Harvey... do you know if Lippert builds different qualities of frames for different body builders??
Jim,
Around 2006 NuWa, struggling to remain profitable in a very competitive RV market flirted briefly with Lippert frames under their least expensive line, the HH II and a few Discover America trailers identified as "three digit models" such as 327, 329. They continued to buy frames from Young's Welding, their local fabrication shop and long time frame supplier for half the DA line and all Champagnes, their premier line.
I had the opportunity on more than one occasion to walk around and inspect bare rolling frames from Youngs and from Lippert in their storage yard on a weekend when no one was around. The difference in designed strength, construction methods, materials, and finish painting was dramatic. Youngs frames were robust and powder coated. Heavier metal, more reinforced members, and better finish. Lipperts were sparse and rough painted. An engineering degree was not required to detect the difference in quality.
My opinion turned out to be accurate over the next several years. There were some weld failures around suspension framing and lots of running gear failures. NuWa stopped sourcing frames from Lippert after the quality control issues became clear but stood behind their warranties. There were some unhappy owners and a few trailers traded in for different models.
During that period NuWa regional sales managers and spokesmen continually repeated the company mantra that "Lippert frames were built to NuWa specs" and claimed that Youngs Welding could not keep up with their demand. I assume the Lippert design specs were true but there was clearly a business reason for sourcing some from Lippert. I think it was cost savings not supply issues.
In my opinion Lippert builds lower quality frames using marginally skilled welders and lighter gauge steel and fewer frame members but they probably build what the RV manufacturer wants. Every RV manufacturer surely has one or more engineers on their payroll who specify frame requirements. Lippert and the RV manufacturer probably agree on design capacity and cost. Lippert axles, hubs, brakes, and bearings are usually sourced from sources other than Dexter and other quality US manufacturers. I believe they use ChiComm running gear. Perhaps some of their frames are equipped with Dexter running gear. The frame buyer probably decides.
We've read some failure reports here in TDR. One member several years ago wrote an account of pulling his Forest River brand trailer with Lippert frame into a state park RV parking area. One of his axles separated from the frame on one side and swung around under the trailer. The spring shackle welds failed at the attachment point on the frame. He provided photographs and discussion. I think it was a Cardinal brand but don't remember. A search should turn up his long thread. Ultimately I think the manufacturer repaired it but he was upset and no longer had much love for the brand.
Many owners continue to defend Lippert products. Each to his own.
Personally I would not buy their frames and running gear.
Credit for my initial understanding of the issue goes to my good friend Bill Stockard. Bill had owned HitchHiker trailers back in the early '90s and knew far more than I did about them. When I became interested in a new fifthwheel in 2006 I either asked Bill about HitchHiker trailers or Bill suggested I consider HitchHikers. I don't remember which. Bill knew and warned me that Youngs had been the quality frame supplier for NuWa trailers since the beginning but NuWa had begun sourcing some frames from Lippert. I investigated and learned I didn't want a unit with Lippert frame and running gear.
My HitchHiker uses a quality powder coated Youngs frame and has been very well built and reliable.
That's my opinion on the subject. You can do your homework and decide for yourself. You know more than most of us about trailer suspension, brakes, bearings, etc.
Attention: TDR Forum Junkies 
