I hauled 550 pounds of feed in mine this weekend. I just drove real careful until I could get some of the weight unloaded. The bed is rated at 500 pounds.
I bought a Ranger 570 in May, It got to where it would not go into reverse. It is BACK in the shop waiting on transmission teardown and word from Polaris on the fix. It may be my first and last Polaris! It puts a bad taste in my mouth!