we have similar saws where i work.
no rubber on the wheels is normal for a metal cutting saw.
i'm not sure about the blade tension compared to a wood saw as i don't get to play with big woodcutting band saws too often
try taking the wheel that's giving you trouble and completely taking it off of the machine, and inspect the shaft it sits on and the bushing inside of the wheel.
one of the saws at my work does the same thing and come to find out, it has a bronze bushing inside of the wheel that's supposed to be the same size as the shaft ( zero tolerance fit ) but over the years it had gotten wallered out a 1/16'' bigger