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Castelli Flanders Warm LS Thermal Base Layer



Very good baselayer for days where you're working hard, but also overpriced

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Castelli's Flanders Warm LS Thermal Base Layer (quite a mouthful, but there are a fair few Flanders in the range) is designed for keeping you warm during cooler weather, and focuses on keeping you sweat free. It works fantastically well at wicking and is very comfortable, but it's also pretty pricey.

The polyester material on the main body of the baselayer certainly felt great when pulling it on, as did the more mesh-like material under the armpits and the insides of the arms. Similarly, the flatlock stitching adds to the comfortable feeling of the garment.

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The fabric of the arms is slightly elasticated, which manages to avoid the baggy feeling you can get with this type of under layer. Castelli has done well to make a fabric that feels very like merino while maintaining the close fit that it's famous/notorious for. Saying that, sizing comes up well – you can go for your usual, not a size or two larger as with some Italian designs. 

Castelli Flanders warm LS Thermal Base Layer - rear

I wore the baselayer predominantly with another Castelli product I had on test, its rather good SanRemo Thermosuit (review to come). The two make a great pair, but I found it also works really well with pretty much any long-sleeved jersey or jacket.

The Flanders really comes into its own on rides where you're working hard – and sweating hard as a result. Its wicking properties are really good, and considerably better than some other brands I've tried.

Castelli Flanders warm LS Thermal Base Layer - armpit

For me, and many others I expect, price is the big downside. Sixty quid is just too much for what is a fairly simple garment. I've had some really good jerseys on test that are considerably more versatile than a baselayer, while also being considerably cheaper. As such, I can hardly rate the Flanders LS as good value.

> Which baselayer should you buy? Read our guide here

It is a very good garment – it works fantastically well on rides where you sweat a lot in the cold, and the comfort is great, but that still doesn't really justify such a high price tag.


Very good baselayer for days where you're working hard, but also overpriced test report

Make and model: Castelli Flanders Warm LS Thermal Base Layer

Size tested: Large, Grey

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

From Castelli: "We pulled out all the stops to make what we consider the ideal base layer for mild- to cool-weather cycling. The focus is on keeping you dry, so we've worked with multidenier polyester that offers minimal moisture absorption combined with mechanical wicking to move moisture away from your skin. The main body uses a 3D rib-knit structure for exceptional stretch, but with channels that hold the fabric off your skin. The armpits are mesh, while the sleeves have a four-way stretch construction for comfort. All seams and the hem are flat seamed for comfort."

Tell us some more about the technical aspects of the product?

Multidenier 100% polyester 3D-structure rib-knit main body for mechanical wicking and exceptional fit

Perforated 100% polyester mesh under arms for additional cooling

Multidenier 100% polyester 4-way-stretch sleeves for great wicking and fit

4-needle flat-lock stitching lies flat for total comfort

Mock turtleneck

Flat-finish bottom

Longer back stays tucked in

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for comfort, if applicable:
Rate the product for value:

Tell us what you particularly liked about the product

Comfort, and performance on sweaty rides.

Tell us what you particularly disliked about the product


Did you enjoy using the product? Yes

Would you consider buying the product? Probably not, it's a bit pricey.

Would you recommend the product to a friend? If they had the cash.

Overall rating: 7/10

About the tester

Age: 23  Height: 182cm  Weight: 75kg

I usually ride: Kinesis Pro6  My best bike is: The first steel bike I made

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, cyclo-cross, commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking

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carytb | 8 years ago

Premium cycling brand product overpriced. Well I never!

mike the bike | 8 years ago

I'll tell you the only difference between a vest and a base layer.  About thirty quid.

KoenM | 8 years ago

I've gotten one for 50% off, it was only €35, so with that in mind it was an absolute steal and has done wonders in the cold weather heren in Belgium.

mike the bike | 8 years ago

Please stop it with the 'base layer' nonsense.  It's a vest.

Leviathan replied to mike the bike | 8 years ago
mike the bike wrote:

Please stop it with the 'base layer' nonsense.  It's a vest.

Since when do vests have sleeves?

stenmeister replied to Leviathan | 8 years ago
Leviathan wrote:
mike the bike wrote:

Please stop it with the 'base layer' nonsense.  It's a vest.

Since when do vests have sleeves?


When they are 'long sleeved vests'?

Enough with the nomenclature, the point is that you wear this thing under your cycling shirt jersey.

£60 may seem expensive but so too is the Rapha merino vest base layer. I have the Flanders short sleeved vest  baselayer but I bought it in a sale and if I wanted one of these I would wait for the sale too.

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