SRAM has created a number of new crankarm prototypes in conjunction with Autodesk that use generative design to attempt to maximize their properties.
What is generative design? Well, rather than starting with a drawing of what they believe a product should look like, the designer instead defines the parameters needed for the final result - for a crank arm that might be its length, strength, weight, Q factor and construction method (forged vs 3D printed). These parameters are then entered into a computer software, in this case Fusion 360, and thousands of potential designs are generated in just a few hours. SRAM isn't the first mountain bike brand we've seen use this technique and there have been similar experiments in design optimization from Robot
in the past few years.
Autodesk claims these designs are unlike any a human could come up with and SRAM has now selected a number of them to prototype for real-world testing. Forbes reports that
, "The end results from the design team employ differing materials of construction, and vary from something that still looks quite a bit like any other crankarm, but with significant portions of material removed, to a futuristic design that resembles a structural truss."
SRAM chose to focus on the crankarm because, unlike other areas of the drivetrain, it has remained generally identical to the version we were riding when the sport was invented. It's a structural component, so it has to be safe, but SRAM believed there was an opportunity to reduce the weight if it was approached in a new way. The titanium truss pedals in the video above certainly look lighter than conventional cranks but we don't currently have any concrete numbers on them, other than that they are apparently able to handle up to 10 g of force.
The method doesn't just remove material but it removes time from the process as well. By reducing the steps involved, its claimed an engineer can go from the design phase to the final product more quickly, and that ultimately means a cost-saving over the course of the R&D process.
At the moment, this is all early prototyping and there's no guarantee that it will be taken forward into a real-world product. Instead, SRAM is using it as a learning experience for its future product developments. Will King, Senior Design Engineer at SRAM, said, "We design products to get to the podium in the Tour de France, or to hope for medals in the Olympics. This helps us get to the finish line faster and more educated—to see where material needs to be, and where it can be removed. Generative design has a great app for our traditional construction materials, helps us understand loads and constraints, and pushes ideas we can evaluate.”
Basically, while the more unorthodox designs the software has generated are unlikely to ever be stocked on shelves, SRAM may be able to produce lighter, stronger and cheaper cranks in the future because of its experimentation. We look forward to seeing what real-world results come from this very cool partnership.