Studded tires help A LITTLE if there is a slick surface under the snow that you can't see.Wide tires and as little as 20 to 15 psi helps a lot unless the snow becomes thick and heavy.then the wide tires are hard to push.The temperature,
the consistency of the snow,what's underneath, and the tires and the required pressure all vary.You need to experiment for a given snow condition.
It can be different every day.I use Nokian 256's (studded tires) and go from 40 to 15 psi with no tire problems.I have heard of guys running 5 psi and glueing one bead to the rim to keep it on.I am considering the snowcat rims for my snow bike too.I have fenders to keep me dry and I have put them a long way from the tires,like a motocross bike,to prevent clogging.They help keep the drive train ( and me) from getting icy.They snowcat rims are double wide rims that increase your tire footprint.The studded tires and low pressure allow me to ride over the deep frozen footprints in the ice.It's a great deal of work,and slow, as is 6" of snow. 6" deep (if powdery) is about my limit. 4" is much better.Good training.I love it! Fresh powder or very hard ice is great fun.Just practice as much as possible.Be patient it's slow.Eventually you learn to control the slipping and sliding by keeping the bike upright all the time, even when turning.Don't bother to do ice much without studded tires.