Like this site? Help us to make it better.

Castelli Diagonal Women’s Jersey FZ



Close fitting fleecy jersey with outstanding breathability – it's expensive but worth it
Minimal windproofing

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.

What the scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

Castelli's Diagonal Women's Jersey FZ is brilliant for dry, cool-to-cold rides. It does a great job of keeping you warm without excess bulk, and works well with layers to increase its weather-window of performance. Riders committed to performance-focused training will appreciate the levels of breathability this thing offers.

With some practical layering, a thermal jersey like this can be used for virtually every single training ride from autumn through to spring. The FZ is a snug fit, if not quite the race-fit of something like Sportful's Thermal Jersey, and the fabric is really not bulky either.

> Find your nearest dealer here

Consequently, while it performs perfectly well on its own, it can easily take a base layer (or two) beneath or a jacket, gilet or a waterproof on top.

2021 Castelli Diagonal Women's Jersey FZ - hem.jpg

I followed Castelli's sizing chart to test a medium (that's not me modelling it). It's a good fit all over, with a decent sleeve and body length and no tightness around the chest or shoulders. If you're between sizes, I'd say sizing up or down is probably pure preference - whether your want a bit of breathing room, or a very snug fit.

2021 Castelli Diagonal Women's Jersey FZ - collar.jpg

The collar is a good height and sits close to the neck; I can't get a neck warmer on and zip it up without feeling choked. It's not fleece lined here, but the fabric is soft enough (it's the same as the rest of the jersey), if a little less cosy. There's no zip guard either, though the doubled-over material running the length of the zip ensures your neck is not irritated.

2021 Castelli Diagonal Women's Jersey FZ - back.jpg

The cut at the rear is generous, with an added strip of fabric to protect the lower back.

In a riding position, this jersey feels really comfy – there's no pulling or tightness anywhere. It moves well with the body, in and out of the saddle. The silicone strip at the rear hem helps prevent the jersey shifting under the weight of loaded pockets.


On its own, the FZ performs well in temperatures between 12 and 15 degrees. The polyester has a brushed, fleecy inner layer, so it's soft enough against bare skin too. Castelli suggests it can be used up to 18 degrees; obviously, I haven't managed to test this in the last four weeks, though I really wouldn't want to be exerting myself in it above 15 degrees. I started adding layers below 12 degrees.

2021 Castelli Diagonal Women's Jersey FZ - cuff.jpg

With two decent layers, this is actually a decent bit of kit in temperatures as low as three degrees, as it offers exceptional breathability. Head out for some intense riding in colder temperatures and it really does shine. I found absolutely no moisture build up inside the jersey in such scenarios. Naturally, this is also a little dependent on the choice of base layer.

2021 Castelli Diagonal Women's Jersey FZ - cuff.jpg

The FZ doesn't handle rain, but stick on a good waterproof and it continues to perform in terms of breathability. On the occasions I did get caught out (without a waterproof), there wasn't an immediate chill. You certainly wouldn't want to be caught in a prolonged cold shower though; there's very little in the way of windproofing.


I'd say Castelli has got the storage volume and positioning right on this jersey; the three rear pockets are generous and easily accessible. It's worth noting there's no zipped pocket, though.

2021 Castelli Diagonal Women's Jersey FZ - pockets.jpg

There's only a small amount of reflective piping at the rear, too - not really enough to have an impact. The colour I tested scores highly on the visibility stakes however, although in foul weather I found myself having to use stain remover to get it sparkling again.

> 17 of the best winter cycling jerseys to keep you warm when the temperature drops

Still, I'd rather this than ride in dark kit that can render you invisible on a grim day. If you do want to be a little more subtle than this (or the light blue Celeste), Military Green or Light Black may appeal.


Of the three thermal jerseys I've tested so far this autumn/winter, Castelli's offers – by a good margin – the best fit and performance. No surprises it's the most expensive, though. It's a tenner more than Sportful's Bodyfit Pro Women's Thermal Jersey and a whopping £50 more than Altura's Women's Nightvision. I keep harping back to Liv's Race Day Thermal Jersey which impressed me with its performance, even if the cut was a little niche; the latest version is now £74.99.

The Castelli may seem rather a hefty investment, then, but you can still splash out more on the likes of Rapha's Women's Classic or Assos' UMA GT at £125 each.


I've been impressed with the breathability and versatility of the Diagonal Thermal Jersey FZ, and its great fit is the icing on the cake. It's a significant investment but, with supporting kit, it will serve you extremely well for at least three of our four seasons.


Close fitting fleecy jersey with outstanding breathability – it's expensive but worth it test report

Make and model: Castelli Diagonal Women's Jersey FZ

Size tested: Medium

Tell us what the product is for

Castelli says: "Our pro-level printed thermal jersey combines warmth with excellent moisture management. The graphic is designed to look good on its own or under a Perfetto or Aria vest."

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

-Maximum warmth from printable version of our Warmer polyester fabric with brushed fleece inner layer

-YKK® Vislon® zipper with protective tab at top

-3 external rear pockets

-Reflective piping

- 12°-18 °C / 54°-64°F

Weight:306 g

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for fit:
Rate the product for sizing:
Rate the product for weight:
Rate the product for comfort:
Rate the product for value:

How easy is the product to care for? How did it respond to being washed?

Simple – in with the rest of the cycle gear.

Tell us how the product performed overall when used for its designed purpose

Really well with outstanding breathability.

Tell us what you particularly liked about the product

The breathability.

Tell us what you particularly disliked about the product


How does the price compare to that of similar products in the market, including ones recently tested on

This is at the upper end of the price range. Liv's Flava and Race Day Jerseys are both cheaper, as is Altura's Nightvision. Only the like of Rapha and Assos pitch their thermal jerseys at a higher price.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

Brilliantly breathable, well proportioned and versatile, the only thing that could be better is the price – it's a steep investment, but one that should pay off. It's very good.

Overall rating: 8/10

About the tester

Age: 39  Height: 173cm  Weight: 64kg

I usually ride: Road  My best bike is: Carbon road.

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: commuting, touring, club rides, general fitness riding, Getting to grips with off roading too!

Emma’s first encounters with a road bike were in between swimming and running. Soon after competing for GB in the World Age Group Triathlon Championships in Edmonton in 2001 she saw the light and decided to focus on cycling. 

After a couple of half decent UK road seasons racing for Leisure Lakes, she went out to Belgium to sample the racing there and spent two years with Lotto-Belisol Ladies team, racing alongside the likes of Sara Carrigan, Grace Verbeke, Rochelle Gilmore and Lizzie Deignan. Emma moved from Lotto-Belisol to Dutch team Redsun, then a new Belgian team of primarily developing riders, where there was less pressure, an opportunity to share her experience and help build a whole new team; a nice way to spend her final years of professional racing. 

Since retiring Emma has returned to teaching. When not coercing kids to do maths, she is invariably out on two wheels. In addition to the daily commute, Emma still enjoys getting out on her road bike and having her legs ripped off on the local club rides and chain gangs. She has also developed an addiction to touring, with destinations including Iceland, Georgia and Albania, to mention just a few. There have also been rare sightings of Emma off-road on a mountain bike…

Add new comment


RoubaixCube | 3 years ago

Would have been more eye catching if the zip was also slightly diagonal like on some Mavic jackets

Yorky-M | 3 years ago
1 like

how did the jumper get its name?

CyclingSilvers replied to Yorky-M | 3 years ago

From the diagonal strips, I assume.

Latest Comments