Hardtail eMTBs are the unsung workhorses of the electric mountain bike world. They’re simple, tough, and they make a lot of sense if you want one bike that can commute during the week, disappear off down bridleways at the weekend, and still feel happy lapping a mellow trail centre without you constantly worrying about bearings, linkages and shock servicing. That “one bike, loads of jobs” brief is exactly where the Merida eBIG Nine 400 sits, and it’s why bikes like this have quietly become the gateway into everything from adventure riding to “trekking-style” e-bikes with racks and mudguards.

The risk with a do-it-all hardtail electric mountain bike is obvious: stretch it too far, and you end up with something that’s fine at everything but doesn’t really shine anywhere. The Merida eBIG Nine 400 avoids most of that trap by keeping the fundamentals sensible. It’s built around Shimano’s EP6 motor (a sweet spot for power and usability), paired with a big 630Wh battery for proper ride time, and a straightforward 29er hardtail chassis that’s easy to live with. It’s not pretending to be an enduro sledge, but it does have enough capability to be fun off-road. Crucially, it’s comfortable and confidence-boosting when you’re just trying to get out and ride.

There are a couple of areas where the stock build feels aimed more at summer hardpack and mixed-surface riding than full-on UK winter slop. The good news is those aren’t deal-breakers. They’re the sort of things you can sort with a smart tyre choice (and, depending on how hard you ride, a brake tweak), turning the Merida eBIG Nine 400 into a much more “all-season, ride-anywhere” hardtail eMTB.

How the Merida eBIG Nine 400 handles mixed terrain

The first thing you notice on the Merida eBIG Nine 400 is how easy it is to just get on and crack on. It’s comfortable straight away, the riding position feels natural, and the whole bike has that calm, steady hardtail eMTB vibe that encourages you to explore. This is the sort of bike you can ride from your front door, string together shortcuts and cheeky off-road connectors, and never feel like you’re forcing it into a job it doesn’t want.

On rough tarmac and pothole-strewn back roads, the 29er wheels help it roll smoothly, and the 100mm fork takes the sting out of chatter without feeling like it’s wallowing. Head off onto bike paths and towpaths, and it’s effortless, stable, predictable, and not twitchy. Once you point it at bridleways, woodland trails and light trail-centre terrain, it still keeps its composure. It doesn’t shout about being aggressive or “enduro-ready”, but it’s far more capable than the sensible, practical spec list might suggest.

Where the stock setup starts to show its limits is exactly where you’d expect in the UK: wet months, claggy mud, and that lovely combo of greasy roots and sloppy corners. The Maxxis Ikon tyres are fast-rolling and fine in dry conditions, but in sticky mud they don’t clear well enough to keep their edge. When the tyre packs up and effectively turns into a semi-slick, cornering becomes more “careful and measured” than “point and shoot”. The bike doesn’t become unrideable; it’s still stable, but you’ll find yourself riding more cautiously through turns than you’d want on a bike that otherwise encourages you to push on.

The upside is that in drier, dustier conditions, gravelly trail centres, hardpack, and summer bridleways, the Ikons make the bike feel lively and efficient. If your riding is mostly mixed-surface with only occasional proper mud, you might even like the speed. But if you’re buying a hardtail electric mountain bike to ride year-round in Britain, a tyre swap is the single best upgrade you can make.

Shimano EP6 motor: spot-on power for this kind of hardtail eMTB

Shimano’s EP6 is a strong match for the Merida eBIG Nine 400. It’s got the shove you want on climbs, plenty of torque for steep ramps and winching up loose, awkward tracks, but it doesn’t feel like it’s constantly trying to take over the ride. The support feels usable, not just powerful. That matters on a hardtail eMTB where traction can be the limiting factor, because you can modulate your effort and keep the rear tyre hooked up rather than lighting it up.

A big part of the EP6 experience is how well the power delivery works across modes. There’s enough separation between them to make mode choice meaningful, and with sensible gear selection you can get exactly what you want: either a steady, efficient push for distance days, or a more urgent “get up and over it” feel for punchier climbs. It’s a motor that makes you feel like you’re riding, not just being towed.

