Castelli Sanremo 4.0 Speed Suit

The new Castelli Sanremo 4.0 Speedsuit hasn't seen a massive redesign over the 3.0, more of a fettle to refine the details – but it works. After all, why mess with a classic? Make sure you go up a size though, as it's a much snugger fit than the majority of Castelli's range.

• Pros: Excellent pad, great choice of fabrics
• Cons: Castelli's size guide doesn't work for the Sanremo

When I was time-trialling, Castelli's Body Paint Speedsuit was my clothing of choice. It was expensive, fragile and you couldn't stand up in it because it was designed in such a way that there wasn't a single wrinkle or piece of flapping material when you were stretched out on the aero bars. In fact it was so small and specifically designed that on the hanger it wouldn't look out of place in a toddler's clothing section. It was amazing, though, and the Sanremo takes a lot of its thinking and comfort but in a more real world application.

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You still get the super-close fit, so when you are hammering along on the flat the material is stretched closely to the body, but although the shoulders may feel a little tight you can still walk around off the bike or stand up out of the saddle for a climb without the zip busting open.

It has all the practical benefits of wearing a pair of race shorts and jersey, but with the added aero benefits.

The lower portion of the suit is based on Castelli's Free Aero Race 4 bib shorts which use the Progetto X2 Air Seamless pad. This has a range of differing density foam across its layout but, like a lot of other pads we've seen lately, without any form of channelling between them for reducing pressure.

It's lovely to sit on – a really great balance of comfort and support for long rides, especially those where you are crouched in the saddle in one position, making yourself as aero as possible while smacking out the watts.

The only seam is the one that runs around the outside so there are no rubbing issues no matter how long you are riding for.

Aerodynamics is key here so Castelli has used computational fluid dynamics (CFD), software to mimic airflow, at the design stage to perfect the Sanremo, so you'll find that all of the fabric choices and seam layouts are positioned to achieve the best possible outcomes. We are talking tiny parameters here, mind, especially in the real world.

Castelli has used its Vortex fabric on the legs, which has a dimpled finish for an aero performance, while on the inside of the thighs it's gone for Forza – a material that has a high 38% Lycra content for a really close and supportive fit.

Keeping everything in situ are Giro4 leg grippers. They are quite tall to spread the compressive load, and on the whole are quite comfortable.

Up top, the jersey uses Velocity Rev2 fabric on the front and sleeves for a close and aerodynamic fit, while the rear is made of a lighter mesh style fabric to aid breathability. It's a good combination that allows you to ride hard without getting overwhelmed in sweat, doing a really good job of keeping you dry.

Castelli has changed the pocket layout on the 4.0 to give you better access on the fly. Feedback was that the three narrow pockets were a bit of a faff to reach into at times, so this new edition has just the two but much wider.

They are still deep and taut enough to keep things secure when riding in a crouched, flat back position, and I did find it easy to reach back to grab a snack or my phone without issue.

Sizing

As I've mentioned, the fit of this skinsuit is supposed to be close, but a word of warning: Castelli has a single size guide for all of its products. I'm usually a medium in its clothing if I want a snug fit, but I'm glad I had the large in the Sanremo. It fitted well, though I would say I was right at the upper limit of what is acceptable, so you'll definitely need to size up by at least one.

Value

Now, value. At first glimpse the price looks mental at £240, and while many of you will still shake your heads and mutter under your breath while I have a go at justifying it, bear with me.

The Free Aero Race 4 bib shorts that these are based on are £150 on their own, and while Castelli doesn't base the jersey on anything specific in the range, the Aero Race 6.0 Jersey FZ is pretty similar and that'll cost you £110. So while the Sanremo isn't a bargain, you are getting a bit of a discount.

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A cheaper option, though, is the Endura Pro SL Roadsuit for £179.99. The Castelli has the better fit and what feel to be better materials in terms of comfort, but the Endura does have a very good pad plus you'll have 60 sheets in your back pocket so it's definitely a contender.

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Overall, the Sanremo has lost none of its edge over the competition. It's a very well made piece of kit that performs well, and as long as you bear the sizing in mind there is little to dislike.

Verdict

A well-executed compromise between an aero skinsuit and a jersey/short combination – a quality piece of kit for racers