First thing's first, you now have much heavier and much larger wheels with a fraction of the rubber to support the bumpy roads. It's going to be a rougher ride.
Second thing is, check the box or reciept for the hub size, or some call it the bore size. That's the size of the hole in the middle of the wheel. That hole is supposed to be the same size as the axle so that it fits snugly instead of having a big gap. Tat helps support the wheel, and takes load off the lug studs, thereby reducing some vibration.
If you can't find the bore/hub size, call the place that sold you the wheels. Having the wrong sixpze center bore isn't a show-stopper, but it definitely helps. I accidentally bout the wrong bore size, and I don't have much of a vibration.
I also HIGHLY recommend you get a steering stabilizer....I'm about to offer a dual-shock custom setup to tyf members for around 200-250. Worth its weight in gold....
B