It really does tick every box

Product Overview

Overall rating:

Score 10

Calibre Bossnut EVO


  • Unmatched build kit and ride quality.


  • BB height could be lower.


Calibre Bossnut EVO (2018) review


Price as reviewed:


>>> Buy now: Calibre Bossnut Evo Mountain Bike at GoOutdoors for £799.20

Calibre Bossnut Evo

Calibre Bossnut needs no introduction. It’s now in its third iteration the latest Calibre Bossnut Evo version has moved things forward once again.

calibre bossnut evo

Calibre Bossnut EVO review

It’s no secret that Calibre had a batch of early Bossnut V1s where the rear tyre could buzz the back of the seat tube when the suspension bottomed out on big drops or jumps. The issue was cause by a batch of frames where the forward shock mount was welded too far up the downtube, throwing the suspension linkage out of whack.

>>> The best mountain bikes under £2,000

By introducing stringent manufacturing controls Calibre had fixed this once and for all, our test bike sporting 20mm of clearance between the rear tyre and the back of the seat tube at full bottom out. No doubt helped by the introduction of the kinked seat tube design on the latest model.

Calibre has also added a stealth port on the back of the seat tube for an internally routed dropper post. And in a belt and braces fashion the Bossnut retains the cable guides under the top tube for externally routed droppers.

The most obvious change though, is the switch to a 1x drivetrain. Out goes the old 2×10 Shimano Deore setup, in comes the SRAM NX 11-speed gearing, the 11- 42t cassette combined with a 32t chainring to offer a comprehensive gear range. By far the biggest advantage of the 1x drivetrain though is that you’re not constantly dropping the chain, the bike is now blissfully silent too so all you hear are your tyres carving the trail.

calibre bossnut evo

Stiffer bolt-thru Recon RL fork with low-profile axle


A less obvious advantage of the single ring set-up is that it brings the chain line closer to the main pivot, which in turn means the Bossnut Evo pedals and climbs more efficiently.

The 130mm rear suspension feels more dynamic than before too, so maybe RockShox has made some running changes to the Monarch R shock. Normally we’d have to run the rebound wide open on the Bossnut, but we actually had four clicks of rebound damping on our test bike, so lighter riders will now be able to achieve the correct rebound settings too.

And it’s not just the rear suspension that’s got better, Calibre has also improved the front suspension fork; the RockShox Sector Silver fork replaced by the latest Recon RL, which gets stiffer lower legs. It’s still 15mm both-thru with no QR lever though, so you’ll need an Allen key to remove the front wheel. Not that we’re complaining, this fork is stiff, easy to adjust and has the best damping on test.

calibre bossnut evo

Wide-range 11-speed cassette for this 1x set-up


One of the key components that always gives the Bossnut a distinct edge, especially when it come to cornering, is tyre choice. With a chunky WTB Vigilante up front you can simply rail every turn. And now that Calibre has upgrade the rear tyre from the low-profile WTB Beeline to the meatier Trail Boss, braking and climbing traction are on another level. Interestingly, the Trail Boss is still a 2.25in tyre, but it seems to measure up wider than the Beeline so get more volume too.

Tyre profiles front and rear have also been improved by switching from 25mm to 29mm rims, a move that allows you to run lower tyre pressures while maintaining tyre stability.

And if that weren’t enough, Calibre has also replaced the Richey Trail handlebar for a wider 780mm Kore bar with a much better profile.

calibre bossnut evo

You’ll never run out of cable guides with the Bossnut


It’s easy to forget what a great bike the Bossnut is, but after just one ride on the Evo it all came flooding back; the Calibre is a total ripper. Granted the geometry could be a touch slacker and lower, but that’s just us being ultra picky because every other aspect of this bike is standout. The Shimano brakes offer ultimate control, the suspension is best in test and the bike feel solid and surefooted without ever feeling dull or heavy. All of the subtle tweeks to the specification are positive and taken together the Evo version of the Bossnut is better than ever.

calibre bossnut evo

What’s new for 2019?

“The original Bossnut proved that £1,000 gets yo a great full-suspension bike. But after seeing how it was being used, abused and even raced, I wanted to move it forward again; hence the Evo. We’ve added shorter stems, a wider bar and 1x gearing. The geometry also got longer with more rear tyre clearance, all while maintaining the sub £1k price.” Mike Sanderson, senior developer, Calibre Bicycles.


calibre triple b

Calibre Triple B £1,399

The Calibre Triple B takes the stock Bossnut frame and puts it on steroids. It’s still got 130mm travel but a stiffer bolt-thru 142x12mm rear end takes it to the next level. To reflect the burlier frame construction, fork travel gets pumped up to 140mm with the lightweight RockShox Reba RL. The final piece of the puzzle is a Tranz X dropper post.

calibre line 10

Calibre Line 10 £749

Read the full review of the Calibre Line 10

Not sold on the additional complexity and weight of a full suspension bike, and would prefer an aggressive hardtail with an equally good specification? Then the Calibre Line 10 is just the ticket. With long, slack geometry, a 120mm travel RockShox Recon fork, great tyres and a dropper post, it’s got everything you need straight out of the box.


The 2018 Boosnut Evo doesn’t have the best geometry in this test; that honour goes to the Jamis Dakar A2 with its steeper seat angle, lower BB height and longer reach measurement. But a bike is so much more than a set of numbers on a geometry chart. The Bossnut Evo gets the best tyres, the best brakes, the best cockpit, and most importantly, the best suspension performance. Taken together, that’s a really tough combination to beat, and end result is that the Bossnut Evo is still the best full suspension bike for a penny shy of £1,000.


Frame:6061 T6 aluminium, 130mm travel
Shock:RockShox Monarch R
Fork:RockShox Recon RL, 130mm travel
Wheels:Formula hubs, WTB ST i29 rims, WTB Vigilante/Trail Boss 27.5 x 2.3/2.25in tyres
Drivetrain:Samox Trail DM 32t chainset, SRAM NX 1x11 r-mech and shifter
Brakes:Shimano MT500, 180/160mm
Components:Kore Durox 780mm bar, Calibre trail 45mm stem, Calibre trail seat post, WTB Volt Sport saddle
Sizes:17.5, 19.5, 21.5in
Weight:15.03kg (33.14lb)
Size tested:19.5in
Head angle:67.3°
Seat angle:70.8°
BB height:345mm
Front centre:720mm
Down tube:680mm
Top tube:622mm