Which shocks IF...

Heavy duty shocks are nice but if your shocks are toast, honestly any new shock is better than what you currently have. I put on normal replacement shocks a couple years back and am very pleased with their performance!
Brian

Bordercollie wrote:
What would be the best way to improve harsh ride from rear duals on cupped concrete highways. ( Change rear springs, add airbags or ??) We get out and walk around at rest stops. Tioga 26Q 80 psi in rear tires, 75 in fronts.

A few years ago I had my OEM rear shocks replaced with Koni FSD shocks to see if their dual zone damping would help with the cracks and potholes pounding in the rear.

The FSD shocks did the trick. As an indicator - our shower door latch (our shower is in the rear) would always come loose from the jolts which the OEM shocks would not reduce. The latch has never come loose in the years since installation of the FSD shocks back there.

In fact I think that the relatively always-stiff OEM shocks were adding to the stiffness of my under-loaded rear leaf springs at all times and in all situations. Now the FSD shocks only "auto-adjust to stiff" with the slower happening swaying forces from curves, side winds, from parking lot curbs, and from passing box trucks.

The above are examples of the dual action affects from these shocks - stiff when slow acting damping is required, and soft when quick acting damping is required.

I run 75-80 lbs. pressure in the rear duals and 65-70 lbs. pressure in the front singles. Our 24 foot Class C runs around 12,000 lbs. when fully loaded on it's E450 chassis.

What would be the best way to improve harsh ride from rear duals on cupped concrete highways. ( Change rear springs, add airbags or ??) We get out and walk around at rest stops. Tioga 26Q 80 psi in rear tires, 75 in fronts.

DrewE wrote:

pnichols wrote:
Ron, of course if your heavy duty front shocks also mean that they're stiffer shocks - then your front ride could be rougher than necessary for two reasons -> under loaded front coil springs plus shocks that don't compress/extend as easily.

Do you have rear air bags that you can adjust to permanently raise the rear and hence transfer more weight unto the front?

Raising the rear does not transfer any significant amount of weight to the front, any more than parking on a slight hill does. Probably a pet walking from the rear to the front of the motor home causes about as much weight transfer.

I guess if you raise the rear by several feet things would start to be a little different....

I believe the most influential factor is that our E350 is 23'-8" long with a 158" wheelbase resulting in a significant rear overhang. Then adding that our fresh water tank is against the rear wall (and we always carry a full tank), the teeter-totter effect lifts & lightens the front axle.

Regarding the heavy duty Bilstein shocks I recently installed, they are the right choice for our rig today. I don't feel they would be a problem with the next lower coil spring rate. When the teeter goes totter, they should do well in cancelling it regardless of the spring rate.

pnichols wrote:
Ron, of course if your heavy duty front shocks also mean that they're stiffer shocks - then your front ride could be rougher than necessary for two reasons -> underloaded front coil springs plus shocks that don't compress/extend as easily.

Do you have rear air bags that you can adjust to permanently raise the rear and hence transfer more weight unto the front?

Raising the rear does not transfer any significant amount of weight to the front, any more than parking on a slight hill does. Probably a pet walking from the rear to the front of the motorhome causes about as much weight transfer.

I guess if you raise the rear by several feet things would start to be a little different....

Ron, of course if your heavy duty front shocks also mean that they're stiffer shocks - then your front ride could be rougher than necessary for two reasons -> underloaded front coil springs plus shocks that don't compress/extend as easily.

Do you have rear air bags that you can adjust to permanently raise the rear and hence transfer more weight unto the front?

FunTwoDrv wrote:
Ron,
That cupping on your right tire looked very much like the tires on our C. Unfortunately this happened after we put new shocks on. The tire mfg said it was due to us not rotating the tires. However, Michelin dealer claimed it was due to an out-of-balance issue caused by a belt failure... who knows! I put a new set of Michelins on and are watching them closely so as to not revisit this same issue down the road.
Gary

Hi Gary,

I was at an automotive workshop where "cupping" like I have was discussed. The person giving the lecture said "cupping" is caused from an improper alignment.

I do wonder if our lighter-weighted front wheel alignment which was compensated through off-set bushings, would have been better addressed through replacing the front coil springs with E150 springs.

The front coil springs on my E350 Super Duty chassis handle 4600 pounds.
My on-trip loaded rig with us in the front two seats, the entire front end weighs only 3260 pounds.
The E150 coil springs handle 3900 pounds, still too much, but closer to the actual load.

Because my front coil springs are rated so much more than my actual load, my front end sits higher than it should. The offset bushings installed addressed the positive camber created from the condition, but I feel the better solution are lower-rated front springs. Not just for alignment purposes, but also to provide a more comfortable ride. The heavy duty shocks should keep the front end under proper control to prevent any extra porpoising.

Ron Dittmer
2007 Phoenix Cruiser motor home built on a Ford E350-V10 Super Duty chassis with OEM 158" wheel base

Ron,
That cupping on your right tire looked very much like the tires on our C. Unfortunately this happened after we put new shocks on. The tire mfg said it was due to us not rotating the tires. However, Michelin dealer claimed it was due to an out-of-balance issue caused by a belt failure... who knows! I put a new set of Michelins on and are watching them closely so as to not revisit this same issue down the road.
Gary

CLICK HERE to read my story with many pictures on shocks. My solution was going with heavy duty Bilstein shocks from Tire Rack, and installed them myself to make it an affordable project.

BTW, my front tires also had "cupping" damage. If you look close, you can see it in the first picture in my CLICK HERE. I assume the damage occurred from the original bad front shocks.

FunTwoDrv wrote:
Although we went with Bilstien shocks, my thinking is to go with the best shock you can afford. Our Chevy 4500 chassis had two completely worn out shocks at 17K miles... one front & one rear!

Lumpty wrote:
I had Bilsteins on the front of my E450, and found the digressive valving too floaty as I'm lightly loaded with a no-slide 24' house. The front tires were cupping badly. Switched to a pair of Monroe Magnum RV shocks, which were all of something like $25/each using an Advance Auto coupon, and they resulted in a much more controlled ride, and also the tires are wearing evenly as the twin I-beam front end isn't going up and down all the time with it's inherent toe change.

Lumpy, could you elaborate on the "cupping" you experienced? Our current tires are starting to show cupping in the center of the tread. Scheduled Friday to replace all six with Michelin.

Gary

This was consistent across all the Michelin LTX tread blocks on both front tires. Another term for it is feathering. Below is a picture found elsewhere on the internet of that same tire on a Ford Econoline starting to do the same thing: