If the blade slips off, it's either out of alignment or loose. It's usual for metal cutting bandsaws to have plain steel wheels. If the alignment is off, the blade would slip off rubber just as easily.
A forum member directed me to "Blade Tracking and Adjustment for 4×6 Metal Cutting Bandsaws By John Pitkin." which not only explains adjustment, but also tells you which way yo tilt the wheels!
Just google for what I put in quotes and you will find a link to the pdf. It will save many tears.
Neil