I have to add something here... Road salt should be washed off the whole quad... in this case salt on the wheels would be the least of your problems. Salt in ANY form ( road salt, sea salt) is not good to leave on your quad... unless you want your quad to rust before your very eyes.Just wash it off after every ride.
One of the places I ride is Pismo Beach... The dunes are inland from the beach and are dry sand. But since the sand was blown in from the beach, it has loads of salt locked up in it. That salt is released when there is moisture... I very seldom use a pressure washer on my quad... except after riding at Pismo. Too much fricking fun to ride there, so I do the best job I can with the clean up.And then some . Thats why I dont race beachcross in the UK.