IamTymURnot wrote:
Yeah, there is a separate sheet that lists the towing weight at 3500# and for an E450 with a V10 that has to be de-rated. Does this mean that de-rated takes into account the distance behind the axle, etc.?
Thanks,
Tym
That 3500# limit is probably just due to the receiver they installed. Ford says full factory limits stay intact if the extensions were done properly. Those limits include 10k towing, rear axle weight rating, and maintaining 32% of total wight on the front axle. Ford does not have a fixed tongue weight limit, however the rear axle limit is easy to exceed (same with front axle off-loading), sometimes even without weight hanging off the hitch.
The RV makers are free to make their own limits. Forest River (including Coachmen) now retain the full Ford limits but I'm not sure if that was always the case. I believe Winnebago has a 350# vertical limit but I don't know if that is a structural limit, or if they are attempting to prevent axle overloading. When they do de-rate the chassis, there should be a sticker above the hitch (assuming it hasn't been removed).
My suggestion: take your rig to a fabrication shop for an evaluation. RVs of your era didn't always fully follow Ford's frame specs, so there may be merit to a lower limit. Keep in mind that even if nothing is at risk of failing, excessive frame flex can cause RV body problems like leaks from body joints and windows, since chassis flex can cause joints to pop open.
