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Chance · 01-14-2022, 07:17 PM

Quote:

Originally Posted by ducksface

Unless shored up by tightening everything to the nth degree, it will only add to body roll.
Irs requires low profile tires and a low butt to ground ratio.
Add the pendulum of a RV seat 5 feet off the ground and it becomes a carnival ride.

.....cut.....

I believe it is more about (avoiding) added costs than anything else. Most luxury diesel pushers have independent front suspensions which are often rated at up to 20,000 pounds (more than plenty strong). And while most DP and commercial buses (also IFS) lean considerably compared to autos and SUVs, drivers and passengers rarely complain. When Houston Metro buses came into Park-and-Ride lot where I picked up my wife, they did a tight 180-degree turn and would lean over 10 degrees or more. I asked my wife if it concerned her that the bus could tip over and she replied that she had not noticed anything out of the ordinary.

For a motorhome the added cost for independent rear suspension is even less justified because people ride close to front where front suspension makes biggest difference.

There have been motorhomes built with semi-trailing-arm rear suspension in the past, and most get great reviews for ride quality compared to traditional solid axles (given same time frame). Obviously solid axle trucks ride better today than 50 years ago, but I would expect similar improvement for IFS and IRS as well.

The Classic FMC motorhome used for On the Road With Charles Kuralt was a gasoline pusher with fully independent suspension. A much smaller motorhome with semi-trailing-arm IRS was the VW Vanagon. Also, Al-KO modifies (upgrades) Mercedes Sprinter chassis in Europe for motorhome use, and one of the main features is replacing Sprinter solid axle with semi-trailing-arm independent rear suspension.

Just saying I wouldn’t write off IRS benefits too quickly. Even if it leaned a bit more in turns, the benefits in ride quality should be well worth it. And for what it’s worth, in my opinion the biggest improvement manufacturers could make to motorhomes is to reduce their height. That would solve a lot of problems including leaning and harsher ride.