I rebuild the axle hubs on our our trailers once a year, and replace the brakes on the car hauler too. The axle tubes are trussed with 2"x2"x1/4" angle iron. I think the axles are in better shape than most car hauler trailers out there. Plus, I only wheel enough to take my trailer somewhere about 6 times a year (actually it hasn't moved in 2 years).
Special Thanks and Recommendations to;
PAC Racing Springs
Joint Clutch and Gear