Custom Bike Frames

The perfect all-rounder, our tough, versatile aluminum frames are hand built in Portland, Oregon and can be set up with a wide range of drivetrain, wheel and cockpit types to form the foundation for a gravel-ready all-road build or a functional and fun city bike. Our modular assembly process gives you infinite flexibility for personalizing your frame with color and component choices and the precision machined surfaces will turn heads wherever you go.

Founder : RICH FOX

“I wanted to help bring back American bicycle manufacturing, even if it meant re-thinking some of the sacred cows of tradition”

Our build process balances machine precision with fine craftsmanship.

The precision Thru-Axle dropout option is a perfect complement to the clean lines of flat mount hydraulic disc brakes.

Every surface of our precision-machined lugs are thoughtfully considered to balance form, function and process.

Our horizontal dropout option is built for versatility. The 132.5mm spacing lets you build with almost any drivetrain including derailleurs, single-speeds, internally geared hubs, and even Gates belt drives.

Almost everything on our frames is sourced in the USA.

The CIRCA precision CNC’d bottom bracket shows an unyielding attention to matching process, beauty and function.

Have a story you want to tell? Our custom laser graphics and design services can make it happen.

CIRCA Color Palette

Anodized Finish Options for 2023. CIRCA’s durable, weatherproof anodized finishes are tougher and lighter than paint. Our proprietary construction process gives you the ability to map accent colors to individual elements of the frame with limitless possibilities.



  • Light, tough, smooth-riding 6061 aluminum tubing.
  • Durable, weatherproof anodized finishes stay beautiful with minimal care.
  • Standard, long-reach or short reach geometry available.
  • Stock and custom laser graphics packages available.
  • Can be outfitted to be anything from a Gravel-ready AllRoad to a stealthy belt-drive commuter.
  • Plenty of fender clearance for foul-weather riding.
  • Versatile design lets you choose your drivetrain type (internal vs. derailleur vs. single speed) as well as your bar type (drop, flat, etc.)
  • Gates Carbon Belt Drive compatible (when paired with horizontal dropout option). 
  • Sloped top-tube reduces standover height and is comfortable for all genders.

Additional Details:

Seatpost: 31.6mm

Bottom Bracket: 68mm, threaded, standard English

Fork & Headset: Tapered IS41/28.6 IS52/40 

Dropouts: 12mm Thru Axle or QR

QR Rear Dropout Spacing: 132.5mm (allows wide range of drivetrain options)

Thru Axle Rear Spacing: 142mm

Max Tire Widths: 38c for 700c. 40c for 650b.

Pricing: Starting at $2,300. Please inquire for the specifics of your build.




Contact us to discuss your build and fit requirements. If you’re in Portland, we can arrange a personal visit to our downtown studio.



We’ll work together to refine the details of your build, from fit to component selection, colors, finishes and laser etching



Your bike or frame will be built to order in Portland, Oregon and can either be picked up in-person at our Portland, Oregon studio or we’ll ship it to you.

We're here to help!

If you have any questions or are ready to get yourself on a CIRCA, please submit a contact form.