I realize that I may be an anomaly here......
But my Sabre has a Lippert frame, axles etc..
The frame is very stout, and the welds are top notch.( I am a welder).This is the first TT I have owned that I have not had to repair the frame on. Those were NOT Lippert frames
The axles were the sealed bearing type originally. When a bearing went south, and I found that Lippert had discontinued that type of axle, they fixed me up with brand new heavier axles and a VERY good price.
The point is, Lippert will sell a manufacturer whatever they ask for.
Sabre spec'd a heavy duty frame, and that is what I got.
Many other manufacturers, sadly do not... Probably to save a few bucks to be competitive....But that is NOT Lipperts fault