When every second counts, aerodynamic kit can give you the edge. Castelli’s Sanremo S speed suit is built for racing, with a fit that puts aerodynamics front and centre, yet it also features rear pockets that make it a viable choice for long-distance efforts, gravel events, and even cross-country racing. Comfort hasn’t been sacrificed, and for those who like to keep things understated, there are other colour choices.
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Castelli Sanremo S Speed Suit – Technical Details
Originally developed for time trials to maximise aerodynamic efficiency, skinsuits and speed suits were later adapted for road racing with the addition of rear pockets, adding versatility without sacrificing the aero gains over a traditional jersey and shorts combination.
The Sanremo S Speed Suit represents the latest step in that evolution, blending features from Castelli’s Aero Race 8S jersey with its Free Aero Race S bibshorts. It comes in sizes from XS to 3XL, and Castelli’s detailed sizing guide takes multiple body measurements before recommending a size, complete with a dial showing fit preference from slim to relaxed for both chest and hips. This is especially handy for riders who usually need different sizes in shorts and jerseys.
The fit is in line with other Castelli garments, though the aerodynamic profile means long sleeves and extended leg length. Shorter riders, myself included, may find the cuffs sit close to the knees and elbows. According to Castelli’s fit calculator, I fall into XS, but in other Castelli kit I am comfortable in size S, and I have found the XS to be too tight. I would be curious to try an XS to see if it shortens the sleeves slightly. Otherwise, the cut is the brand’s typical aero-optimised close fit. There are no height options for sizes, which is an option with other companies, including British brand NoPinz, who have sizes 2XS to 2XL, but also Standard and Tall options.
The Sanremo S is available in the White and Deep Mocha colourway tested here, as well as a plain black option.
Castelli Sanremo S Speed Suit – Performance
The fit is close to perfect. Standing up, a few fabric folds appear, but these vanish completely once in a riding position, which is exactly what you want. On a drop-bar gravel or road bike, the suit sits flawlessly, and it remains well-fitted even on a cross-country mountain bike’s more upright position. Compared with Castelli’s Aero Race 8S jersey, the Sanremo S feels more stable and does not roll up at the back, which I found the Aero Race 8S has a habit of doing.
Without lab testing, it is hard to measure aerodynamic gains, but the smooth, fold-free fit will help wherever speed matters. Comfort is excellent, thanks to the lack of bib straps and the even fabric tension. My only minor niggle comes from my build, as I need to position the sleeves so they do not fold and brush the inside of my elbow.
The Progetto X2 Air Seamless seat pad, taken from Castelli’s flagship shorts, is outstanding. Its standard placement makes the Sanremo S more versatile than time-trial-specific suits that shift the pad forward. It works equally well for road, gravel, and XC MTB riding.
The jersey fabric is thin enough that body hair is visible when wearing it without a base layer, and likely more so in the white version. Castelli rates it for 15–35°C, which feels accurate, but a thin sleeveless base layer improves comfort in cooler weather and reduces transparency.
Practicality is strong. The jersey section unzips fully for easy comfort breaks, and the rear pockets match a standard jersey for capacity. The close fit keeps items secure against your back, though awkward shapes can create a bit of pressure.
Castelli Sanremo S Speed Suit– Verdict
A speed suit will not appeal to every rider, but for racing, even off-road, the benefits are real. The faster you go and the longer the distance, the more those gains add up.
At £300, the Sanremo S is undeniably expensive, but compared with Castelli’s own Aero Race 8S jersey (£170) and Aero Race S bibshorts (£200) combination, the pricing looks more reasonable. There are cheaper alternatives, such as No-Pinz’s Pro-1 Evo Gravel at £190, and more gravel-specific options like Sportful’s Fast Not Fun, which adds side-panel pockets. Rule28 also offers gravel and TT-focused suits, ranging from £250 to £600.
What sets the Sanremo S apart is its balance. It combines the aerodynamic efficiency expected of a high-end skinsuit with practical features like full-size rear pockets, making it versatile enough for road, gravel, and XC racing. Comfort is a standout, helped by the lack of bib straps and the excellent Progetto X2 Air Seamless pad, which makes long rides a pleasure rather than a compromise. The only drawback is the extended sleeve and leg length, which may feel excessive for shorter riders.
Overall, the Sanremo S is a premium but highly capable choice for anyone who wants race-level aero gains without sacrificing comfort or practicality.
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Product purpose:
The next evolution of the suit that started a revolution. Before the Sanremo Speed Suit made its debut in 2011 at Paris-Roubaix, the thought of wearing a speed suit for anything but a time trial seemed insane. But after it achieved victory in its first outing, the way cyclists dressed for racing changed forever. In its latest evolution, the Sanremo S Speed Suit is even faster. The top part uses our newest and fastest Aero Race 8S Jersey with CFD seam placement and engineered ribbed fabric on the sleeves for an aerodynamic advantage. The bottom is based on our new aero-optimized Free Aero Race S Bibshort. As always, the suit opens completely in the front for added ventilation and easier nature breaks and has three pockets on the back for storage. We’ve also used our Progetto X2 Air seat pad for comfort during the toughest rides or races.
Build extra:
Insulation
Waterproofness: 1/5
Windproofness: 1/5
Breathability: 4/5
Lightness: 4/5
Weight: 283 g
Temperature: 15°C – 35°C / 59°F – 95°F
Fit: Race
• CFD-based fabric placement and seam construction
• Engineered shoulder fabric used specifically to reduce drag at race speeds, with as much as 6% savings in CdA
• Bonded sleeve endings for comfort
• Lightweight body fabric for optimal cooling, breathability, and comfort
• Aero-optimized Forza2 Stretch fabric for maximum comfort and aerodynamic advantage
• Aero-optimized fabric delivers 3% decrease in CdA
• Silicone leg grippers to keep leg endings in place
• Progetto X2 Air Seamless seat pad for comfort even on your longest rides
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