We put a bike rack on our 4 inch 2007 Jayco Eagle 322FKS bumper and hauled 2 bikes around with us for thousands of miles. Down to Florida, cross country etc... Never had a problem or any cracks. We left the spare tire on it. Like anything frequently check it while on the road.
Bill B. (S.E. Michigan)
2014 Keystone Cougar High Country 321RES (was 2007 Eagle 322FKS)
2007 Dodge Megacab CTD