The RS Superleggera from Castelli is lightweight, but aimed at general riders rather than out-and-out racers. Castelli says it uses fabrics and tech from its pro race jerseys to offer excellent comfort at a very low weight, minus the uncompromising focus on pure speed. And it works rather nicely. If you're off to the mountains and looking to cut grams wherever possible, this comes in at a barely-there 106g (compared with a more typical 150-180g for a summer jersey). Unlike some other lightweight jerseys we've tried, there are really no significant compromises to hit that weight.
Cut from a range of diaphanous fabrics, Castelli says this (along with most of the rest of its output, in reality) will fit best on those with "more athletic body types", but it is notably more forgiving than some of their racewear and all the better for it (assuming time trials aren't why you bought it). I'm generally a large in Castelli sizing, at 6ft 2in, a shade over 80kg and with a 39in chest, and I found the fit to be spot on here. That's not me in the pictures, by the way.
The temperature round these parts hasn't yet reached the giddy summer heights, but I found that paired with various base layers this was pretty spot-on for the mid-teens of spring afternoon riding; it's certainly not something you'd have to save for the hols abroad.
The Futura fabric (the blue bits) is really soft and light and very comfortable against the skin. It is pretty stretchy in the horizontal direction, allowing it to fit a wider range of body shapes. The black side panels are a highly breathable mesh designed to keep you cool when the mercury rises.
One of my favourite things about this jersey is the efforts that Castelli have put into pocket stabilisation. One of my bugbears with the ultralight Adizero jersey was that if you put a phone (a good bit heavier than the jersey) in one of the two side pockets, it pulled the jersey round to that side.
No such issues here thanks to two great pieces of fabric engineering. Firstly, there's a more compressive 90g stretch fabric used around the lower part of the jersey (the black part) which hugs your lumbar region and holds the jersey and the contents of the pockets nicely in place. Secondly, there's an inner layer of "3d mesh" on the back whose job is to provide vertical support and stop sagging. This covers the whole area between the seams that run up to the shoulder blades, and the mesh has plenty of horizontal stretch to avoid pulling tight across the shoulders but almost none of our old friend, vertical compliance. What that means here is that the weight of whatever you've stuffed in the pockets is supported right up your back to your shoulders, and it works a treat.
Castelli says that whereas the pros have team cars and hence don't need to load up their pockets, they recognise that the rest of us generally need to carry more than a couple of gels, and that led to the design of this jersey. The two side pockets are big enough to swallow a large modern smartphone and the centre pocket could take a pair of leg warmers or a lightweight shell or gilet. They've also included a zipped valuables pocket on the right-hand side for keys or coins, emblazoned with the words "You know you're getting an unfair advantage".
Unfair or not, (and you're certainly paying a fairly handsome price for that advantage), this is a really well-designed summer jersey. Yes, it is very light, but for me that's not the main point here, as it's also a super-comfortable and practical top for sunny days out. £115 is a big price for a summer jersey, a little less than what Rapha asks for its Pro Team Lightweight jersey, and may well be more than you're willing to pay, but if you're in the market for a primo "general purpose" warm-weather top (as opposed to out-and-out racewear) then I would certainly recommend this. It's debatable whether saving 50g off the weight of your jersey is really a worthwhile endeavour, but if it can be done without gratuitously compromising the other functions of a jersey, then why not? The RS Superleggera is available in a handful of fairly muted colour combinations.
Ultra-light without the usual compromises on practicality - a lovely summer jersey for the mountains
road.cc test report
Make and model: Castelli RS Superleggera Jersey
Size tested: Large
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?
Castelli says: The inspiration for this jersey came while riding Switzerland's Flüela Pass between Davos and the Engadin Valley. The air is thin as you approach this 2383m pass, and I was pushing hard on a 230km ride. I could hear the winding engine of the supercar coming up the valley, and before it reached me I could actually feel the rumble as it approached redline. That Lamborghini Superleggera was a road-going version of Formula One technology, and this jersey represents the same the concept. Here we are using technologies and know-how developed for the highest levels of pro racing, adapted into an extremely lightweight and aero road-going jersey. We've used bits of our 50g stretch woven fabric, our ultralight and ultra-wicking Futura 50g fabric on the front and sleeves, and a 3D mesh fabric liner on the back to support the pockets, and added a handy zippered key pocket for some creature comforts.
Tell us some more about the technical aspects of the product?
Futura 50g main body fabric is lightweight with excellent moisture management
Compression band in 90g stretch woven fabric keeps pockets in place
Full-length front zipper with neck protection
3D mesh fabric insert in back to support pockets
3 open pockets plus zippered key pocket
Floating rear pocket design
No-sew trim at sleeves and waist
Weight: 81g (claimed - we weighed our large at 106g)
Reminiscent of other Castelli tops, so nicely put together. Seams are a mixture of flatlocked and conventional and the stitching is neat and there are reinforcements at high-stress points. Glued-on tape rather than stitched hems at the sleeve ends and the bottom of the torso make for a neat finish. The more compressive fabric around the bottom of the torso does a great job of keeping the pockets stable.
Unlike other superlight tops (Adidas, I'm looking at you - http://road.cc/content/review/129668-adidas-adizero-jersey) this doesn't feel compromised in other areas to hit the target weight. It's a pleasure to use, in fact.
No issues in testing - it's quite lightweight but there are no obvious weak points that I'd expect to fail too soon.
A nice compromise - fitted but not tight. Much more every-day-wearable than some of Castelli's out and out race kit, and better for it, if you're not racing.
I'm usually a large in Castelli tops and this fitted well in that size.
Our large size might be heavier than their claimed 81g, but it's still pretty light.
It's an expensive top, but there are features that I've seen trickle down from higher up their range.
How easy is the product to care for? How did it respond to being washed?
Tell us how the product performed overall when used for its designed purpose
Comfortable, very light, and with great fit - I enjoyed wearing this.
Tell us what you particularly liked about the product
Really high quality summer wear that isn't just aimed at racing. Superb design of pocket stabilisation (both lateral and vertical) is the best I've seen on a lightweight jersey.
Tell us what you particularly disliked about the product
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 score
Very nicely designed and a pleasure to wear, albeit at a chunky price.
About the tester
I usually ride: On-one Bish Bash Bosh My best bike is: Rose X-Lite CRS
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: road racing, time trialling, cyclo cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mtb,
Jez spends his days making robots that drive cars but is happiest when on two wheels. His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding.