There's perfectly good reason to prohibit wheeled vehicles of any kind to take the trails into the canyon. Thank goodness! There's plenty of cycling territory available and permissible in the nearby deserts, why allow one of the natural wonders of the world to be defaced. One of the few things in this world that are truly breathtaking.
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See, this is why we can't have nice things. - - smarkinson
Where else but the internet can a bunch of cyclists go and be the tough guy? - - jdon