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2024 Calibre

BOSSNUT

A 27.5″ aluminum frame full suspension trail bike with upper mid-range components.

Weight33.5 lbs  
FrameAluminum
SuspensionFull, 130 / 130mm
ForkRockShox Recon Silver RL
ShockRockShox Monarch R
Wheels27.5″ Aluminum
Drivetrain1 × 12
GroupsetSX Eagle
BrakesSRAM Level T Hydraulic Disc
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Insights
Ride Feel

Based on frame geometry and build specs.

Terrain
easyextreme
Handling
nimblestable
BOSSNUT
Other Trail bikes
Gearing

A bike with lower gearing will be easier to ride up steep hills, while a higher top end means it will pedal faster down hills.

Lowest gear

(climbing)

24 mph

BOSSNUT

26 mph

Similar Bikes

Highest gear

(descending)

Sizing
SM

5'2" – 5'8"

MD

5'6" – 5'11"

LG

5'10" – 6'3"

XL

6'1" – 6'7"

🐐 Estimated

Rider Fit Notes

None yet.

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Reviews

Summary

The Calibre Bossnut is a trail bike that offers outstanding value for money, combining aggressive geometry with durable, high-quality components. It excels in downhill stability and climbing efficiency, thanks to its slack head angle and steep seat tube angle. While the rear shock may feel over-damped for some, the bike's overall performance and build quality make it a favorite among aggressive riders.

Pros
  • Excellent aggressive geometry

  • Outstanding RockShox and Shimano spec for the money

  • Proven dropper post as standard

  • Durable build kit

  • Great ride quality for the price

Cons
  • Rear shock is over-damped for general riding

  • No chainstay protection

  • Heavy weight

  • Brakes lack sensitivity and power, particularly in wet conditions

  • Harsh feel over smaller stutter bumps and rough sections

Key Quotes
Calibre’s new Bossnut is an outstanding mix of sorted handling and geometry in a seriously tough frame that’s begging you to ride it flat out straight away.
Bike Perfect logoBike Perfect
It’s amazing value for money too, but the tune will split opinion between senders and smoother riders.
Bike Perfect logoBike Perfect
the new Bossnut looks a lot more like something, say, Cannondale would produce
MBR logoMBR
The original Calibre Bossnut could. Launched in 2015 in the UK, it reset expectations of what a budget bike could do.
Pinkbike

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Singletrack World
Best MTB of the Year: Calibre Bossnut

Jan 2025 · Ben Haworth

The first thing I want to make clear about our MTB of the Year for 2024 choice is: this is not just because it’s cheap. It’s not even because it’s cheap and decent. The Calibre Bo…

Highs
  • Great geometry

  • Good suspension

  • Unbeatable value

  • Super efficient geometry

  • Super punchy and responsive suspension feel

  • Shimano TC500 hubs which seem to roll for days

  • Excellent handling

  • Decent build kit

  • External cable routing makes maintenance and parts swapping/upgrading easier

  • Tubeless ready wheels

  • Well chosen Maxxis tyres for all-round trail duties

Lows
  • Not UDH

  • No chainstay protection

  • Price fluctuation

  • Front brake power could be better

  • Low BB height prone to pedal strikes

  • Drivetrain roughness in extreme top and bottom gears

  • Supplied handlebar rise may be too low for some

Read Review

Bike Perfect
The all-new Calibre Bossnut is a fantastic comeback and only a shock tweak away from being a totally awesome budget full-sus MTB

Oct 2024

The affordable mountain bike market has never had more excellent, new, or 'old stock sold cheap’ options than it does now. So is the all-new Calibre Bossnut a straight to the top comeback? Guy Kesteven has been putting the hours in to tell you exactly what you need to know about this awesome affordable all-rounder

Highs
  • Excellent aggressive geometry

  • Outstanding RockShox and Shimano spec for the money

  • Proven dropper post as standard

  • Quality contacts points

  • Full XS to XL size range

Lows
  • Rear shock is over-damped for general riding

  • No UDH dropout or chainstay protector

Read Review

MBR
All of this for just £1,500? Calibre's Bossnut is back, with more travel, bigger wheels and a higher quality frame - MBR

Oct 2024 · Alan Muldoon

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. 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. 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. 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. 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. So, to recap. Calibre offers the Bossnut in five frame sizes, …Continue reading »

Highs
  • • Great ride quality for the price

  • • Dialled geometry and sizing

  • • RockShox suspension components

  • • Durable build kit

  • • MX conversion for shorter riders

Lows
  • • No chainstay protection

  • • Slightly overdamped suspension

  • • Spokes in rear wheel lost tension

  • • Aggressive riders will want a better rear tyre

  • • Needs a higher rise bar

Read Review

Pinkbike
First Look: 2025 Calibre Bossnut - The Budget Boss Is Back

Oct 2024 · Seb Stott

Though designed as a trail bike, Calibre say it's built to last, with redesigned tubes intended to strengthen every part of the frame.

Read Review

Geometry
Specs
Build
Frame

6061 Hydroformed alloy frame, tapered headtube, forged rocker link, 130mm travel, 12 x 142mm bolt through rear end

Fork

Rockshox Recon RL Solo Air 130mm, alloy tapered steerer, 15 x 100mm Maxle, gloss black with fast black stanchions

Travel130mm

Spring TypeAir

Shock

Rockshox Monarch R, custom tune, 130mm travel, 190 x 51 eye to eye, gloss black.

Travel130mm

Headset

FSA No. 57E Orbit tapered

Stem

Calibre 45mm length, 31,8mm bar

Handlebar

Calibre Alloy, 780mm length, 30mm rise, 31.8mm OD

Saddle

Calibre Trail

Seatpost

Calibre Alloy, 30.9 x 350mm

TypeRigid

Pedals

Plastic platform test pedals

Groupset
Rear Derailleur

SRAM SX Eagle

Crank

SRAM SX Eagle Powerspline, 170, 32T

Shifters

SRAM SX Eagle

Cassette

SRAM 12 Speed, 11 - 50T

Brakes

SRAM Level T

TypeSRAM Level T Hydraulic Disc

Wheels
Rims

WTB ST i29 TCS 2.0

Front Hub

Formula 32H, 6 bolt

Rear Hub

Formula 32h, 6 bolt

Tires

WTB Vigilante High-Grip Comp, 27.5 x 2.3 front. WTB Trail Boss comp, 27.5 x 2.25 rear

Rider Notes
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First added July 17

Last updated October 19

Not listed for 587 days