I don't like wd-40 for anything but cleaning/water removal. For lubrication I always hit my bearings with Slick 50 One Lube. It's the bomb...if you can find it. According to the manufacturer, only Ace hardware, True Value hardware, and NAPA have ordered any in the last year. I think I'm going to have to stock up and get 3 or 4 cans in case they quit making it all together. I've been using the same can for the last 10 years, but it's about empty now.
I don't use water to clean my RC cars, I use compressed air. You don't have to remove anything before you blow it off, and you don't have to wait for it to dry. You just blow, and go.