WD-40 is frequently regarded as more of a penetrant than a lubricant; depending on the severity of the conditions (e.g.,ambient road grit and velocity), you may find that it doesn't last long as a lube. It's great for cleaning off the crud and loosening a stuck antenna, tho. Silicon spray wiped on from a paper towel (to avoid overspray on your paint) works for some; teflon-based lubes work well under varying conditions. I use the Breakfree CLP, but have to re-clean and re-lube about once a month due to a lot of airborne grit. Lke any other lube, you probably want to avoid heavier greases in cold weather, and too light an oil in hot times.