Extention Eurus C165 frame

Following the success of Extention as a street-trials brand, the C165 or Eurus, is Extention’s latest full-suspension frame and their first carbon offering in this category, marking the move beyond street-trials machines and into long-travel enduro. The frame has proven itself in Extention's domestic market - China - over the course of the past couple of years and is now being thoroughly thrashed by Arkadiusz Perin from Poland, who Extention have partnered up for the 2026 season. 

The frame is manufactured near Shanghai and is tested to Category 5, with compatibility for both single and dual-crown forks. Extention’s proprietary EVP virtual pivot suspension system is designed to provide sensitivity at the start of the stroke, strong mid-stroke support, and stable handling under braking. A detailed explanation of the EVP kinematics can be found below.

The suspension layout uses CNC-machined aluminium links to generate 165 mm of rear travel. A flip chip at the upper mount allows the frame to be run as a full-29 or mixed-wheel configuration without significant changes to geometry. Shock compatibility includes standard air shocks as well as coil shocks when using the 67.5 mm extension link.

Highlights:

• Category 5 certification
• Fully carbon fibre front and rear triangles
• CNC machined alloy linkage with machine bearings and additional dirt and dust seals
• CNC machined seat tube clamp with titanium bolt
• CNC machined Extention brake adaptor with titanium bolts
• Internally routed hosing for derailleur, brake and dropper post
• Titanium front triangle damper mounting pin with titanium bolt
• Flip chip design for 27.5" or 29" rear wheel with titanium securing bolt
• Alloy lower linkage expanding pivot with titanium bolt
• Rubber chainstay and bottom tube protectors
• Weight: 3.51kg (M)

Scope of delivery:

• Eurus frame
• 180mm and 203mm rear brake adaptor
• UDH hanger with Extention axle
• Chain guide mount
• Seat clamp
• Cable guide blanks
• Spare short Extention chainstay protector to install wherever you see fit
• Detailed service manual

From a rider-focused design perspective, the frame incorporates features intended to simplify maintenance and improve long-term durability, including straightforward access to pivot hardware, mud clearance around the rear triangle, and significant noise-reduction measures. All bolts and axles use a dual-locking interface to minimise the risk of hardware loosening or damage from overtightening.

EVP Suspension Characteristics

Extention’s EVP system uses an upper-link layout with a progressive leverage curve. The initial part of the travel is tuned to remain sensitive to small bumps, while the mid-stroke provides additional support for higher-load events such as compressions and landings. The progression is suitable for air shocks and can also accommodate coil shocks using the 67.5 mm extension link.

Anti-Squat Behaviour

The anti-squat characteristics have been designed around a sag window intended to maximise climbing efficiency without relying on excessive shock damping. Lower damping allows the rear wheel to maintain traction across uneven surfaces. When the gradient or terrain changes, the suspension remains active enough to transition effectively into descending performance.

Maintenance and Noise Management

The frame incorporates features intended to reduce maintenance requirements in muddy or harsh conditions. Pivot access, cable routing, and drainage/clearance zones have been designed to reduce noise and simplify service intervals.

Wheel Size Options

The main pivot and upper-link flip chip allow both 29” and mixed 27.5/29” configurations. The chassis can be built with a dual-crown fork when using a high-position 29” setup.