That's why they supply that grease with it. Don't put it on very heavy though, if you get it on the threads and rods too thick it'll make a terrible mess when bark/dirt/sand or a combination thereof collects on it.

Seriously though, it will take a little time to break in or loosen up. What I do is simply even it out by pulling on the side that is short. You can get your fingers in both sides at the same time and wiggle it even.