Cero is a Barcelona based multidisciplinary design firm based with a focus on product design, engineering, graphic design, and programming. I recently discovered them by way of their Behance page, which features a few bike projects ranging from freeride and XC mountain bikes to an urban electric folding bike. On each of the Behance project pages, they provide a glimpse into the design process of the bikes with inspiration images, sketches, renderings, and prototype photos.
In addition to Behance, check out the project pages on their website for more design and development images. In particular, the “Making of the Summum” page shows several sketch iterations leading to the final frame design. Interesting work… definitely a group of designers to keep an eye on.