[JesseK]

I'd predict that the bolts weren't properly tightened during some matches. This would cause the Versa hub holes to wear. The larger wear holes over time causes friction in later matches as the drive train is shoved from forward to reverse quickly, which would then cause this type of deformation. The sheared bolts are the evidence of the root cause -- when everything's tightened down properly, #10 bolts will not shear in a FRC drive train*. Supporting Anecdote: 118 supported their entire 140-lb robot driven by a 6-motor crab-drive in 2008 on 8 #10 bolts.

We used nylocks on our wheels every year from '08-'12, and never had an issue with bolts loosening or shearing. This year's an exception since we're using a WCD with a live axle and AM Performance wheels, hex bore (so no hubs/flat sprockets).

*This is potentially not the case in one of the rarest of use cases -- high traction full-speed impacts of two robots that hit each other square-on without backing off after impact. Teams 48 (Delphi ELITE), 68 (Truck Town), and 245 (Da Bears?) all have good experience with heavy high-traction defense, so they may have more insight.