Having completed a frontloader conversion (see the write-up here) built using forged carbon lugs and aluminium extrusion, it was then time to move on to a complete new build. Named not only for it’s distinctive plumage, the Peacock was born to show off. Its design and construction was used to test and refine the construction methodology as well as showcase what is possible.
A flat bar gravel bike was chosen due to it’s relatively simple frame geometry (no rear suspension) and complete absence of suspension, giving the opportunity to design and build carbon forks right from scratch (I’ve gone into more detail on this here).
The design work started in July 2022 (mostly just evenings after work and family duties) and the build started in March 2023. In February 2023 I was lucky enough to quit my job and became a part-time dad, part-time mad inventor under the house. The bike was assembled and rolling in July 2023, then eventually tweaked and finalised in October 2023 after testing and working on some other projects.
Not wanting to rave on for too long, here’s a quick breakdown of the bike’s features:
- Bafang M510 BB integrated mid-drive motor with torque sensor. At 36V, this motor is capable of 250W (300W peaks) and 95Nm of torque and weighs in at 2.9kg.
- Custom 430Ah Lithium ion battery.
- Box Two Prime 9 extra wide groupset with 12-50 tooth cassette. A 36 tooth chainring on the front rounds out the 1x drivetrain.
- 27.5′ Mavic Crossride wheelset with bladed spokes.
- Schwalbe Marathon E Plus tyres.
- Shimano XT M8100 hydraulic disc brakes with 160mm rotors.
- Suntour suspension seat post.
- 760mm handlebars (15mm rise) and 90mm stem.
- Sweet sweet colour shift “Sonic Purple” (green/blue/purple/violet) paint job.
Overall, the Peacock was an excellent chance to further refine the forged carbon lug method for building bike frames. A number of advancements were achieved through this exercise, namely:
- The incorporation of continuous carbon strands (tow) to provide even greater strength where needed in the lugs.
- Enhanced surface finish and mould survivability through revisions to the mould design and finishing/processing after 3D printing.
- Improved precision during assembly thanks to the use of 3D printed jigs.
- More efficient use of materials around the brake side drop-outs due to using a “slip over” top brake post mount fitted on the fork blade and seat stay.
Testing has found the Peacock is performing exceptionally well and has given me the confidence to move on to building a longtail cargo bike using the same methods. Furthermore, the build process gave me the idea to combine a more typical composite construction method (hollow shell frames) with forged carbon lugs, specifically for the front triangle, to enable more creative geometries. This is something I’ll be working on to include in the upcoming longtail frame.
