15' Keystone Hideout 28BHS - rear bumper attachment

Thank you for your responses. I agree on the OEM carrying capacity, but a ST225/75/15 will weight close to 100lbs, and bikes even more when applying the torque load.

I should have stated this is a project for next year after I am out of warranty. I am not looking to put 600lbs on the back, just want to see if anyone has used the existing square tubing from Keystone when putting on a rear hitch and/or platform.