Redesigned by the world’s fastest racers, for the world’s fastest racers, you want BoXXer in your corner. The all-new 38mm chassis is equipped with the DebonAir+ twin tube air spring that will have you thinking it’s a coil. Paired with a Charger 3 RC2 damper tuned for downhill speed, BoXXer Ultimate takes you straight to the top step of the podium. And with our new crown adjustment lines, setup is a breeze—no rulers required.

Key Features:

NEW 38mm chassis designed to meet the needs of the world’s fastest racers with balanced stiffness and ride quality
NEW DebonAir+ twin tube air spring strikes the perfect balance between butter-smooth small bump feel, added support throughout the travel, and taller ride height for confidence when things get steep
NEW Signature colorway BoXXer Electric Red with an all-new graphics package
NEW RockShox premium fender compatibility (RockShox Bolt-On Fender included with purchase)
NEW Lightweight machined and anodized crown for premium looks and durability
NEW Crown height gradient creates a visual guide to simplify setup, no ruler required
Charger 3 damper tuned for BoXXer’s updated chassis and spring. Featuring High Speed Compression, Low Speed Compression, and a revamped Low Speed Rebound, every click is meaningful and exact. This allows the rider to tune to perfection with every click.
ButterCups block 20% of high-frequency “trail chatter” to reduce hand and arm fatigue, leaving you feeling fresh with more control
Ultra-low-friction SKF wiper seals provide long-lasting fork performance and improve overall suspension feel
Maxima Plush damping fluid reduces friction and silences damper noise
Maxima Plush Dynamic Suspension Lube reduces friction, lasts longer, and enhances suspension performance ride after ride

Specifications:

WHEEL SIZE - 27.5", 29"
TRAVEL (MM) - 180mm, 190mm, 200mm
STEERER - 1-1/8" Aluminum
AXLE - 20x110mm BOOST™
SPRING - DebonAir+ W/ButterCups
FORK OFFSET - 44mm (27.5"), 48mm (27.5"), 48mm (29"), 52mm (29")
MAXIMUM ROTOR SIZE - 220mm
UPPER TUBE TYPE - 38mm aluminum
MAX TIRE WIDTH (MM) - 81
MINIMUM ROTOR SIZE - 200mm
E-BIKE APPROVED - E-bike Approved
DAMPER TYPE - Charger 3 RC2 W/ButterCups
VOLUME REDUCER - 0/6 Tokens, 1/6 Tokens
COLOR (FS) - BoXXer Electric Red - Gloss, Gloss Black
FENDER COMPATIBILITY - Bolt On - Short
WEIGHT (G) - 2880
WEIGHT BASED ON - 200mm, Short Crown (Weights same for 27.5" and 29")

From World Cup downhill courses to secret test tracks, the new BoXXer builds on a legacy of speed. Built on its high-performance pedigree, the latest BoXXer was redesigned top to bottom to win races—or simply chase your buddies down the mountain. We set out to deliver the best possible balance between stiffness, compliance, and comfort for maximum control. Meet the all-new BoXXer.

IT ISN’T ALL ABOUT THE NUMBERS

It’s about giving you the control and feel you need to choose any line. BoXXer’s 38mm upper tubes are just the beginning. Through extensive riding and testing, we tuned the stanchion wall thickness and lower leg architecture for stiffness that accepts steering input without beating up your hands.

CHARGER 3 RC2

What sets Charger 3 RC2 apart from other dampers is the truly independent High Speed Compression (HSC) and Low Speed Compression (LSC) damping. With a reimagined valving design, Charger 3 RC2 is a complete revolution in damper tunability. Every rider can find their sweet spot within the precise and meaningful range of adjustments. We promise.

BUILT TO HANDLE THE PRESSURE

BoXXer’s new DebonAir+ twin tube design is unlike any air spring we’ve made before—and it rides that way. Off the top, BoXXer is impossibly responsive and supple, but it wants to eat when the big square-edged hits start coming.

SMOOTH IS FAST

BoXXer’s bushings get thirsty, so we found a way to keep them constantly lubricated as you pound through the roughest runs: each upper tube has oil flow ports to circulate more lube through the bushings.

CROWN JEWEL

The new crown height gradients create a visual guide to simplify setup, no ruler required.

