Robert,
I didn't mean to imply that a wider dimension between the rear duals has anything to do with ride comfort. It doesn't, and we've had this discussion before.
What it has to do with is lateral stability, as it relates to the magnitude and height-location of a Class C's center of gravity and what the affects of that center of gravity are when the vehicle is subjected to side-ways forces resulting from curves, cross-winds, and weight shifting on laterally (side-ways) sloped road surfaces. As for myself, I'd never buy one of those high and narrow Class C motorhomes: Low and narrow, yes. High and wide, yes. But high and narrow - too much testing of the rules/laws of mechanics and hence restrictive in various travel situations for my tastes - when all aspects of safety are kept in mind.
Regarding handling ... I'd had no bad experiences with that in our two Class C motorhomes: We've owned a 1969 ~21-22 foot Chinook on a wide-stance GMC 1-ton dually and now own a 2005 24 foot Itasca on a wide-stance Ford 1&1/4-ton E450 dually. Both handled and handle superbly, and both rode and ride superbly in their driver and passenger cab areas.
In the front cab area (where the coil springs are) of our present E450 Class C chassis the ride is equal to or BETTER THAN my DW's high-end and heavy Lexus touring sedan. She has a bad back and has for years been able to ride in only certain vehicles for extensed time periods (we've not bought vehicles and returned brand new ones we did buy due to this). Her testimony as to the E450's front cab ride is all I need to boldly state that it's ride is superb in front due to all that weight on those stock coil springs, the stock sway bar, the classic I-Beam struts, and the stock steering shock absorber.
Where the ride IS BAD is in the rear of the E450 Class C ... due partially to an E450 being overkill on suspension stiffness versus the weight back there. It's also partially due to my making it worse by running a full 80lbs. of air pressure in the rear duallies to maximize gas mileage. Around 65 lbs. of air pressure in the rear duallies would take some of the sting out of the ride in the rear, and eventual retrofit of the stock shocks with Koni FSD shocks will also take some of the sting out of the ride in the rear.
The new design of Michelin's LTX MS2 tires on our Class C ... plus their being of a slightly taller size (than stock) - to put a taller air chamber between the rim and the road surface - have taken some of the sting our of the ride in the rear, too.
