Isadore Signature Merino Air Jersey

The Isadore Signature Merino Air Jersey is a highly breathable, stylish summer top with a great fit. It does a good job of protecting you from the sun too. It's a pricey option, but if you have the money it is very good.

For more (mostly cheaper) options, check out our guide to the best summer cycling jerseys.

> Buy now: Isadore Signature Merino Air Jersey for £145 from Isadore

The Signature Merino Air Jersey is designed to keep you cool on hot summer days – Isadore suggests a temperature range of 20°C to around 32°C. I wore it throughout that range and even hotter and it performed really well.

The main fabric is 61% merino combined with recycled polyester and polyamide, while the Polartec Delta – used for the rear panel, sleeves and pockets – is designed to wick sweat away from the body and keep you cool and dry.

It's certainly very breathable. On a recent trip to Italy I did a huge eight-hour ride in the mountains in 30°C heat and the jersey was great: the upper back was a bit damp at the top of the climbs but dried out quickly once I picked up some speed. You really feel the wind cooling you down once you pick up some speed.

The material also seems better at dealing with the sun than some summer jerseys. After a few all-day rides in the heat I didn't end up with bib-strap tan lines on my back like I have done in the past. Still, I'd prefer to be safe while wearing a summer jersey and cover myself in suntan lotion before a long ride.

If you want to let more air in, the front zipper is good quality and easy to use while riding. Where you park the zip pull is more car port than garage, but with the jersey's slightly lower neckline it wasn't an issue and doesn't irritate.

Despite being light and breathable, the materials and dark colours on the body mean it isn't see-through, which I always appreciate. It's available in Bottle Green as well as this Anthracite, which looks good too.

Fit & sizing

Though the jersey is described as a 'medium compression relaxed fit', I found it a very close-fitting top, and really quite tight around the upper chest. I liked it, but it wasn't quite what I was expecting.

As is the trend these days, the sleeves are on the longer side, but the jersey itself is on the shorter side. I'm 178cm and there was a risk of stomach exposure when off the bike but only when paired with my low-fronted shorts.

Lightweight gripper all around the bottom worked well at keeping it in place; it didn't need adjusting during a ride.

The jersey comes in seven sizes, XS-XXXL, and I tested the medium (my usual size). The size guide suggested I was towards the lower end of medium (I am 178cm and 73kg), and it was fine, but it was smaller than I expected. If you're towards the upper end of a suggested size, you might want to go for the next one up, but check the guide.

Pockets

At the back there are the usual three pockets. These are medium sized and comfortably held a gilet, plenty of nutrition, and my phone without feeling overloaded.

There is a zipped valuables pocket, too, which is a perfect size for your card and keys. This was good to see as not all summer jerseys have such a pocket.

Value

At £145 it is quite expensive for a summer jersey that you'll likely only use for part of the year. The Castelli Endurance Pro 2 received a very good review and is £30 cheaper at £115, and George gave the Santini Ombra Unisex jersey a very good review and that's 'just' £90.

If you are looking to spend a lot less, Stu rated the Van Rysel Road Cycling Jersey Racer when he reviewed it in 2022, and though as the Summer Jersey Racer 2 it's gone up a fiver, it's still only £49.99.

Conclusion

Overall, this is a stylish summer jersey that's perfect for hot summer days. The fabric does a great job of keeping you cool and the fit is excellent – if a little closer than I expected. It is quite pricey, though.

> Buy now: Isadore Signature Merino Air Jersey for £145 from Isadore

Verdict

Stylish, lightweight, highly breathable summer jersey with a great fit