Rotation Engineering requested the engineering help of DXM Design Works to design a new and improved T47 bottom bracket for high-performance mountain bike applications. We worked collaboratively to produce two design versions of the Rotation Engineering T47 bottom bracket to reach an optimized solution by leveraging a combination of rapid prototyping techniques and conventional manufacturing. The final design features an internally captive O-ring seal to prevent water ingress during muddy race conditions, tight tolerances to guarantee alignment, and an optimized spindle shield design with tight clearances to keep dirt and debris out of the bearings.