The one weak point with Gore tops continues to be the pockets. In this case, they still sit a bit higher than is comfortable on the back, and the outside pockets are overly narrow. However with the C5 Thermo jersey, they are better than other designs from Gore because of the fabric; the extra stretch makes them more useful and easier to reach, though they aren't perfect. The valuables pocket is, as always, a nice addition but it's far too small for a phone, so expect it to be cards and keys only.
The collar on the Gore C5 Thermo Jersey is a thing of beauty. Really soft and comfortable. (Image credit: Josh Ross)
Verdict
The Gore C5 Thermo jersey feels a lot like a pair of arm warmers for your whole core, in that the fit is compressive but comfortable and it's very soft on the interior. The lack of DWR coating or a membrane for wind or water means it's best used as light insulation against chilly temperatures. If you need more than that, then stepping up to the best winter cycling jackets or simply adding another layer above or below are good options. The zipper could be better, but there is a zipper garage at the top and it works well enough. The only real miss is pockets that are a little too high and too narrow.
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
