Castelli Alpha Jackets
19 October 2023
By George Wise
Back in 2014, Castelli launched the first Alpha Jacket, which set a new benchmark in Winter jacket performance. The Alpha Jacket was revolutionary because of its dual layer design on the front, meaning the outer fabric was separate to the thermal inner layer. The principle was simple; by undoing the windproof outer layer, you allow air to come into the jacket to help cool the rider. Whilst the inner thermal layer acts like a wind diffuser to prevent cold air directly hitting a potentially damp baselayer and causing the riders temperature to drop too much and causing discomfort. The outer layer is also attached to the inner layer at the sides, so if you do fully unzip the front of the jacket, it doesn’t flap around and is easier to do back up.
For the 2023 season, I decided to step away from my trusty S Works Tarmac SL7 and try out the new ENVE Melee.
So why would you need this? As a scenario, in summer many riders will undo their jerseys to help regulate temperature when on a climb or doing an effort. This isn’t a problem, as the warm summer air is pleasant against a damp baselayer. In winter though, if you were to start overheating on a climb and wanted to undo your jacket to cool down, you would usually be exposing your damp base layer direct to the winter air. If you are a rider who wants to do efforts, has lumpy winter rides or is prone to running hot, then the Alpha jacket could be a game changer.
New for AW23, Castelli has updated the Alpha jacket range with the introduction of the new Alpha Flight ROS and Alpha Doppio Ros Jackets to accompany their already existing Alpha Ultimate Jacket.
The 2 new Alpha Jackets replace the previous Alpha ROS 2 and Alpha Light ROS 2 jackets. By using new materials and designs, Castelli have been able to create 2 jackets which offer better performance, fit and temperature versatility compared to their predecessors.
Alpha Flight
The new Alpha Flight is designed for use between 6 to 16°C: Ideal throughout British Autumn and mild Winter days.
The jacket features the brilliant Polartec ® Alpha ® Direct thermal fabric on the inside, whilst the outer layer is constructed using a combination of Castelli ‘s own Nonaflex Light and Nanoflex Extra dry fabrics. Both of these Nanoflex fabrics are water resistant and offer a level of wind resistance, but more importantly offer a 4 way stretch and are incredibly light and breathable. This creates a high performance winter jacket that is still aero and feels fast.
To aid with further water resistance, the Alpha Flight also features taped seams on the shoulders. This is to help reduce water ingress on the most exposed part of the jacket from driving rain (or if following someone’s wheel when they don’t have mudguards).
The addition of an asymmetric YKK zip means you don’t get the zip digging into you when on the drops, and 3 pockets offer plenty of space for all your accessories. There is also a security pocket for keeping items like a bank card extra safe.
With the more mild winters that we are now seeing in the UK, the previous Alpha Light jacket was a staff favourite at Saddleback and we can’t see it being any different with this new Alpha Flight ROS jacket paired with some Semifredo Bibtights. With the switch of a baselayer, it is incredibly versatile across a large temperature range and offers enough protection against but persistent rain.
The jacket retails for £290 and comes in 4 colours: Light Black, Tarmac, Belgium Blue or the bright Sulphur.
Alpha Doppio ROS
The new Alpha Doppio jacket replaces the much loved Alpha ROS 2 Jacket: But all for the better. Designed to be used in the harshest winter months, it has a temperature rating of between 10 to -5°C.
The Doppio jacket is an amalgamation of the best parts of previous Alpha Jackets to create a ‘greatest hits’ from each generation. Changes to the panelling construction, tweaks to fit and various features mean it’s the best fitting, highest performance version yet.
For the main construction, the jacket features a GORE-TEX Infinium™ Windstopper 150 outer layer which is both water resistant, windproof and incredibly breathable. Whilst not as stretchy as the Nanoflex fabrics on the Alpha Flight Jacket, the GORE-TEX Infinium™ Windstopper 150 does offer superior weather protection. For the inner thermal layer, again the excellent Polartec ® Alpha ® Direct fabric is being used.
To increase protection from rain, the Doppio also features taped seams on the shoulder to prevent water ingress in this exposed part of the jacket, whilst other non-taped seams are stitched in a way to minimise water ingress.
The jacket also features large vents at the back to allow moisture to escape when things warm up, whilst a double cuff system allows seamless integration of your gloves to prevent any cold air going up your sleeve. The double collar is designed to prevent a similar scenario with cold air going down your neck when changing position on the bike. Like the Alpha Flight, this jacket also features an asymmetric zip to add further comfort when on the drops.
Lastly, 3 large pockets and a security pocket bring practicality to this performance winter jacket.
The Alpha Doppio retails for £350 and comes in 4 colours, light black, rover green, popeian red and red orange.