Marin Bikes | Four Corners Sora

📏Size Guide

Built for exploration, commuting, and long-distance adventures, the 2025 Marin Bikes Four Corners Sora is a steel-framed gravel and touring bike designed to take you wherever the road—or lack thereof—leads. With its classic steel ride feel, all-road geometry, and thoughtful features, it’s made to handle the demands of loaded touring or everyday riding in comfort.

This model uses a double-butted CrMo frame and fork, sized specifically to riders using either 650B or 700C wheels. The 650B version is optimized for smaller riders, offering improved fit, handling, and standover. A Shimano Sora 2x9-speed drivetrain keeps gearing simple and effective, while mechanical disc brakes and wide 47mm tires ensure confident control on pavement, gravel, or dirt.

Key Features:

• Double-Butted 4130 CrMo Steel Frame & Fork
Classic steel feel with modern geometry for comfort and durability on long rides

• Shimano Sora 2x9-Speed Drivetrain
Reliable shifting with a wide range of gears for loaded touring or off-road exploration

• Tektro Mechanical Disc Brakes
All-weather stopping power that’s easy to maintain

• 650B Wheels with 47mm Tires (Size-Specific)
Smaller wheels for smaller riders, offering comfort, control, and clearance

• Full Touring Mounts
Rack and fender eyelets, six bottle mounts, and lowrider fork mounts for complete setup flexibility

• Upright, Stable Geometry
Higher stack for better comfort and heads-up visibility on long rides

• Tire Clearance Up to 50mm
Room for even wider tires to handle rougher terrain with ease