Thanks to the 100k euro prize purse promised to anyone who pilots a Gates belt-driven bike to a World Cup DH win, belt drives and gearboxes have been a hot topic throughout the winter. Although Carbon Wasp’s Carbon Gearbox Hardtail isn’t designed to perform such feats, the brand has built it to become the perfect hassle-free winter mountain bike. We got some time on the bike and here are some first impressions.

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Designed to cope with the most brutal UK winters, the Carbon Gearbox Hardtail fits right in with Carbon Wasp’s constantly growing range of bikes – it’s one bike for many purposes. 

2025 carbon wasp gearbox headtube.jpg, by Liam Mercer

Thanks to the brand’s ability to lay its carbon frames from scratch, the Carbon Gearbox Hardtail comes with a ZS44/ZS56 headset configuration as standard, but for those who like a little more adjustability, it can be fitted with a ZS56/ZS56 configuration that allows space for an angle-adjust headset. 

There’s an adjustment in the chainstay length through sliding dropouts. This allows for chainstay lengths between 430mm and 470mm. However, as this is a belt-driven bike, you’ll need to fit the correct belt to reach your desired length. This is also where the frame splits to fit the belt.

2025 carbon wasp gearbox.jpg, by Liam Mercer

Although the frame can run Effigear and Pinion P-Line gearboxes, we’ve got the Pinion gearboxes with the Smart.Shift-equipped C-Line unit. As it’s running a Pinion gearbox, this gives Carbon Wasp the perfect opportunity to showcase its 3D-printed titanium cranks.

As for frame features, present is internal downtube storage that also makes the ideal spot to hold the gearbox’s battery and other gubbins. There’s internal cable routing, space in the rear for a 29 x 3.0in tyre, and the IS-mount rear brake mount can accommodate any size brake rotor.

2025 carbon wasp gearbox droput.jpg, by Liam Mercer

Built for the trail/aggressive trail category, Carbon Wasp is hitting all the right numbers. There’s a 65-degree head angle, a 76-degree actual seat tube angle which results in a notably steep effective seat tube – although the brand doesn’t state this measurement. There’s a 480mm reach figure on the large frame I tested.

2025 carbon wasp gearbox crank.jpg, by Liam Mercer

It's available as a frame only or as a frame and gearbox build. The brand can supply a full custom build and offer some customisation to the frame’s geometry. Without a gearbox, the frame will set you back £1,650 and with a gearbox, that’ll be £2,550.

As usual from Carbon Wasp, the Carbon Gearbox Hardtail isn’t painted. Rather, the brand opts to wrap the frame in a coloured vinyl wrap. A single colour is included in the price but you can go custom for an extra charge.

Carbon Wasp Carbon Gearbox Hardtail - First impressions

As the Carbon Gearbox Hardtail uses parts of the same modular mould that are used to form the Truffle-120, Carbon Wasp has almost effortlessly created a bike that’s cohesive with the rest of the range, both in aesthetic and ride quality. But over the brand’s 20-odd years experimenting with the material, it’s learned a thing or two about carbon fibre, and that’s present in the hardtail’s ride.

2025 carbon wasp gearbox logo1.jpg, by Liam Mercer

First and foremost, the Carbon Gearbox Hardtail (which I’ll call the ‘Hardtail’ from here on) sits very well in the aggressive hardtail category. It gets a steep seat tube, a generous reach, and a reasonably slack, but not too slack, head tube angle. Those numbers translate into a versatile machine that can be built to achieve a ride you would prefer. It can go more aggressive with a longer fork and burlier tyres, or it could go the long-distance route with lower profile tyres and a shorter-travel fork.

The bike I tested middled the two, showing off Carbon Wasp’s on-point geometry choices and its keenness to get up a hill.

2025 carbon wasp gearbox shifter.jpg, by Liam Mercer

Again, that seat tube is rather steep, which puts the rider in a rather upright position, especially with the stem as high as I rode it in. While cranking up a fireroad climb of varying gradients, the Hardtail showed little desire to break traction and needed little management of weight distribution to keep that traction in check. Again, this is a hardtail, so rear wheel grip is limited, but that’s to be expected.

Admittedly, the Pinion gearbox took a little getting used to, especially as I’ve been spoiled with SRAM’s Transmission drivetrains. It takes extra care when shifting underload, otherwise it’ll flat out refuse. It’s not an ideal solution as letting off the power then encourages a shift, but it’s a trait easily learned. On the subject of the gearbox, there is some drag present as larger teeth inside mesh with each other but, under normal riding scenarios, it wasn’t noticeable.

2025 carbon wasp gearbox seat tube.jpg, by Liam Mercer

Again, Carbon Wasp knows a thing or two about building carbon bikes from scratch, and that’s clear in the level of compliance that’s present. The Hardtail effortlessly smoothed out the fast of rough tracks I sampled it through, confidently ironing out the sting of harsher chattery impacts. The additional weight of that gearbox boosts stability here, too.

That compliance complements the brand’s geometry choices. The Hardtail took everything well within its stride while rewarding me with a fun, agile and morish experience. There’s little about the bike that I felt held me back. Of course, rear suspension would make the bike faster, but the Hardtail nails that aggressive trail hardtail vibe without missing a beat. While it loved the lumpy, mildly technical flow, I rode it over most of the time; steeper and more technical sections were dispatched with little nervousness.

2025 carbon wasp gearbox hedtube.jpg, by Liam Mercer

To touch back on that gearbox, on the descents, it shone. It’s not for everyone, but it's Smart. The shift feature almost eliminates the need to think about mid-descent gear changes. Constantly, it’s whizzing and buzzing, selecting gears before you think you need them. It’s not yet a perfect solution as it senses wheel speed and chooses a gear accordingly, exiting slow corners with a hard sprint can surprise the system, as it’s picked a low gear, predicting that it’s about to hit a climb rather than needing a harder gear for a boost in speed.

With gearboxes and belt drives being at the forefront of people’s minds, Carbon Wasp’s Carbon Gearbox Hardtail feeds the appetite for a trail-friendly, uber-versatile machine that reduces maintenance to a minimum. Whether you’re looking to disappear in the hills or rag it downhill, it’s more than up for either job, and everything in between. As long as you’re looking for a hardtail, that is. 

• carbonwasp.com

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