There are few ways of comparing air disc brakes to drum brakes that discs don't come out on top. Still, fleet adoption rates in North America hover around 10 percent. That begs the question, are discs too good for their own good? Drum brakes get the job done, so is there any pressing need to look beyond our traditional and proven way of stopping trucks? The short answer to that question would be no-in most cases. The thing with brakes is you never really know how valuable they are until you really, really need them. And brakes never fail in any way that's less than spectacular. So, if no great need has ever arisen, you can't be blamed for dismissing the arguably more costly and heavier air disc brake systems as an expensive luxury.