Unchained Bicycles - Proto V1 5

This started as a side project between Axel and me. We got tired of derailleurs and chains, so we decided to build our own bike from scratch, here in the Swiss mountains.

The kinematics and geometry are inspired by modern enduro benchmarks, but tuned to feel like a magic carpet in rough terrain while still offering enough support to stay playful. A key goal was to keep the bike’s behavior predictable throughout the travel, so we aimed for anti-squat and anti-rise values consistently around 100%.

The bike runs a belt drive, with a novel tensioning system that maintains constant belt tension throughout the suspension travel.

The frame is entirely made from 7075 aluminum, using CNC-machined lugs and a bonded construction. The rear triangle was specifically optimized for compliance and can be tuned further with interchangeable bridges between the chainstays.

We’ve just come back from Finale and are really happy with how the bike performs in real conditions. EFBE Cat. 5 testing is also scheduled for June.

Current build is a size L, with a size M coming soon.

Some numbers:
Reach: 475 mm
Stack: 640 mm
Chainstay: 440 mm
Head angle: 63.5°
Seat angle: 77.5°

Weight: 17.8 kg (size L, race ready with pedals, enduro tires, inserts, sealant, coil shock, and a 213 mm / 34.9 mm seatpost). 

V2 development is now complete and production is underway. It will feature a concentric pivot suspension layout with adjustable rear center, allowing changes from 440 mm to 460 mm using small spacers, without changing the belt length. By swapping the rocker, it can also be converted into a 220 mm travel DH setup.