Pairing the EP6 with the integrated 630Wh battery gives the Merida eBIG Nine 400 proper ride potential. You’re not stuck thinking in tiny loops or constantly watching the battery percentage. For a bike that’s meant to do a bit of everything, including longer leisure rides and off-road exploring, that battery capacity is a real part of the value story.

The handlebar display/control setup is functional rather than fancy. It’s not the slickest-looking cockpit in the world, but it’s clear, readable, and easy to understand. For a bike in this price bracket, it’s a sensible trade: reliable and straightforward beats flashy.

What the Merida eBIG Nine 400 is like to ride off-road

Off-road, the Merida eBIG Nine 400 is a confidence builder. The steering is positive without being nervous, and the front end feels planted enough to let you pick a line and commit. It’s a hardtail, so you still want to ride with a bit of finesse through rougher trail sections, but it’s not harsh or punishing. The 29er format helps it carry speed and smooth out smaller hits, and the fork’s on-the-fly adjustment lets you tune the feel depending on whether you’re cruising or trying to be a bit more playful.

It’s also the sort of bike that doesn’t mind getting messy. Through woodland tracks and proper bridleway grime, it keeps doing its job. Even with mud building up, it remained rideable and predictable and that’s exactly what you want from a practical hardtail eMTB that’s going to see real-world use rather than pristine summer-only rides.

One of the nicest touches is that it’s quietly practical. The kickstand might not be everyone’s idea of “pure MTB”, but if you’re using this bike for everything from school-run duties to commuting to weekend exploring, it’s useful. The no-tool battery removal is another genuinely good day-to-day feature. And the little multi-tool tucked under the saddle is a proper “get out of jail” addition, the kind of thing you’ll forget about until the first time you need it.

Niggles, and the upgrades that fix them

The biggest limitation is still the tyre choice for UK conditions. If you want the Merida eBIG Nine 400 to feel like a more serious electric mountain bike in the wet, swap the tyres for something with more open tread and proper bite. You don’t have to go full downhill tyre, either, just something that clears mud better and gives you predictable cornering on wet roots and soft ground. A more aggressive front tyre in particular will calm the steering and make the bike feel more planted when conditions turn grim.

The brakes are another area where keen riders may want a tweak. The Shimano MT200 two-piston setup works, and I never had a moment of “no brakes” panic, but the power and bite point feel a bit soft if you’re used to sharper braking. On a heavier hardtail eMTB, that can translate into pulling the lever further than you’d like to get the response you’re after. If your riding is mostly commuting and mellow leisure miles, you’ll likely be fine. If you’re planning regular trail-centre laps, steeper bridleway descents, or you simply like a firmer lever feel, it’s worth considering an upgrade path.

A sensible, cost-effective approach is to start small: a proper bleed, better pads (depending on what’s fitted), and making sure the setup is dialled. If you still want more, moving to a four-piston Shimano brake setup is the clean “MTB” solution for a hardtail electric mountain bike like this. It’s the kind of upgrade that makes the bike feel more controlled without changing its character.

Finally, winter riding will expose any bike’s weak spots, and the Merida eBIG Nine 400 is no exception. Mud loves to collect in certain areas, and you’ll find yourself clearing clag from tight spots if you ride in proper slop. If you’re committing to year-round use, basic protection helps: a decent mudguard setup to keep spray down, and sensible cleaning habits to stop grit doing its worst.

Final thoughts: who is the Merida eBIG Nine 400 for?

The Merida eBIG Nine 400 is a genuinely useful hardtail eMTB at a price point where value matters. It’s comfortable, stable, and capable enough off-road to be fun, while still being easy to live with for commuting and everyday riding. Shimano’s EP6 motor suits the bike perfectly, the 630Wh battery gives you real ride time, and the overall package feels like it’s been put together for riders who want one electric mountain bike that can handle a lot of different jobs.

It’s not a hardcore trail weapon out of the box, and it’s not trying to be. But it is the sort of electric hardtail mountain bike that can grow with you. Fit the right tyres for your local conditions, and you’ll unlock a whole extra level of confidence and year-round capability. If you also like your brakes sharper, you’ve got a clear upgrade route there, too. Do that, and the Merida eBIG Nine 400 turns into a properly solid, ride-anywhere hardtail eMTB that makes a lot of sense for UK riders.