Alloy wheels don't need to flex, though. If a rock wedges into nooks and crannies of this, perhaps it could mess up the performance. And perhaps it could cause

Alloy wheels don't need to flex, though. If a rock wedges into nooks and crannies of this, perhaps it could mess up the performance. And perhaps it could cause damage since you'd have a harder material (rock) rubbing against a softer one (rubbery airless tire stuff).