One of my interests outside of work is mountain biking. Being a patent attorney, I inevitably love the technology that goes into bikes too. In the case of one innovative bike company, Atherton Bikes, this interest overlaps with one of my professional interests, additive manufacturing.
The story behind Atherton Bikes is remarkable. The company was founded by the Atherton family, a sister and two brothers who have all been mountain bike world champions. After spending years developing bikes for their sponsors, the Athertons started their own bike company to design, make and sell their own bikes. This has given them the freedom to try something different to the usual way of making bike frames.
Forming bike frames from metal works well for the complicated parts where stresses are also concentrated, such as around the junctions between the tubes making up the frame. That said, carbon fibre is generally favoured for bike frames due to a better strength-to-weight ratio. However, carbon fibre works better for simple shapes, and requires complicated lay ups and forming to accommodate design requirements such as tube junctions and the mounting points for suspension linkages.
Atherton Bikes use carbon fibre tubes bonded to metal lugs in an innovative way. Previous attempts along these lines have not done well because the lap joints were often a point of failure. Atherton bikes have looked to Formula 1 and aerospace engineering to take inspiration to solve this problem. Atherton Bikes form their lugs by additive manufacture using titanium powder, which allows 3D printing the lugs to allow double lap shear joints with the carbon fibre tubes. Put simply, the lugs have double walls at each joint to form a socket that receives the carbon fibre tube. This allows both the inner and outer surfaces of the carbon fibre tube to be bonded to the lug, greatly increasing strength over traditional single lap joints.
The use of additive manufacture brings other advantages. The lugs are strengthened by printing internal ribs that cannot be formed with conventional manufacturing processes. The use of additive manufacture allows a large range of lugs to be formed and bonded to carbon fibre tubes that can be cut to any desired length. This flexibility allows a greater range of bike frame sizes: Atherton Bikes offer 22 off-the-shelf sizes compared to a more usual range of 5 or 6 sizes, and they even offer a bespoke service where the customer can specify their own sizing and geometry. This flexibility and speed of manufacture also greatly benefitted development the bikes. Typically a new frame will go through many iterations as refinements are made to geometry, sizing, suspension layout, etc., and Atherton Bikes could turn around a refinement to their frame designs in under a week.
I would have loved to have been involved in this project from a professional point of view. One of the best parts of my job is the initial meetings with new clients where you learn about their business, start reviewing their intellectual property and work through a plan to protect that IP based on their current situation and how they expect to grow in the coming years. My professional curiosity means I have looked for any patent applications publishing in the name of Atherton Bikes, but I have not seen any to date despite all their innovations. Hopefully there are some out there, either as yet unpublished or filed in a less obvious name. I am not sure how well this method of manufacture would scale to the economic mass production needed by the big brands in the bike world, but I hope Atherton Bikes don’t end up giving away their innovations to competitors for free. Patents are there to protect all the hard work and expense that goes into developing stand-out products like their bikes, and it is a shame to see such innovation not receive the full reward it deserves.
Frame construction principles Our Atherton Bikes engineers come from F1 and aerospace backgrounds and are known for being at the forefront of additive manufacturing and composite technologies. We’ve channeled their learnings to create a strong, durable and lightweight MTB frame from bespoke carbon fibre tubes joined to additive manufactured titanium lugs.