Koni FSD Shocks

pianotuna wrote:
It is a delivery van. It rides rough. I'd love to know how to fix that.

That said, my previous RV was an E-350 and adding a leaf made the ride a lot smoother.

No disrespect intended, but it is a motorhome on a Ford E450 Cutaway chassis. It is not a van. The fact that added leaf springs helped the ride on your previous E350 indicates that there may be ways to improve the pounding and the ride.

It is a delivery van. It rides rough. I'd love to know how to fix that.

That said, my previous RV was an E-350 and adding a leaf made the ride a lot smoother.

Our coach weight on rear axle is 9360 pounds. The axle weight rating is 9450. According to this discussion, the coach should not be pounding as much as a lighter weighted E450. Our coach pounds a lot and is the reason I am thinking about new shocks. I have never ridden in another e450 motorhome, shorter or longer. I do not believe that the pounding could be more than the pounding in our motorhome.

LOG wrote:
Are you saying that an 30 ft rv on a E450 chassis will have a different weight to spring ratio than an 25 ft rv on the E450 chassis? I thought that all E450 chassis in the 2005 year had a rear axle weight rating of 9450 pounds. Are you saying that some E450 chassis have different springs?

The "weight" I'm talking about is the weight of the coach. All E450 chassis of a given year-range have the same coach weight carrying capacity.

When a heavier coach is built onto a given E450 chassis, it's more difficult for the springs to raise the coach up when hitting a small roadway bump. Hence the springs just bend more themselves (than they would with a light weight coach) ... instead of the coach getting thrust upwards as much. This then makes the roadway bump feel less severe inside the coach.

The "ratio" I'm talking about is the weight of the coach versus the weight carrying capacity ("stiffness") of the springs carrying the coach.

pnichols wrote:
Most RVs on the E350/3500 chassis and larger RVs on the E450/4500 chassis - will have a higher vehicle weight to spring stiffness ratio that is not going to transmit sharp jolts from the roadway into the vehicle nearly as much as a lower ratio will. I'm sure Bilsteins (and many other shock brands) will handle these situations well enough.

Are you saying that an 30 ft rv on a E450 chassis will have a different weight to spring ratio than an 25 ft rv on the E450 chassis? I thought that all E450 chassis in the 2005 year had a rear axle weight rating of 9450 pounds. Are you saying that some E450 chassis have different springs?

As I've stated before in these forums - I have absolute proof that the Koni FSD shocks in the rear of our Class C reduced the cracks/pothole pounding back there when traveling: Both our shower door gravity latch back there now stays latched, and the little plastic shelf on the back wall never has it's contents bounce out.

Of course maybe Bilsteins would have done the same - but nothing in the Bilstein literature states that they provide a damping rate that varies depending upon the quickness (frequency) of road surface change.

I really think that where the high frequency light damping mode of the Koni FSD shocks comes into it's own is on RVs that are really stiff springed relative to the motorhome's weight (which is our situation with a 24 foot Class C on the E450 chassis). In these situations a quick bump in the road does not need any shock's resistance added to the spring's resistance - so light or no shock damping is better for reducing the jolt.

Most RVs on the E350/3500 chassis and larger RVs on the E450/4500 chassis - will have a higher vehicle weight to spring stiffness ratio that is not going to transmit sharp jolts from the roadway into the vehicle nearly as much as a lower ratio will. I'm sure Bilsteins (and many other shock brands) will handle these situations well enough.

OFDPOS wrote:
Nope would not do it again . Yes I regret putting them on.
Listened to the popcorn gallery instead of my gut feeling telling me to stay with the Bilstein's !

I have read all of your posts about the FSD shocks and I would not be interested in them at all,I will stick with my Bilsteins!

I was wondering if This offer is still open,who knows you may have a taker :B :B :B

Nope would not do it again . Yes I regret putting them on.
Listened to the popcorn gallery instead of my gut feeling telling me to stay with the Bilstein's !

I recvd some helpful KONI FSD info in the below link.
After just adding a camber kit and the alignment, the ride is so much better.
My next adventure will be adding the Koni's in the rear and the less expensive Bils in the front.


https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29692525.cfm

No regrets; when the time comes I'll probably do it again (or perhaps pay someone to do it again for me in the case of the fronts). I hope I don't have to, though, for some time yet.