100 Percent Jackets
100 Percent MTB Jackets carry the brand's gravity and enduro racing roots into outerwear that's built to take a hammering. Whether you're dropping into a muddy Welsh trail centre or threading singletrack on a grey Peak District morning, the range is designed around one premise: stay dry, stay mobile, keep riding.
The headline piece is the Hydromatic jacket - a fully waterproof, breathable shell with taped seams and a high hydrostatic head rating. It's built for proper downpours, not just the odd drizzle. Then there are the lighter, packable windbreaker options: DWR-coated, compressible enough to stuff into a hip pack, and genuinely useful when you're not sure whether to trust the forecast.
What sets 100 Percent apart from the sea of black shells is the cut. These jackets are shaped for an aggressive riding position - articulated sleeves, a helmet-compatible hood, and an aerodynamic drop tail that blocks rear-wheel spray without bunching up when you're tucked. Bold colourways, too, if you're done with looking like a crow on the trail. UK riders get a range that covers everything from a short evening blast to a full-day enduro sufferfest.
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Fabric Tech and Weather Performance
The Hydromatic waterproof jacket is the serious wet-weather option. It uses a laminated membrane - available in 2.5-layer and 3-layer constructions depending on the model - with fully taped seams to block water at every stitched join. The waterproof rating is high enough to handle sustained heavy rain, which matters when you're two hours into a Scottish hill loop and the sky opens properly. Breathability is the other side of that coin: the Hydromatic membrane allows vapour to escape during hard climbs, so you're not cooking inside your own shell by the top. It's never going to match a dedicated XC racing jacket for ventilation, but for the stop-start effort of trail and enduro riding, it handles the heat well.
The lighter windbreaker jackets use a DWR coating - a durable water-repellent finish applied to the outer fabric - rather than a full waterproof membrane. That makes them packable and fast-drying, ideal for showers that blow through quickly. Worth being clear on the trade-off, though: DWR sheds light rain, but it won't keep you dry in a sustained downpour the way a taped Hydromatic will. If your rides regularly end in biblical mud, the windbreaker is a second layer, not a substitute.
Sleeve panels on several models use ripstop fabric and Cordura reinforcement - practical on tight singletrack where you're brushing past gorse and brambles. It adds a little weight but extends the life of the jacket noticeably. If you've ever put a hole in a cheap shell on a thorny bridleway descent, you'll understand why this matters.
Fit, Range, and Getting the Size Right
100 Percent cuts these jackets for riders who are actually riding - not standing upright in a car park. The sleeves are articulated, so when you're leant forward on the bars, the cuffs stay where they should rather than riding up your forearms. The drop tail is longer at the back, which does two things: it covers your lower back when you're in an aggressive position, and it deflects the mud and water your rear wheel throws up on wet days. On a muddy Surrey Hills loop, that's the difference between a damp base layer and a soaked one.
The helmet-compatible hood is worth a mention - it's shaped and adjusted to sit properly over an MTB lid, not just a road helmet. Pull it on over your helmet during a stop and it actually works, rather than perching on top like a shower cap.
Sizing runs fairly true, but if you're running bulky chest or back protection under the jacket, size up. The trail-ready fit has enough room for low-profile armour without issue, but hard-shell protectors need the extra space. Pairing the jacket with 100 Percent trousers from the same range gives you a consistent fit designed to work together - worth considering if you want everything to move as one when you're pushing hard.
Looking for core warmth without the sleeves? Check out our 100 Percent Gilets. For off-bike comfort or dry-weather park laps, browse our casual 100 Percent Hoodies and 100 Percent Sweatshirts.
How does the range compare to the competition? Endura jackets tend toward a more conservative fit and strong weather performance built for Scottish conditions - a solid choice if pure waterproofing is the priority over aggressive styling. Alpinestars jackets sit in a similar space to 100 Percent, with motorsport-influenced design and durable construction. The 100 Percent range competes well on aesthetics and trail-specific detailing.
Layering for UK Conditions and Keeping the Jacket Performing
UK riding - particularly from October through to April - means you'll rarely be dealing with one type of weather in a single ride. A moisture-wicking synthetic base layer under a Hydromatic jacket is the sensible starting point: it pulls sweat off your skin so the jacket's breathable membrane can do its job. Avoid cotton entirely next to your skin; it holds moisture and gets cold fast on any descent. Pair that base layer with a lightweight mid-layer on colder days, and you've got a system that adapts as you warm up on the climbs.
Gloves and a matching kit complete the picture - take a look at 100 Percent gloves and 100 Percent jerseys if you want to keep the layering consistent. Cold hands and a warm core is a miserable combination, and it's easily sorted.
On washing: it matters more than most riders think. Wash the jacket on a gentle, cool cycle using a tech-wash designed for waterproof membranes - Nikwax Tech Wash is the standard reference point. Never use fabric softener; it clogs the pores of the breathable membrane and strips the DWR coating, so the jacket starts wetting out rather than beading water off. After washing, a low-heat tumble dry or a warm iron on a low setting through a cloth reactivates the DWR. If the jacket is beading water less effectively but still feels waterproof from inside, that's usually just a tired DWR - a re-proofing spray can bring it back without replacing the jacket.
Are 100 Percent MTB jackets fully waterproof? The Hydromatic range is, yes - taped seams, proper membrane, the lot. The windbreaker models are water-resistant via DWR, which is a different thing. Worth being clear on which model you're buying if full waterproofing is non-negotiable for your riding.
100 Percent Jackets FAQs
Are 100 Percent MTB jackets fully waterproof?
Jackets in the Hydromatic range are fully waterproof - taped seams, a proper laminate membrane, and a high hydrostatic head rating that handles sustained heavy rain. The packable windbreaker models use a DWR coating instead, which sheds light showers but won't hold up in a prolonged downpour. Check which construction you're buying before committing.
Do 100 Percent jackets fit over body armour?
The trail-ready cut has enough room for low-profile body armour without any issue. If you're running bulky hard-shell chest or back protectors, size up - you'll get the mobility you need without the jacket pulling across the shoulders when you move on the bike.
How should I wash my 100 Percent waterproof jacket?
Use a cool, gentle cycle with a tech-wash made for waterproof membranes - Nikwax Tech Wash is the go-to. Never use fabric softener; it strips the DWR coating and blocks the breathable pores. A low-heat tumble dry afterwards helps reactivate the DWR and keeps the jacket performing as it should.