Who'd win a fight Siberian tiger or polar bear?
It's a POLAR BEAR, the largest bear (alongside the omnivorous Alaskan brown bear the 'Kodiak bear'') and the largest land predator on earth. It can weight up to 1500 pounds, it has a bone crushing bite force (42 teeth closing down with a force over 440 psi), and takes down walruses. It's thick blubber(4 inches of it) would protect it from most major damage, and the fact that it's paws are gigantic (can rip off a head of an adult human with a single blow), means it could destroy the tiger within minutes maybe. Yes, some Siberian tigers have been known to kill grizzly bears, but a polar bear is just colossal (stands fully at upright an adult males can stands 10 feet in their hinder legs). They live in the Arctic, another factor that gives the bear the advantage - the Arctics a snowy wasteland.
(But I do still love tigers - they're awesome)
I totally agree, the polar bear is the biggest land carnivore growing to a length of around 2.5 metres which is basically just under 2 metres, so yes the polar bear would win.
Possibly, possibly not. Polar bears are quite a bit larger than Siberian tigers are, so there could be an advantage there. However, polar bears and Siberian tigers rarely, if ever, meet, so any fight between these two animals is nigh to impossible.
A polar bear could kill any tiger with ease, but these two animals would not really meet in the wild.