Good quality spacers are safe, unless you have a performance vehicle with a ton of torque, or something that handles well that you push hard. I believe 1 inch is the smallest you can get. The good ones slip over your lug studs has recessed pockets like your rims for lug nuts, and are machined to fit on the hub so all the weight isn't on the studs. Then they have full length studs mounted through to bolt the rims to. They can be very useful and are reasonably affordable, but they have their place and are not for use on certain vehicles.
