After a four year hiatus the Calibre Bossnut is back. It’s got bigger 29in wheels, more travel and now comes with a dropper seat post fitted as standard. Yup, the price has crept up to £1,500, but as I found out, it’s still worth every penny.

The all-new Calibre Bossnut hasn’t lost any of its charm

2025 Calibre Bossnut need to know:

• Sleek alloy frame with modern geometry and 135mm travel
• Fork travel is now 140mm
• Five frame size: XS is 27in, S to XL 29in
• 29in bikes, also MX compatible with aftermarket MX link
• Two tool mounts under top tube
• External cable routing for rear brake and drivetrain
• Boost bolt-thru axles front and rear
• Spare parts, made in Sheffield

Frame and geometry

One look at the new Bossnut frame and it’s crystal clear that Calibre had upped its game. Now, I’m not implying that the old bike wasn’t cool, it’s just that the new Bossnut looks a lot more like something, say, Cannondale would produce, and not what you’d expect from what’s essentially an outdoor equipment supplier. That new aesthetic is a direct result of Calibre switching production facilities, and having a desire to move the needle once again in the entry-level full suspension category. And move the needle it has. Which is impressive given how many generations of Calibre Bossnut we’ve tested and highly rated since it came out in 2015.

The 2025 Calibre Bossnut has the numbers to match high-end trail bikes

Let’s take a quick look at the geometry and sizing for example. Yes, it’s longer, lower and slacker than before, but more importantly it’s vital stats are right up there with cutting-edge trail bikes like the Canyon Spectral and Specialized Stumpjumper 15. Albeit a 16.84kg version. There’s simply no avoiding the weight penalty on more affordable bikes, especially if they are built to be ridden hard.

Five frame sizes, two wheel sizes, all’s that missing are MX options!

And in this instance, entry-level doesn’t mean dumbed down. The Bossnut gets a 64.4º head angle for improved steering stability. A steep 77.1º seat tube angle to put you in a better position for climbing and a longer reach and short stem to improve the overall fit. In fact, it’s got all the numbers you are looking for in a modern trail bike. It’s also got external cable routing, so swapping out parts and upgrading is super easy for the home mechanic. Granted it’s not as clean or as sleek as having internal cable routing, but the second major plus point is there’s zero cable rattle.

With a Shimano Cues 10-speed drivetrain the Bossnut has the gears to keep spinning

And because the Bossnut is designed as a trail bike, Calibre has made the switch to full 29in wheels, even though every previous generation Bossnut rolled on 27.5in wheels. It hasn’t forgotten its roots, however, or shorter riders, so the XS size rolls on smaller 27.5in wheels for a better overall fit. Calibre also appreciates that some riders may need more tyre clearance, so it’s also producing a longer MX shock extender, right on its doorstep in Sheffield, for correcting the geometry when converting to an MX setup. MX links will be sold separately.

The new suspension layout on the 2025 Bossnut delivers 135mm travel

So, to recap. Calibre offers the Bossnut in five frame sizes, S to XL are all full 29in, and the XS is full 27.5in. And while I’d like to see the two smallest sizes come with MX wheels as standard, I also appreciate that there are limitations to what can be achieved on a £1,500 budget.

There’s nothing budget about the way the new Calibre Bossnut looks –  just don’t call it a Cannondale Habit!

Suspension

The old Bossnut had 130mm travel front and rear, and the new bike gets a 140mm fork and 135mm out back. And when it comes to prioritising the budget, Calibre has really focused on the suspension components. Going with a RockShox Recon fork and Deluxe shock not only guarantees a certain level of performance, it improves the overall reliability of the bike. Also if anything goes wrong with the suspension parts, they aren’t going straight in the bin.

Sag gradients on the RockShox Deluxe shock make setup easy

At 85kg in my riding kit, I was running the rebound damping on the RockShox Deluxe Select R shock wide open, and it felt just right for not getting bucked on jumps etc. If you want a more poppy playful feel however, or if you’re a lighter rider running lower shock pressures, you’re going to struggle to get the rebound damping fast enough. I set the sag to 27%, where the gradients on the shock body made it really easy to know where you’re at in the travel.

Bolt-thru dropouts front and rear boost stiffness and security

Leading the charge is the 140mm travel RockShox Recon fork.  It’s plush and reactive, even when running slightly higher pressures to keep the front end up. But it also has that low-speed catch feeling in the rebound, that I’ve touched on before. So it can feel like the damping is holding the fork down deep in its travel for a split second longer than desirable. Also, I had the rebound damping fully open on the fork so there’s no easy workaround.

The RockShox Recon fork is plush, even if sluggish to return

Thankfully, it still matched the behaviour of the rear suspension perfectly, so the bike felt really balanced. And that slightly overdamped suspension feel has been pretty consistent on all generations of Bossnut I’ve tested, so it could just be that on the cheaper shock you can’t have a light enough rebound tune and still get enough compression damping. But I’m just guessing here.

Components

It’s no mean feat decking out a bike for £1,500 without leaving some gaping holes in the specification, but Calibre seems to have done just that. Even the metal, X-Fusion remote lever for the dropper post feels reassuringly solid and shouldn’t break if your bike falls over. It also has a really light action, just like the Shimano Cues 10-speed drivetrain.

