Roll and Sway are different. Here's my two cents
ROLL is an angular, movement of the entire rig. That is, it leans
side to side. Roll is controlled by sway bars (correctly called anti sway bars). Sometimes only at the front, but better at both ends. Reducing roll can be done by stiffer sway bar(s) and to a smaller extent by installing stiffer bushings for the sway bar mounting(s).
SWAY is generally when the back of the rig moves laterally
side to side and is generally controlled by a track bar (Panhard bar). Since sway is generally allowed by excessive suspension compliance (slop), I don't think shocks will cure it.
Shock absorbers are also called dampers. That is, they dampen the movement of the suspension. The springs of your motorhome will allow the same eventual amount of roll or compression regardless of what shock is installed, but the rate of roll
will very depending on the shock valving. A stiffer shock will reduce how fast the rig rolls, but it will eventually lean the same amount if you keep on turning since the shock will be compressed. Since a stiffer shock will make the rig roll/ lean slower, it will therefore feel more under control. The downside is that just straight up and down suspension movement from bumps will also be stiffer.
Having said all that, I understand that the FSD Koni shocks allow easier deflection from small movements, like bumps in the road, but act stiffer under larger movements, like turning / cornering / side wind. Maybe some Koni FSD users will add additional information.
Disclaimer: I'm not a suspension expert, but have done considerable suspension development on autocross competition cars (but I didn't sleep in a Holiday Inn Express last night). In the real world the effect of, shocks, springs, track bars anti sway bars and alignment can be complex and it can be difficult to asses the results of one specific change.
Edit: since you reference the CHF (Cheap handling fix) I assume your rig is a Ford chassis with leaf spring rear suspension. Diesel pushers with air bags, etc. are kinda different, and may respond differently to changes.
Originally Posted by al2ride
I figure it's better to start a new thread vs. having to post this on the CHF thread.
I read lots of positive feedback for replacing the stock Bilstein shocks with Koni's FSDs. I ordered a set yesterday and then kept researching and found that some folk notice an increase in sway since the shocks offer a softer ride. Shortly after ordering them and reading the negative feedback, I cancelled the order, but come to find out they arrived today. Not sure how they do it that quickly.
Anyway, I'm no suspension/performance expert by no means and would like to know if a softer shock like the Koni will increase the sway or body roll. I'm assuming that the sway bar is responsible for most of the body roll and that the leaf springs and shocks help a small percentage.
I want to get rid of sway and body roll as much as possible and if the Konis don't help then I don't need them. If they do not decrease the sway or roll, but improve the bumpy ride...then they are worth keeping.