Castelli Transition review: Between a summer jersey and a winter jacket

In midsummer, it is simple: bib shorts, short-sleeve jersey, done. And when it gets properly cold in winter, there is equally little debate about reaching for the thick jacket. Things get interesting in between, when the thermometer reads ten or twelve degrees in the morning and around 17 two hours later. Sweat pours on the climbs, the slipstream bites on the descents, and by then at the latest you are asking which combination is neither too much nor too little.

Castelli created its new Transition Range precisely for this period. The idea initially sounds simple: it is too cool for pure summer kit, yet still too mild for full-on winter gear. Rather than relying on a single garment intended to cover an enormous temperature range, Castelli offers various pieces that can be combined. The further the temperature drops, the more you can add.

Bib tights normally mean thermal lining, additional insulation and the inevitable feeling that you have finally said goodbye to summer. With the Espresso TRNSTN Bibtight, Castelli takes a different approach. The tights use a pleasantly thin material, similar to that found in Castelli bib shorts. That is precisely their appeal for me. They feel more like extended summer bib shorts than classic winter tights.

At an autumnal 12 degrees in the morning, I felt exceptionally comfortable in them right away. At the same time, the comparatively thin, unlined material prevents heat from building up unpleasantly, even on demanding climbs. Unlike classic winter tights, they remain pleasantly light and provide little insulation. For me, their ideal range is therefore roughly between 10 and 15 degrees – precisely where bib shorts are starting to feel chilly but lined winter tights would still be far too much.

Another highlight is the premium Progetto X2 Air Seamless seat pad. This multilayered, relatively substantial pad is one of Castelli’s top solutions and delivers the customary outstanding comfort. You quickly come to appreciate the extra substance, particularly on longer rides.

I also really like the close, aerodynamically optimised fit. The tights sit smoothly, produce virtually no creases and visually suit their sporting ambitions perfectly. Choosing the size does require a little care, however. With my 92-centimetre inseam and relatively slim thighs, size M is only just right. If you have a comparable leg length but are somewhat more muscular or solidly built, you will probably be better served by going up one size. A side note: my review sample bears the Made in Italy label.

A vest is rarely among the most spectacular items in your wardrobe, yet it is one of those garments you need surprisingly often. The Espresso 2 Vest is exactly that sort of piece. In size M, it fits easily over the Espresso 2 LS Jersey and sits very close to the body overall. The lightweight back material lets plenty of air through, so even short bursts of speed or a climb do not immediately leave you sweating.

The front, by contrast, provides precisely the extra wind protection that a thin long-sleeve jersey lacks on a cool autumn morning. I also find the taller collar very pleasant. It closes neatly around the neck and keeps a good portion of the slipstream out.

The Espresso 2 Vest is a genuine take-anywhere piece. It packs down small and fits quite easily into a rear pocket. When it gets warmer, it disappears; when a longer descent arrives, it is just as quick to put back on. If in doubt about sizing, I would opt for the snugger version, as the lightweight material works best when it lies smoothly against the body. If you choose the vest too generously, the thin fabric tends to flap a little at higher speeds.

For me, that makes it one of those pieces that will definitely accompany me more often during the cooler months, even if only as a backup in a rear pocket.

What is interesting is that the Sweetspot does not feel like a thin wind shell at all. The material has a substantial, premium-quality feel and immediately conveys a certain degree of protection. Even so, the jacket fits pleasantly close to the body. Its high stretch content makes this sporty fit work very well. The Sweetspot fits particularly closely around the arms without restricting freedom of movement.

For me, the cuffs are a genuine highlight. You almost have to work your hands through them when putting the jacket on, but once they are through, the cuffs sit exceptionally neatly around your wrists. There is definitely no unnecessary gap while riding through which cold air could enter the sleeves. I also particularly like the rear hem. It feels premium, sits securely against the body and stays where it belongs in the riding position. Incidentally, this detail is similarly impressive on the Thermal 2 Jersey.

Compared with those on the jerseys, however, the Sweetspot’s rear pockets are somewhat tighter and less stretchy. This keeps everything very tidy, but you need to be a little more deliberate when loading them. The additional zipped pocket for valuables is useful here too. Incidentally, my review sample comes with the Made in Romania label, and the workmanship is up to Castelli’s customary high standard.

In any case, the Sweetspot Jacket is something I decide to wear before setting off. It has a certain amount of bulk and is not the piece I would scrunch down as small as possible and stuff into a rear pocket just in case. In return, it provides considerably more protection and works as a fully fledged outer layer. I really liked the jacket on a cool morning, particularly in combination with the thin Espresso 2 LS. The airy jersey underneath prevents the combination from providing unnecessary insulation, while the Sweetspot does most of the work on the outside.

At Castelli’s stated 7 degrees, however, it would only be enough for me with an additional warm layer. A warm baselayer or an additional insulating layer would be essential for me at the lower end of the temperature range. But when the conditions hit its actual sweet spot, the jacket is one of the strongest products in the entire review for me. Perhaps the name is even more apt than I initially thought.

Temperature ratings for cycling clothing are inevitably subjective. Intensity, wind, route, sunshine and your personal sensitivity to temperature can easily shift the comfort range up or down by five degrees. Manufacturers’ recommendations should therefore be seen as guidance rather than rigid limits. Even so, a few fairly clear combinations have emerged from my own rides.

The Espresso 2 LS Jersey is the most lightweight option and works brilliantly on its own for me in mild conditions. At around 15 degrees, I particularly like pairing it with the Espresso 2 Vest.

With a thin technical base layer, I see the Espresso Thermal 2 Jersey working on its own between roughly 15 and 20 degrees. At around 10 to 15 degrees, adding the Espresso Vest works brilliantly.

The Sweetspot Jacket, in turn, serves a different purpose. It is my choice when I know from the outset that I want more protection and temperatures will remain correspondingly low throughout the ride. Paired with the lightweight Espresso 2 LS, it creates a combination that provides warmth and wind protection without adding unnecessary bulk.

For the lower body, things are pleasantly straightforward: between roughly 10 and 15 degrees, the Espresso TRNSTN Bibtight has felt almost ideal to me so far.