One of the biggest arguments you'd ever see on the internet. Many people argue that the tiger could kill the bear, and vice versa. Typically, you'd look to nature to settle this conflict but it is just as complicated in the wild. The tigers manage to kill and eat bears more often then bears kill tigers, but it is unclear in most encounters whether the tigers and bears were both healthy, or how old and experienced they were.
Siberian tiger vs Brown bear is the greatest argument since Brown vs Board of Ed.