I recently joined this forum as I’m working on a new bike project, and I wanted to show you the first bike we made with an engineer friend I met at work.
He’s a bike enjoyer too and proper engineer (I’m a designer and mechanical conceptor) who welded his own mtb when he was a teenage, with great knowledge and also insane mean of home making : his father is also an engineer and former rally car driver/technician with a whole workshop in his basement.
We originally decided to create a bike brand but, long story short, Covid and other things happened. We ended up cooperating in making 2 aluminium+carbon prototype road frames that he pushed further into a brand recently ! (I’m sadly not part of the project anymore but you know, life !)
Anyway, he took care of making a motor tuned bicycle jig to be able to create any geometry size for any customer and hold the frame during gluing process, looked up for parts, while I designed the bike and modeled it. I have about 14 years of experience in CAD modeling (Rhino, Solidworks, Fusion360, Blender…) including complex surface modeling and I loooove it (I recently modeled the new Yamaha-Enyring frames )
Those first sets of parts were made in aluminium casting and custom filament winded tubes with local companies. Now on his new projects for which he simplified some intersection parts, he’s using titanium 3D printing for the intersection parts.
The bike feels wonderful, super reactive (stiff winded tubes & rigid intersections) , well balanced (weight distribution) and fast as F. The TI version will be much lighter and stiffer, parts are about 1mm thick and thanks to the 3D printing process you can go CRAZY on topology optimization and shapes.
I never owned full carbon bikes or ridden high end ones to give the most precise and cured comparison, but I’d say that it compares really well, with negligible sacrifices for some benefits.
Sacrifices on the weight as you’ll get something a little bit heavier, and aesthetics if you really want a full naked carbon look. I personally love the double material style.
Quite huge benefits on the process as you won’t need any complex machined mold, curing oven, heated autoclave or press. The only remaining ‘complex’ step is the aluminium casting, but it’s something I’ve seen and see more and more falling into the “makers” domain with people literally casting parts in sand molds in their garden You can yourself use SLA printing to print a wax-resin model for DIY lose-wax casting process.
I’d say that the main interest here is indeed that the fabrication process is accessible to pretty much anyone (in terms of means of production, it still costs a bunch of €/$) and very accessible to a small team and workshop with minimum in-house toolings as all parts can be fabricated by suppliers. Breaking down the frame into stiff straight carbon tubes (that you can order from a supplier and cut at desired length) and molded intersection (that you can also metal-3D-print or attempt to mold yourself) discards the complexity of dealing with large-series carbon production means or the knowledge and skills for welding.
With some perseverance you can clearly make yourself a Bastion-like bike, simple and efficient metal intersection parts + glued tubes.
Also, If you seek information about surface modeling you can AMA, I’ll try to answer your questions as good as I can. Also, I’m currently working on a new custom build (from clay sculpting and surface modeling + mold parting on SolidWorks, to actual parts making). I was thinking about streaming that on Twitch in the near future, maybe some people could be interested, especially for surface modeling as its counter-intuitiveness is the greatest barrier to getting into it.
It’s on the first picture on which the frame is mounted with the blue tape
That little genius mfckr made it by himself from profile pipes jig to motor driving and IHM to input the geometry data.
If you want to have a sneak peek at the beast moving you can spot it several times in one of his reels : https://www.instagram.com/reel/DOlvAFPgtby/ (blond guy in the video, the other dude with the cap is a fixie comp rider. They were making his track bike version together)
The brand he created is called Cycles Arpège (instragram| website). He’s located in the north part of Paris and also went to Bespoked in Dresden, Germany. Maybe some people from here spotted him who knows. I wished so hard I could have kept going on this project
)
