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Bontrager B1 short sleeve base layer



Lightweight, fast-drying base layer to keep you comfortable in warmer weather.

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 Bontrager B1 base layer is a lightweight, fast drying base layer that's ideal for warmer weather.

This has become my default base layer over the past few weeks. When everything is washed and ready to go, it's the one I reach for first for warm rides.

Why? For a start, it's made from polypropylene. A lot of people see polypropylene as a bit cheap 'n' nasty. It's not the softest fabric known to man but it can be made into an ultra-light base layer. This weighs just 88g and it's super-airy. It has a textured, waffly surface with only the ridges actually in contact with your skin, so it doesn't stick to you even when you sweat buckets.

Plus, polypropylene doesn't soak up sweat as such. It transports sweat from your skin out to your jersey where it can evaporate away, but it doesn't get heavy with moisture. That means that there's not a layer of damp fabric around you by the time you get to the top of each climb. Feel this base layer when you take it out of the washing machine and you'll see what I mean – it's virtually dry straightaway.

The one problem I find with polypropylene is – how can I put this delicately? – it can stink. Or rather, it provides an amenable medium for odour-producing bacteria. It comes out of the wash smelling okay but you wouldn't want to leave this base layer on for long after finishing your ride.

All the seams are flatlock stitched so you can't feel them and the cut is fitted to minimise folds and creases. There's a load of stretch in the fabric to allow for any bulges you might have.

The heat-on logos might not last the distance – the one on the left shoulder blade, for example, is starting to peel – but who cares? No-one sees them anyway.

The same base layer is available in a sleeveless version for £26.99.


Lightweight, fast-drying base layer to keep you comfortable in warmer weather. test report

Make and model: Bontrager B1 short sleeve base layer

Size tested: Medium

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Bontrager say, "Stay cool with B1, Bontrager's lightest weight baselayer. Designed to be worn as a first layer in warm temperatures, B1's ultra-light waffle knit construction reduces fabric-to-skin contact, creating air pockets next to the skin that aid in evaporative cooling.


* Ultralight cooling baselayer for warm weather comfort

* Full mesh knit construction provides excellent air and vapor permeability

* Textured surface minimizes skin contact and creates cooling air pockets next to the skin

* Polypropylene filament yarns wick moisture to keep skin dry

* Fitted cut for non-bulky layering under jerseys and jackets"

That just about covers it. It's a performance-type base layer designed to keep you comfortable in warmer weather.

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

Bontrager say, "The Bontrager family of baselayers: B1, B2, and B3. Three different fabric designs. Three different fabrics weights. All moisture-wicking, quick-drying, and featuring 4-way stretch comfort. Each tailored for specific thermal performance."

The B1 is designed for warm conditions. Bontrager say, "B1''Warm conditio. nB1's ultra-light waffle knit construction reduces fabric-to-skin contact, creating air pockets next to the skin that aid in evaporative cooling."

Rate the product for quality of construction:

The cut is good and the flatlock stitched seams are comfortable.

Rate the product for performance:
Rate the product for durability:

Polypropylene is hard wearing.

Rate the product for weight, if applicable:

It's not that the light weight is going to make you any faster but the airiness does add to the comfort.

Rate the product for comfort, if applicable:

Polyprop isn't the softest material out there but it keeps you dry and that's the real value.

Rate the product for value:

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

Very well. It stays reasonably dry no matter how much you sweat.

Tell us what you particularly liked about the product

I like the fact that polypropylene doesn't get heavy with moisture and dries incredibly fast.

Tell us what you particularly disliked about the product

In my experience, polypropylene starts to smell quite quickly.

Did you enjoy using the product? Yes

Would you consider buying the product? Definitely.

Would you recommend the product to a friend? Yes

Overall rating: 8/10

About the tester

Age: 41  Height: 190cm  Weight: 75kg

I usually ride:   My best bike is:

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

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, general fitness riding,


Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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