motorcycle sidebars do not protect legs

Several years back, some motorcycle manufacturers were settling claims by customers who suffered leg injuries while riding motorcycles. The liability theory in those cases was that the motorcycle was defective, either because it lacked sidebars that would have protected a rider's leg, or that the bars provided failed to protect the rider.

Since then, there have been at least three major studies of the subject, all of which concluded that sidebars do not and cannot protect the legs of a rider in a crash. One of the three suggested that sidebars actually make motorcycles more dangerous due to their propensity to bend onto and trap the leg. The studies demonstrate that the only effective purpose of motorcycle sidebars is to protect the bike against property damage in a case where it falls over.

The reason sidebars are not effective in protecting a rider's leg from injury in a crash is that the combination of geometry and limits on material strength mean that the forces of a crash will always bend and break the bars. As they project out from the side of the motorcycle, the sidebars are, in effect, levers. When struck by a bumper or caught on pavement, the bars pivot around their points of attachment. The force of impact plus the leverage provided by the length of the bar impose more force on the bar than it can withstand, so it collapses, exposing the leg to the same crushing forces that destroy the bars.

Manufacturers of motorcycles and motorcycle sidebars today explicitly warn that bars protect bikes, not riders. As long as they carefully do so, it seems unlikely that we will see a return to the days when a plaintiffs can win a product liability case based on defect theories related to motorcycle side bars.

John Sedgewick