Originally Posted by Chance
For what it's worth, Ford specs show all F-53 frames -- regardless of wheelbase -- come with same 8'-10" rear overhang. On larger and longer motorhomes like Challengers it's safe to assume Thor has chassis extended at rear.
On shorter motorhomes like the Ace 29.2 that may not be the case. I'm not certain, but Ford specs have the standard 190-inch wheelbase chassis at just under 28 feet in length, and since the motorhome is only 29'-8" long, the difference could be made up by bumpers and bodywork.
Personally, I'd prefer the receiver being bolted directly to Ford chassis rails provided everything else was the same. Having said that, frame extensions can be fabricated as strong as needed.
It is not safe to assume any such thing.
The frame extension on my Challenger 37ND is between the axles toward the front (right around the rear of the transmission area) and not at the rear. The frame rail extension extends the wheelbase from 242 to 252 inches using the 22K chassis.
The Challengers with the 242 inch wheelbase may not have any frame rail extension, or the extension may be behind the rear axle. It all depends on the wheelbase of the F53 chassis used in the manufacturing process.