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Giant Illume Mid-Thermal Long Sleeve Jersey



Warm and breathable jersey that'll help you stand out in the gloom

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Giant Illume Mid-Thermal Long Sleeve Jersey will certainly get you noticed on the gloomiest of days, and its fabric will also keep you warm and relatively sweat-free. It offers comfort and performance for not a lot of money.

  • Pros: Impressive warmth from quite a thin material; eye-catching colour
  • Cons: No zipped valuables pocket

I'm not normally a huge fan of bright yellow jerseys as they tend to have that 'high-vis' look about them, but the Giant Illume manages to carry it off, being bright enough to make you stand out against the background while still looking like a classy jersey.

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As the name suggests, the Illume also has quite a few reflectives for riding after dark. The black armbands have fine reflective strips all the way round, which is mimicked by the rear tail gripper. There is also a reflective strip on the rear pocket and the Giant logo on the chest will also bounce the light back.

Giant Illume Mid-Thermal Long sleeve Jersey - arm detail.jpg
Giant Illume Mid-Thermal Long sleeve Jersey - tail.jpg

Giant refers to both ThermTextura and TransTextura fabric in the Illume's construction, describing ThermTextura as incorporating "all the benefits of TransTextura fabric by transferring body moisture from inside while insulating you from the cold air outside". I found it worked well: on mild days around the mid-teens centigrade I remained sweat-free even when working hard with a summer baselayer underneath. With the temperature heading towards freezing, the jersey kept me warm down to about 4°C with a long sleeved baselayer beneath. I tend to run quite warm, though, so you might need to vary your layering.

Giant Illume Mid-Thermal Long sleeve Jersey - sleeve.jpg

There is no actual windproofing or water resistance here, but that does make the Giant versatile as a three-season jersey for when the temperatures can fluctuate a bit on a spring or autumn ride if you are out for a long time.

Giant Illume Mid-Thermal Long sleeve Jersey - chest.jpg

The thinness of the fabric also means you can layer up easily with a jacket if it is cold and wet.

The fit is relatively close but not restricted to racing whippets; there's a bit of room and the shape is pretty flattering to an amateur cyclist's build.

Giant Illume Mid-Thermal Long sleeve Jersey - back.jpg

The tail is dropped to provide plenty of coverage to your rear even when in the drops, and there is plenty of length in the arms too when you are at full stretch.

Giant Illume Mid-Thermal Long sleeve Jersey - riding.jpg

The front is arched up slightly to minimise bunching of the fabric and it also stops the bottom of the zip catching the material of your shorts or tights.

Giant Illume Mid-Thermal Long sleeve Jersey - hem.jpg

There is no zip garage at the neck, but the collar isn't actually that high so irritation isn't very likely. I would prefer a slightly taller collar to stop draughts, and for it to be a little closer cut to the neck, but that's the only real criticism I have when it comes to the overall shape and fit.

Giant Illume Mid-Thermal Long sleeve Jersey - collar.jpg

Sizing is realistic, more UK than Italian, and Giant's size guide seems accurate.

The Illume has three pockets at the rear, with the two side ones angled down slightly towards the edges for easier access when you're riding. They're still plenty deep enough to stop things being ejected on rough roads and there's plenty of tension in the fabric to keep it taut. I would have liked a zipped valuables pocket for this kind of money, but it's not exactly a dealbreaker.

Giant Illume Mid-Thermal Long sleeve Jersey - pockets.jpg

Priced at £64.99 it is very similar to the dhb Classic Long Sleeve Jersey (£65) although I prefer the Giant's softer fabric and better fit. The Giant Illume feels like a higher quality product, but the dhb does get a valuables pocket and zip garage.

It's a fiver less than the very similar and also very good Lusso Terrain LS jersey.

> Buyer's Guide: 20 of the best winter cycling jerseys

Overall, I really like the Giant Illume jersey. It may be a bit basic compared to some that offer more features and more protection from the elements, but it does what it's designed to very well.


Warm and breathable jersey that'll help you stand out in the gloom test report

Make and model: Giant Illume Mid-Thermal Long Sleeve Jersey

Size tested: Medium

Tell us what the product is for

Giant says, "Featuring ThermTextura™ technology for superior heat retention, moisture transfer and quick drying, with fluorescent yellow and 360-degree reflective details to keep you visible day and night, Giant's innovative Illume long sleeve jersey provides both excellent visibility as well as superior comfort."

Tell us some more about the technical aspects of the product?

Giant lists:

Fluorescent yellow with 360-degree reflective details enhances visibility day and night

Quick drying fabric featuring TransTextura™ technology provides excellent moisture transfer

Race fit, body-contoured to enhance performance

Raglan sleeve cut provides maximum arm movement

Soft, silk-like feel

Three secure, easy-access rear pockets

Full-length auto-lock zip

UPF sun protection

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for fit:
Rate the product for sizing:

A realistic size for the British cyclist.

Rate the product for weight:
Rate the product for comfort:
Rate the product for value:

How easy is the product to care for? How did it respond to being washed?

The yellow fabric can stain if you don't wash it straight after your ride and allow the road grime to get ingrained.

Tell us how the product performed overall when used for its designed purpose

It is a very good three-season jersey that keeps you warm and sweat-free.

Tell us what you particularly liked about the product

The bright colour.

Tell us what you particularly disliked about the product

Neck could be a bit taller and closer.

How does the price compare to that of similar products in the market, including ones recently tested on

There is strong competition from the likes of Triban, but it holds its own against offerings from dhb and Lusso.

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 overall score

It may be a bit on the basic side, but it delivers on what is most important: a very comfortable fabric that is warm and breathable, a performance cut, and a decent price. Overall, I think it's very good.

Overall rating: 8/10

About the tester

Age: 41  Height: 180cm  Weight: 76kg

I usually ride: This month's test bike  My best bike is: B'Twin Ultra CF draped in the latest bling test components

I've been riding for: Over 20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed

As part of the tech team here at F-At Digital, senior product reviewer Stu spends the majority of his time writing in-depth reviews for, and ebiketips using the knowledge gained from testing over 1,500 pieces of kit (plus 100's of bikes) since starting out as a freelancer back in 2009. After first throwing his leg over a race bike back in 2000, Stu's ridden more than 170,000 miles on road, time-trial, track, and gravel bikes, and while he's put his racing days behind him, he still likes to smash the pedals rather than take things easy. With a background in design and engineering, he has an obsession with how things are developed and manufactured, has a borderline fetish for handbuilt metal frames and finds a rim braked road bike very aesthetically pleasing!

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