Archived Models

Ursa 29plus Steel

The CHUMBA URSA 29plus led the way as one of the first production plus bikes on the market. Backcountry bikepacking, plus bike racing, trail riding, rocks, sand, & snow: The URSA 29plus has you covered. The URSA 29plus frame offers incredible versatility and industry leading drivetrain and tire clearance! 2019 and some 2018 models used a Boost 148x12 frame with a simple 73mm BSA BB. Early models used 150x12 or 157x12 Superboost to a DH 83mm BSA BB. Compatible with up to 100mm forks.

Rastro 27plus/27.5” Steel

The Rastro uses oversized tubes throughout the entire frame, the burly chain and seat stays stay compliant on landings and keep the wheel planted and the bike tracking. A custom yoke with integrated ISCG-05 tab. The Rastro Boost model was designed to start with a wide rim and run everything from 27.5" to 27plus x 3.0”. The 142x12 model was designed for 27.5” up to 2.4. Boost models were based around 150mm travel forks and early 142x12 models based around 140mm forks.

Ursa Major Titanium Fatbike

Our trusted URSA Major Backcountry models have been tested worldwide by our team of riders. The geometry is designed for all year riding, providing confidence in your front end handling w/ a rigid fork or suspension. It's short chainstays and high bottom bracket are equally at home on the rockiest trails and deepest powder. True 5.0" tire clearance, 197x12 or 190xQR, 100mm BB. Compatible with up to 100mm forks. Also fits 29+.

Ursa Major Steel Fatbike

The URSA Major steel sets a new standard for steel fatbikes with its ultra short 435mm chainstays, 197 thru axle stainless sliding dropouts and class leading standover clearance. Designed for compatibility with either a rigid 483 axle to crown for or a Bluto 80/100mm suspension fork. 4.8” tire clearance, 197x12 or 190xQR, 100mm BB. Compatible with up to 100mm forks. Also fits 29+.