Ordered two of these wheels/tires after deciding to get rid of the air tires on the cart. I changed both tires/rims at the same time. Although they initially appeared fine once mounted on the axle, one of the new wheels/tires was seriously out of round when I first put the car under load. In particular, the axle box within a wheel arch is misaligned or broken in such a way that lateral vibration occurs. I'm out of shape enough to feel resistance or reach through the cart handle. I'm not good at showing the problem with pictures so I'll make a video and post it here soon. What was the charge you ask. A bale of alfalfa weighing no more than 100 pounds, if that. Evenly distributed, that's 50 pounds per wheel/tire. Note: no, the axle is not curved, it is straight.