Bird's first foray into carbon is available with a ginormous 541mm reach

Bird Aether 9C is a carbon 29er trail bike with 130mm of rear suspension, a 65° head angle, 78° seat angle, 430mm chainstays and 541mm reach on XL.

>>> MBR Trail Bike of the Year 2020

bird aether 9c

Bird Aether 9C Carbon need to know

  • Full Carbon frame
  • 130mm rear
  • 130-150mm front suspension
  • 29in wheels with 2.6in tyre clearance
  • 65° head angle
  • Short 430mm chainstays
  • 484mm reach on ML size (541mm on XL)
  • BSA threaded bottom bracket
  • Size specific seat angle: 76.5° to 78°
  • Frame £1,700.00
  • Complete builds from £3,463.50

Bird Press Release

Bird have released their first carbon bike, the Aether 9C today.

Size Specific Angles

The Aether 9C is unique for Bird as it’s their only bike with size-specific seat tube angles. With taller riders needing a longer seat post, that puts them and their weight further back relative to the wheels of the bike which can create too little weight on the front end and the front wheel lifting up on steeper climbs.

The seat tube angle on the Aether 9C starts at 76.5-degrees on the size medium and steepens to 78-degrees on the size XL. Bird claims this will keep the weight distribution even across sizes. They also increased the head tube stack on each size to aid in rider fit and comfort.

Frame Details

The Aether 9C has the best water bottle clearance of all Bird’s full-suspension frames with even the smaller size accepting a 750ml bottle with a piggyback shock. In addition to water bottle clearance, the frame has room for up to a 2.6″ tire.

The bottom bracket on the full carbon frame is BSA threaded and there is fully internally guided cable routing with an internal Y-connector that allows the rear brake to be run on the left or right size. The suspension is tuned for efficient pedaling and a lively feel.


The Aether 9C is available in several different builds as well as a frame only option.

The frame alone sells for £1,700.00 It includes the rear axle, SRAM Universal Derailleur Hanger (UDH), and rubber frame protection on chainstay and down tube. All Bird frame-sets come ready to build with clean chased BB threads, tapped ISG05 mounts and axle threads, as well as a fully faced BB and headset.

Shimano 12-speed builds start at £3,786.50, and SRAM 12-speed builds start at £3,463.50.

There is a complete bike builder on Bird’s website that allows users to customize their builds from the ground up. It should be noted that there are certain items that would typically be in the store that are currently low stock which has pushed up the complete prices of bikes for the moment, however, they have plenty of kit available.