Even the X-Fusion metal dropper remote feels high-end

I really liked the feel of the mushroom-style lock-on grips, and while the profile of the handlebar felt good, it could do with more rise, as I was running almost the full stack of spacers under the stubby stem to get the bar high enough.

The 2025 Calibre Bossnut is fast and fun in equal measure

The Shimano Cues 10-speed drivetrain offers a 11-48t gear range and while it still has that annoying chain rumble in the lowest gear when grinding up the steepest climbs, the shift action is both light and precise. Yes, there’s a pronounced delay in freehub engagement, but that’s a totally acceptable compromise on a £1,500 bike.

Twin-piston Shimano brakes are super reliable

Shimano also supplies the twin-piston brakes. And just like the RockShox suspension, they aren’t going to end up in the workshop bin at your local bike shop one year on. Also the braking performance was 100% consistent, with none of the BS variable bite-point problems you get with Shimano’s Servo Wave brakes. To get the most from these basic brakes though, you’ll want to reposition all of the controls so you can shove the brake levers inboard, just so you can use one finger right on the end of the lever to maximise the mechanical advantage. Also, heavier riders may want to upgrade to 200mm rotors for increased stopping power, even if the rear tyre is probably the real limiter here.

Maxxis tyres as standard, but the Forekaster likes predictable conditions

High-volume Maxxis tyres round out the package and while I’d like to see something with a little more bite on the rear than the Forekaster, just for better traction in mixed conditions, the dual compound Maxxis tyres definitely keep the tempo high on rolling singletrack and blacktop. Something to consider, if you’re just getting into mountain biking and your fitness isn’t quite where you want it to be. And while you can hear the firmer side knobs pinging of roots and rocks like an unwanted backing track to every ride, they ping predictably, so you can still maintain a really good degree of control.

The spokes in the rear wheel came loose after one ride

In fact, the only problem I had with the build kit was that all of the spokes in the rear wheel worked loose after just one ride. The front wheel was fine, but the rear wheel needed some serious attention with the spoke key. Once tensioned though, the spokes didn’t work loose again. So it’s something worth keeping an eye on, as you don’t want to detonate your rear wheel on landing, just because the spokes were loose. The best solution would be for Calibre to get the wheels pretensioned better before the bikes leave the factory.

No chainstay protection. So you’ll need to get it covered pronto.

In four days of riding, not one single component part really bugged me on the Bossnut. Yes, a good rider will be able to outride some of the components, but that’s just part of the fun. Actually,  I tell a lie, the chain slap is seriously annoying. And if you’re really strapped for cash, I’d do a ghetto tubeless conversion with some Gorilla tape, then wrap one of the inner tubes around the chainstay for protection.

On the ground and in the air, I instantly felt comfortable on the Bossnut

Performance

Getting a bike before the official launch meant that I really got to grips with the new Bossnut. And with a few tweaks to the set up, it didn’t take long for me to feel confident to hit all of the trails I usually use for testing at full tilt.  Thankfully the conditions were dry out, as the tyres would have made some of those trails wild in the wet.

Climbing

Sit and spin and the Bossnut just plugs away on the climbs. The steep seat tube angle put me in a good position for climbing, and the combination of the 32t chainring and 11-48t cassette gave me a low enough gear to winch up most gradients. Even traction was better than expected from the Forekaster rear tyre, but like I mentioned before, the conditions were dry. Stand up, however, and start mashing on the pedals and the swingarm extends slightly due to the chain forces, which can mess with your rhythm and traction. It could also be why the shock has slower rebound damping, as it helps mitigate this particular trait. Or maybe, I’m overthinking it, and it’s just how shocks feel at this price point. Still, the climbing position is really good, so if you relish the ups just as much as the downs, the Bossnut won’t disappoint.

Descending

There’s no doubt in my mind that the Bossnut was designed for the fun stuff. On flowing single track or typical trail centre trails, the Calibre Bossnut is an absolute flying machine. In fact, on the Blue Steel trail in Sheffield, the 29in wheels and harder compound tyres really allowed me to keep rolling and even build momentum, without constantly having to throw in pedal strokes to maintain speed. I even managed to hit a couple of doubles that I initially thought were way out of reach.

Blue Steel and the blue aluminium frame, what a combination

But it’s not just a point and shoot, straight line missile. Linked turns felt really good, and the Bossnut still has that whippy feel to the frame, just like the old one, where the flex feels like it enhances the ride quality, rather than detracting from it.

Get the Bossnut on more natural, rooty, tech trails however and there’s work to be done on the suspension and tyres. The rear suspension could be more supple off the top at lower speeds, but start smashing into stuff and the rear end is very effective at absorbing bigger hits and really helps you maintain all of your speed. And even when I hit some sketchy drops, I still had some travel in reserve, so there’s good progression in the linkage too. With that in mind, maybe I could reduce the shock pressure a touch, and increase the sag to 30%. But then I’m always tweaking.

The 2025 Calibre Bossnut definitely won’t hold you back

And while I’m nitpicking subtle traits of the suspension, I was only able to do so because the geometry and sizing put me in such a commanding position that I could easily ride the Bossnut hard enough to uncover these limitations. But then again, this bike isn’t designed with the more experienced rider in mind, it is designed to be upgraded as you gain that experience, and want to push even harder. So in that respect, Calibre has absolutely nailed the next generation of Bossnut, for the next generation of shredders.

Calibre is back and the Bossnut offers the complete package, dropper and all