A friend of mine suggested lowering my handlebars to help with uphills. So I took out the spacers, flipped the headtube, put the spacers on top, and then put it all back together. However, I think I must have done something wrong, because I took it out (just on a road) to make sure that I didn't put them too low, but the handlebars rattle whenever I hit the front brake. They're fine for everything else, but I don't really want to take it out on a trail if my handlebars are going to act weird every time I hit the front brake. It kind of makes a weird sound and vibrates slightly. They're riser bars if that matters at all. Any ideas on what I did wrong and how to fix it? Am I supposed to have at least one spacer between the frame and the headtube? Should I crank on the screws tighter? Thanks in advance.