ELECTRIC RED

Our new signature colorway—BoXXer Electric Red—comes with an all-new graphics package.

Occasionally, without notice, manufacturers change product design and/or specifications.

Suspension Forks Sizing

A new suspension fork is one of the most noticeable and worthy upgrades you can make to your mountain bike. A higher quality fork will be able to deal with more difficult terrain, remaining composed on the trail and keeping your wheel in contact with the ground. This gives more grip, and therefore a more confidence inspiring ride.

Not all forks are made equal, there are some very important size and compatibility aspects to look at first.

Compatibility

Wheel size

There are a few different wheel sizes for mountain bikes. 26”, 27.5” (650b) and 29” are the most common.

There is also plus (+) and fat versions available. If you are not sure it should be written on the side of the tyre.

Whatever wheel size you have, the fork must be designed to suit.

Fork steerer

The fork steerer is attached to the fork crown, this comes up through the frame and headset to be clamped at the top by the stem.

Most modern bikes will have a tapered steerer, this is 1.5” inch wide at the fork and 1 1/8th inch at the stem. Some DH bikes and older mountain bikes will suit a straight 1 1/8th inch steerer.

It is easiest and best if the replacement fork has the same diameter steerer to fit into your frame and headset.

If you are unsure on the size, drop the forks out from the frame and you should be able to see straight away if the steerer is tapered or straight.

Axle size

If you are planning on using the same front wheel with your new fork, the fork’s dropouts must suit your wheel.

The width of the front hub has traditionally been 100mm, with either a 9 or 15mm axle. With a 9mm Quick Release (QR), a fork could be described as 9mm x100mm or QR to fit. A larger 15mm bolt through axle is more common on higher end bikes, a fork could be described as 15 x 100 to suit. This 15mm axle can be a quick release style and can be referred to as 15QR

Over the last few years, a wider 110mm spacing known as “Boost” has become the new standard, this is not available for 9mm QR axles and would be shown as 15mm x 110 or 15mm Boost.

20mm axles have been common on DH bikes for some time. Although DH wheels will be 110mm wide, they are not always “Boost”. There is a new DH Boost for front wheels and forks, this means the hub is still 110mm wide, but the disc rotor/mount sits 5mm out.

For more on MTB wheels see our full guide here

Travel

The amount of distance the fork can move vertically is referred to as travel (shown in mm). The frame manufacturer will have designed the bike around a certain amount of travel. The general rule is to stay with this. Increasing or decreasing the fork travel can result in the geometry being severely compromised, making the bike handle worse than intended and putting more stress on the headtube structure.

*Changing fork travel can void frame warranty from the manufacturer, please check with the manufacturer before any travel increase/decrease.

As fork travel increases so can flex, to combat this a triple clamp design is used for forks with over 180mm of travel. The hub plus the two crowns creates a triple clamp. The forks are for DH use.

A triple clamp DH fork, travel is measured from the lower crown to the top of the fork lower legs

Offset/Rake

The distance the axle is offset from the steering axis. This directly affects the “Trail”. Trail is the distance between the contact point of the tyre and where the steering axis hits the floor. The shorter the offset the longer the trail and vice versa. Wheelsize also affects trail. Larger wheels have a longer trail. With the popularity of 29er MTB’s, there is often an offset choice to be made.

The most common offset for a 29er fork is 51mm, however, fork manufacturers offer shorter offsets to increase trail.

Fitting

Once the correct fork has been chosen there are a few things you should know before fitting.

Crown race – Slid down over the steerer is the crown race, these are usually particular to the headset on your bike. They create a seat for the lower bearings of the headset to sit on, this should be removed from your forks and slid into place on the new fork steerer before installing the new forks.

Star Nut – Inside the steerer tube there is a star nut. This has a wedge design allowing it to be slid down into place but not slid back up. There is an internal thread that takes the top cap bolt allowing the forks to be held in place and allowing adjustment of the pressure on the bearings.

Steerer length – A new fork will have a long uncut steerer, this will more than likely need to be cut to match the length of your original forks, however, it can be cut longer or shorter if you wanted to have more adjustment for stem height.

Setting Sag

See our full guide to setting sag here

Rear shock buyers guide >

Won't Be Beaten

RockShox BOXXER Ultimate Charger3 BOOST 52 Offset Debonair 29" Fork