I have a 2012 Shadow Cruiser 280QBS that had the axle issues that have been already stated. I spoke with Cruiser RV directly and they did take care of the issue by getting the axle manufacture involved. The axles were replaced with a 5200lb axle(s) and they replace the tires.
Based on the comments and the speculation to why this occurred, I will provide my 2 cents. We didn’t discover the axle issue until my family went on an extended vacation with a total of 2300 miles through the West Virginia Mountains and up and down the east coast. Prior to this trip we did short trips (avrg 400mile) with very little grade or winding roads. I believe under very normal condition the axles were rated properly. However, no trailer is really towed under normal conditions. I found the total length of the trailer plays a big role in how the axles perform. Since the weight of the trailer during winding road and hill driving shifts more to the rear axle, the 3500 lbs axle is not able to take the weight. Design flaw...yes. I think that a trailer under 30 ft total weight would do just fine, but this trailer goes 32ft. As far as tire wear, please keep in mind that the trailer is not stocked with radial tires. I would invest into radial tires. Also I took off the stocked stabilization jacks and put a more durable set on.
With all this said Cruiser did everything right to get this fixed no cost to me. The trailer otherwise is enjoyed by the family. Since 2012 was the first year for this model, I took a risk buying only because of the unknown science manufacture take in rating. I think Cruiser has fixed their initial design flaws and still have the best value for a QBH.