Moving to a carbon fiber drivetrain (from aluminum alloy) was a big step that we took very seriously for the Cruzbike Vendetta V20c. More than a few of our customers came to Cruzbike after they had dangerous failures of the carbon fiber fork on their standard road bike. Because our front fork is triangulated (part of a very rigid tetrahedron) we believe that a fork failure would be much less likely on a Cruzbike than any other type of bike. Nevertheless, we put our new fork (individually and also assembled with the carbon fiber chainstay and boom) through stress testing that we hope will far exceed anything you will ever ask of your V20c drivetrain. Imagine a robotic gorilla thrashing your cranks, bending your fork, dropping your bike, and slamming on the brakes--100,000 times.
The V20c passed every test (ISO 4210-6) thrown at it with no fractures, cracks, or bolt failures. Below are photos from the testing center in Taiwan. Tests included front fork bending, rearward impact test, front fork static bending test, fork brake mount fatigue test, static brake torque test, and fork steerer torsional test.
V20c fatigue test with pedal forces.
V20c fatigue test with horizontal forces
V20c assembly impact testing (falling mass)
V20c fork bending fatigue test
V20c fork static bending test
V20c fork brake mount fatigue test
V20c fork static brake-torque testing
V20c fork rearward impact testing
V20c fork-steerer torsional testing
We are pleased with these results. But keep in mind that no bike is indestructible. Maintain and inspect your equipment regularly, and please don't over-tighten your bolts. Use a torque wrench, (something like the LEXIVON LX-181 Inch Pound Torque Wrench 1/4-Inch Drive, 20~200 in-lb/2.26~22.6 Nm) and your V20c should last a very long time.
V20c torque specifications: