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100% Hydromatic Shorts review

Yep, that’s a Boa dial on a pair of shorts! Does it help or hinder their performance?

Our rating 
3.5 out of 5 star rating 3.5
GBP £120.00 RRP | USD $139.00 | EUR €139.00
100% Hydromatic Shorts for mountain bikers

Our review

A great cut on the bike, but the Boa dial is fiddly and they're a bit snug to pull on and off
Pros: Non-flappy cut; broad waist; comfortable
Cons: Snug to get on; Boa dial closure adds little
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The 100% Hydromatic shorts join a range of waterproof items from 100%, all featuring a classy, understated, simple aesthetic.

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They’re distinct in the mountain bike shorts market thanks to their adoption of a Boa dial to fine-tune fit around the waist.

This system has a rubberised wheel that turns to pull in a wire joining the two sides of the waist, while popping the dial up releases tension.

100% Hydromatic Shorts details and specification

The Boa dial doesn’t necessarily add much to the shorts’ performance, but it doesn’t overly hinder it, either.
Russell Burton / Our Media

The Hydromatic shorts feature a slightly stretchy material with standard levels of waterproofing and breathability – with both metrics being rated at 10k (below 10k for waterproofing really indicates water resistance, rather than waterproof).

As you’d expect, seams are taped to help prevent water ingress.

The material around the seat of the short is made from a slightly thicker, stiffer material with a ripstop pattern, handy in this high-wear area.

The cut has been designed to be “aerodynamic”, according to 100%. This means it has a slimline cut that reduces material flapping in the wind.

The shorts feature two pockets on the thigh, closed with a weather-resistant zip.

The waistband is broad and features silicone grippers to prevent the shorts migrating down as you wear them.

Rather than poppers and open fly, the shorts have a Boa dial to cinch in the waist for a good fit. There’s also a mesh covering the opening, so the shorts don’t fully open out when you loosen the Boa dial.

100% Hydromatic Shorts performance

There’s enough length to protect the thigh and knee pad sock from the worst of the weather.
Russell Burton / Our Media

I like the cut of the shorts. They aren’t too baggy around the thigh, and so feel comfortable even when wet or caked in mud – excess material would increase their weight and make clamminess becomes more noticeable.

The legs are long enough to cover the tops of your knee pads, and any gap between pad and undershort.

However, they’re not so long that you can feel any annoying rubbing at the back of the knee, despite little in the way of grading the cut to favour extra length over the knee.

The broad waistband is also comfortable. It spreads the pressure of a tighter waist closure and helps prevent the shorts slipping down as you ride. The silicone grippers also work well, in this regard.

There’s a little stretch and give in the waistband, coming from the mesh panel that sits where the fly would be.

This mesh panel also regulates the amount the shorts can open up when you put them on, and in reality I found it didn’t open up particularly far – even if the Boa dial is released fully.

I found that these shorts were harder than others to pull over my thighs and backside, despite having the correct size for my waist.

100% has been banging out some great-looking kit in recent years.
Russell Burton / Our Media

While not a deal-breaker, it is a frustration especially when removing the shorts after really muddy rides, when I wanted to minimise the amount of mud transferred to my undershorts, for example.

It also makes comfort breaks a little more time consuming – I wasn’t able to just open up the shorts to use the toilet. Instead, thanks to the Boa’s wire and the non-opening fly, you have to pull the shorts down more than you would with others.

The Boa dial itself is easy to use and, thanks to its location, I’m yet to find it getting caked in mud – something I find annoying on shoes with Boa closures, for example. That said, I’m not sure it adds much to the performance of the shorts.

I found the pockets on the Hydromatic shorts to be good. They’re well located on the thigh, far enough round to the side that phones don’t hinder pedalling comfort.

However, the zip’s tags are small and harder to grab with mountain bike gloves on than other shorts I’ve tested.

I like that there’s a more durable seat stitched into the short – in testing, I noticed wear on other shorts, whereas these have remained looking fresh.

How do the 100% Hydromatic Shorts compare to the Scott Trail Storm WP shorts?

Scott’s Trail Storm WP shorts impressed in testing with their comfortable material and decent cut.
Russell Burton / Our Media

Both the shorts from 100% and Scott have a similar slim cut over the thigh, reducing flapping in the wind and clamminess when wet.

The 100% shorts are a little longer over the knee, which will suit riders with longer legs, or those who want a little more coverage for their knee pads.

The fabrics have similar performance, but I’d say Scott’s material is a touch nicer next to the skin. I also found Scott’s pocket zips easier to use with gloves, and perhaps more weatherproof too.

100% Hydromatic Shorts bottom line

The pockets on the 100% Hydromatic shorts are well-placed and a good size.
Russell Burton / Our Media

The 100% Hydromatic shorts have a great cut and decent pockets – some of the best placed in my recent waterproof shorts testing.

While the Boa’s action doesn’t hinder performance, I’m not sure it boosts it either, and the snug fit over broader areas of the body made getting the shorts on and off a touch more fiddly than other pairs.

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Overall, I like the shorts, and will continue to wear them, but technically they are outperformed by others.

Product Specifications


Price br_price, 5, 3, Price, EUR €139.00GBP £120.00USD $139.00
Brand br_brand, 5, 10, Brand, 100 percent


Features br_Features, 11, 0, Features, Sizes: 28, 30, 32, 34, 36, 38"
Colours: Black
Gender br_gender, 11, 0, Gender, Men's