RockShox | BoXXer Ultimate Electric Red D2

Stay composed when the trail gets chaotic.

The RockShox BoXXer Ultimate is a race-focused downhill suspension fork designed for riders who demand predictable speed, traction, and control on the most demanding terrain. Its new LinearXL air spring delivers a coil-like ride feel, with a supple initial stroke, supportive mid-stroke, and jounce bottom-out bumper for controlled end-stroke performance.

Exclusive to Ultimate models, ButterWagonTech maintains a constant supply of oil to the bushings to reduce friction throughout the service interval. The Charger 3.2 RC2 damper with ButterCups technology provides intuitive compression and rebound control while reducing high-frequency trail chatter and hand and arm fatigue.

Important Compatibility Note

20×110mm BOOST™ axle. Available for 27.5" and 29" wheels with 180mm, 190mm, or 200mm travel. Maximum tire width is 81mm. Maximum rotor size is 220mm, with a 200mm minimum. Bolt-on fender compatible using the separately sold BoXXer Bolt-On Fender.

Key Features

• LinearXL Air Spring
Delivers a consistent, predictable ride feel with supple initial travel, mid-stroke support, and a jounce bottom-out bumper.

• ButterWagonTech
Maintains oil supply to the bushings to reduce friction and help maintain smooth performance throughout the service interval.

• Charger 3.2 RC2 Damper
Uses rebound and compression tunes matched to the LinearXL air spring for controlled suspension performance.

• ButterCups Technology
Blocks 20% of high-frequency trail chatter to help reduce hand and arm fatigue.

• Intuitive Compression Adjustment
The numbered control bezel makes compression adjustments easy to understand, starting at "0" and allowing damping to be increased or decreased.

• SKF Wiper Seals
Low-grab seals help deliver long-lasting fork performance and a smoother ride.

Technical Specifications

• Category
Downhill Suspension Fork

• Discipline
MTB / Downhill

• Wheel Size
27.5" / 29"

• Travel
180 mm / 190 mm / 200 mm

• Damper Type
Charger 3.2 RC2 with ButterCups

• Fork Offset
44 mm / 48 mm for 27.5"; 48 mm / 52 mm for 29"

• Steerer
1-1/8" Aluminum

• Axle
20×110 mm BOOST™

• Upper Tube Type
38 mm Aluminum

• Damper Adjust
Crown

• Volume Reducer
0/6 Tokens / 1/6 Tokens

• Spring
DebonAir+ with ButterCups / Linear XL with ButterCup

• Maximum Tire Width
81 mm

• Maximum Rotor Size
220 mm

• Minimum Rotor Size
200 mm

• Fender Compatibility
Bolt-On Short, using AC-FEN-BXR-A1

• Compression Tune
C5

• Rebound Tune
R55

• E-Bike Approved
Yes

• Finish Options
BoXXer Electric Red - Gloss / Gloss Black

• Included Components
BoXXer Ultimate fork

Built from racing experience to keep the fork calm, the rider focused, and the fastest lines within reach.