front wheel on the passenger side that it wobbled slightly

I just replaced my rotors and brake pads and noticed when I was tightening the front wheel on the passenger side that it wobbled slightly. The drivers side does not do this. I have also noticed lately that the car seems to shake a little around 60 mph. What could this be and is it safe to drive? I have a short trip (6o mi.) to make this evening and I'm not sure if I should go or not. Thanks.