To determine if support brackets are needed to accommodate the weight of the bikes/rack you'd be placing in the Curt RV Bumper 2" Trailer Hitch Receiver # E-100 you would need to contact Keystone and ask what the weight capacity of the rear bumper is. You could also reach out to a local fabrication/welding company and have them take a look/weld on some extra supports to ensure that the bumper can handle the weight. view full answer...