tatest wrote:
You want GVWR 1500 to 2000 pounds more than empty weight of the RV. Much less than 1500, you tend to overload. A whole lot more than 2000 pounds, ride will be rougher unless you can load close to GVWR; it is not like air suspensions, which adjust actual spring weights to a ride height.
There are not a lot of differences between to two chassis. E-350 once had a taller rear axle ratio, and option for 5.4 V8 rather than 6.8 V10. Now, with same engine, performance is equal. E-450 gets stronger rear brakes for extra 2000-3000 pounds of capacity, and higher recommended inflation pressures for same size tires.
Maybe Ford cheapened manufacturing costs up over the last 10 years or so by building both chassis closer to the same?
Way back when we bought our small Class C on it's optional-at-the-time E450 chassis, here's what some of the differences were between the E350 and E450:
1. The E450's frame was made from stronger steel (either thicker, or a tougher grade) than that of the E350.
2. The E450's rear differential ring gear was a larger diameter than that of the E350.
3. The E450's driveshaft was a larger diameter than that of the E350.
4. The E450's brakes were hydraulically boosted, while those of the E350 were vacuum boosted.
5. The E450's brake swept areas were greater than those of the E350.
6. The E450 had both front and rear anti-sway bars, while the E350 came with only a rear anti-sway bar.
7. The E450 had a front steering damper shock - the E350 may not have (I'm not sure about this).
8. The E450's rear stance (distance between the right & left dually sets) was around 3-5 inches wider than that of the E350.
9. The E450's rear differential ratio was 4:56, while that of the E350 was 4:12.
The above are why we wanted an E450 chassis under our 24V Itasca instead of the E350. We wanted chassis overkill - betting that it would offer improved long-term reliability, durability, handling, and safety in both highway and off-highway use.
Our small E450 based Class C does not rock when we walk around inside it (due to it's stiffer suspension and dual sway bars), it's handling in high cross-winds and when big-rig trucks pass is minimally affected (due to it's stiffer suspension, dual sway sway bars, and wider rear stance), it's braking is rock solid on downgrades (due to it's larger brakes combined with it's greater engine braking from to it's rear differential ratio), and the transmission never overheats on uphill grades or when slow-speed crawling along off-highway (helped by it's rear differential ratio under both conditions). We can load up our small motorhome as we wish, with never any fear of front or rear over-loading.
We have taken most of the harsh ride away from the rear leaf springs (due to weight under-loading) by installing frequency selective damping shocks back there. The original OEM shocks in the front are still good after 71K+ miles and the ride from the E450's front coil springs has never seemed harsh (which is at least partially due to the geometry of coil springs as contrasted to that of leaf springs).
I'm curious ... does Ford even still make available an E350 E-Series cutaway chassis for the few builders still wishing to offer some of their Class B+/C products based on the good-old E-Series chassis? How could someone even buy a U.S. sourced Class B+/C motorhome based on an "overkill" chassis anymore other than on the E450 chassis ... since IMHO the Mercedes 3500 and crop of newer U.S. OEM sourced delivery van cutaway chassis are not much "overkill" - under even a small Class B+/C.
In the expedition vehicle world there are of course plenty of $$$$ heavy duty chassis choices available under small coaches, but where does one go for an affordable small rig that still has a degree of "over-builtness" in it's running gear? IMHO, the E450 under a small motorhome offers this combination.
