X-Bionic The Trick Biking Pants



Well fitting and comfortable bib shorts, but you pay a lot for the clever sweat-managment tech

Cycling loves a Bit Of Science. Whether it's the aero gains to be obtained through the optimisation of your sock length or the increasing prevalence of power meters, it seems we're ready to be convinced by what the scientists say. That must have made it an obvious market for the Swiss-Italian clothing manufacturer X-Bionic, whose The Trick Biking Pants use almost baffling amounts of technology – and certainly seem to do... the trick.

X-Bionic started out making posh socks for runners, but the application of science has always been key to its products (and its marketing). As we saw in the jersey we reviewed recently, there's an almost bewildering range of trademarked and patented technology with, once again, the management and movement of your sweat being a primary focus.

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As with the jersey, the bib-shorts – sorry, I can't bring myself to call them "biking pants" – have an unusual knitted construction, with the yarn comprising 78% polyamide, 16% polypropylene and 6% elastane. It makes for an unusual feel, without the silkiness you get in conventional high-end Lycra.

Once on, I didn't find the coarser fabric irritating, and the much lower number of seams compared with multi-panel Lycra bibs is definitely a plus point. Like the Howies Leadouts, these bibs are woven almost as a single piece of fabric, with the only seams being on the inside of the legs and where the bib straps join the back panel. Seams down the inside of the leg can sometimes be a source of irritation but they've been well positioned here, fore and aft of the area where they'd rub.

Leaving aside the sweat management tech (much of which is basically the same as the matching jersey) for now, the most unusual feature here is how X-Bionic has integrated the pad. The pad itself is proprietary to X-Bionic and called the Endurance4000FX. It's a variable thickness chamois, which is divided into three separate pads that can flex relative to each other. The rearward two are thicker with a rather nice textured fabric giving very good breathability. 

The unusual bit, though, is that the pad is sewn into a hole in the bib-shorts, rather than inside the Lycra.

X-Bionic says this means the pad is perfectly positioned to give optimised fit and comfort. A further benefit is that "the fit and elasticity of the pad is not affected by the pant material", which seems an odd claim to me as the material that bib-shorts are made from is always miles more elastic than the pad, in my experience. In any case, the pad worked well for me and it was indeed in the right place. It looks a little unusual from the rear, particularly because of the contrast with the surrounding material, but hey, we don't wear bibs because they look so good, do we?

Let's talk about sweat, then. X-Bionic has developed several technologies specifically for dealing with it. "Sweat is energy,' it says. As with the jersey, there's an area of thicker knitted material along the spine. The Trick, as it's called, can fool the body into producing sweat earlier; not just along the spine but all over. In tests I found that it seemed to work, too - I noticed that I needed to drink more fluids when I was wearing X-Bionic gear on a long ride.

Making you sweat is just the start, though. X-Bionic has incorporated other fibres to move the moisture from your sweatiest bits to the areas that need the cooling effect of the sweat's evaporation. X-Bionic has named this sweat-transporting technology Thorny Devil, after an Australian lizard whose unusual skin can transport moisture towards its mouth. These fibres are helpfully orange in our test bibs, so it's fairly obvious that the idea is to move moisture from the back and belly to the thighs.

The idea is that this keeps the muscles from getting too hot and allows them to perform at their optimum. It sounds plausible even if the effect is likely to be a small one - I can't say it was something I was really able to measure, lacking laboratory conditions in which everything else was kept constant. Still, it's an interesting concept and one that's unique to X-Bionic.

X-Bionic has applied The Trick to a gilet as well as its jersey and these shorts, although I'm not sure whether it envisages all three being combined into one outfit for maximum spinal warming - do the three layers of spinal insulation make you faster than if you only wear one? And that outfit would set you back £530; some might find that sends a chill down the spine!

As I found with the jersey, the bib-shorts are the sworn enemy of Velcro. All those clever woven patterns and different coloured threads make for a bit of a mess on the inside. There are loose sections of orange thread of up to an inch in length, a bit like those you find inside socks where different colour threads are used. Okay, no one sees the inside of the bibs when they're on, but I can't help thinking it's a weak point, especially at this price.

I wasn't a fan of the bib straps - they are relatively narrow and with quite chunky seams along both sides. I prefer a wider strap to spread the load and a lightweight mesh for forget-it's-there comfort. Some high-end bibs do away with seams on the straps altogether, either bonding the edges or using laser-cut fabric to remove any source of irritation.

In conclusion, these are very well fitting bibs with an unusual woven construction and some unique technology. I found them comfortable for rides lasting a whole day - the fundamental requirement for bib-shorts - although the straps weren't to my taste.

The unusual installation of the pad might be seen as a solution to a problem that didn't really exist, and the performance gains of the sweat management are hard to quantify, but in this elevated price bracket, having some unique selling points is a good idea to differentiate yourself from the likes of Assos, Rapha and Castelli. For those with deep pockets and in search of novel marginal gains, these could be a good option.

If you're not a fan of orange, they're also available in black/white and black/grey.


Well fitting and comfortable bib shorts, but you pay a lot for the clever sweat-managment tech

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Make and model: X-BIONIC The Trick Biking Pants

Size tested: Black / Orange, Men Size L

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?

X-Bionic says: "Your circulation always directs your blood supply where it needs to go. X-BIONIC® THE TRICK® Bib Tight does that same thing with your sweat. For maximal thermoregulation while biking. Because whoever doesn't overheat has extra power for top performance."

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

Material composition:

78% Polyamide

16% Polypropylene

6% Elastane

Rate the product for quality of construction:

Highly intricate construction with some novel features. A bit messy on the inside and very prone to snagging.

Rate the product for performance:

All-day comfort thanks to a good pad; performance-enhancing benefits of the patented sweat management technology are harder to quantify.

Rate the product for durability:

Fabric is hard wearing, as long as you don't catch a thread or let it anywhere near Velcro.

Rate the product for weight, if applicable:

On a par with most other bibs, which is a little surprising as the knitted construction would suggest they'd be heavier.

Rate the product for comfort, if applicable:

Novel approach to pad seems to work well – kind of the opposite of the Castelli Progetto approach, which allows the pad to move separately to the outer layer. I'm not a huge fan of the bib straps, which are relatively narrow with quite chunky seams, but at least they stay in place well.

Rate the product for value:

These are the second most expensive bib shorts we've ever reviewed on They have innovative ideas and are well put together, but I have other lower-priced bibs that I prefer.

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

Pretty well – they're comfortable enough for you not to think about them. The Trick does appear to accelerate sweating – the claimed performance benefits are harder to test.

Tell us what you particularly liked about the product

Good pad, good fit.

Tell us what you particularly disliked about the product

Garish looks, narrow straps with prominent seams, price, looks a mess on the inside.

Did you enjoy using the product? Yes

Would you consider buying the product? No - the price is insane

Would you recommend the product to a friend? Maybe

Overall rating: 8/10

About the tester

Age: 37  Height: 190cm  Weight: 78kg

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: road racing, time trialling, cyclo-cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking


Jez spends his days making robots that drive cars but is happiest when on two wheels.  His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding. 

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