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
Make and model: Isadore Signature Merino Air Jersey
Tell us what the product is for
Isadore says: "Breathable merino jersey made for intense training on really hot days for the natural feel of natural materials."
Tell us some more about the technical aspects of the product?
Isadore says: "The main material is a blend of synthetics and with a high merino content. It is perforated, breathable and quick-drying. The back panels, sleeves and pocket area are made of Polartec® Delta™ material with 3D structure and lyocell content. It is very light, elastic, characterized by quick-drying properties and cooling effect. Smooth feeling of natural materials in contact with the body is enhanced by the increased merino wool content, 3D fabric structure and flat seams. The jersey features 3 spacious back pockets, one zippered pocket and reflective logos on the front and back. One-way recycled zipper is covered with a flap and zipper garage that protects the bibs and leather from abrasion."
And lists these details:
Perforated two-component main material with a blend of recycled polyester and Lycra
Polartec® Delta™ with lyocell on back panel, sleeves and under back pockets with 3D structure for efficient moisture wicking and cooling effect
Created for tough performance in hot conditions
Fit offers a medium level of compression
Made in the EU
Rate the product for quality of construction:
8/10
Rate the product for performance:
9/10
Rate the product for durability:
8/10
Rate the product for fit:
8/10
The fit was great, if tighter than I was expecting.
Rate the product for sizing:
7/10
I tested the medium and it was fine, though at the smaller end of the range.
Rate the product for weight:
8/10
Rate the product for comfort:
9/10
Rate the product for value:
4/10
Expensive for a summer jersey, even if it is very good.
How easy is the product to care for? How did it respond to being washed?
Washed at 30°C with no issues, and dries very quickly.
Tell us how the product performed overall when used for its designed purpose
It was great, I wore this on the hottest of days and it did a good job of keeping me cool.
Tell us what you particularly liked about the product
The fit was excellent and it was very comfortable.
Tell us what you particularly disliked about the product
The price.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
At £145 this is quite expensive for a summer jersey that you'll only wear for less than half the year.
The Castelli Endurance Pro 2 Jersey is £30 cheaper at £115; the Santini Mirage jersey received a good review and is priced at £90, and Stu rated the Van Rysel Summer Jersey, which is now £49.99.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes – although there are cheaper summer jerseys out there.
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
It's an expensive summer jersey, but it is very good. It is highly breathable, it looks great and the fit is excellent.
Age: 35 Height: 178cm Weight: 73kg
I usually ride: Specialized Roubaix My best bike is: Cervelo S3
I've been riding for: 10-20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: road racing, touring, club rides, general fitness riding, Indoor
Oh, the grifters have arrived. Don't let them in, keep the door locked shut. They get only paid to divide people and won't stop finding things to...
Agreed, plus there is nothing in the construction and materials that makes them worth anywhere near $72, maybe $20 tops.
Traffic chaos after car transporter gets stuck at narrow corner...
The A103: the choice is, parked cars that are rarely used or cycle lanes.
1. Bicycles don't have speedometers....
in the UK the DVLA will ask the worst offenders to prove they are fit to get their licence back....
I am pretty sure you don't apply the same unrelenting unforgiveness to yourself. But I don't know why it is so.
If you start with just honesty there's half a chance that there is someone in the party who is honest....
Ours has just supended the chief constable apparently. https://www.gloucestershirelive.co.uk/news/gloucester-news/gloucestershi...
Indeed. Britain's Alex Yee—who is fresh from medalling in the Paris Olympics—is the most successful male triathlete in Olympic history (two Gold...