Can't resist jumping in on this one. We just drove from the Oregon border, down 101 to the Bay Area. AWFUL roads much of the way. Then down I-5, over the Grapevine, on through to South of LA. More TERRIBLE roads. Then back to Oregon I-5 all the way - - The freeway is somewhat better from Sacramento to Oregon, but still no treat.
However, all of this is made incredibly worse by the skate-board suspension on our 2001 Coach House (23 ft) on an E450 chassis. Having already put some miles on this rig, I knew it wasn't a great ride, but had no idea it would be this bad. Prior to the trip, we carefully weighed all four corners, and appropriately adjusted the tire pressure on a new set of Michelins. The recommended pressures were quite low I thought - - 50 in front, 65 in the duals. This left me with a small safety margin, but at every stop I check the temps with an infrared gauge - - we were OK everytime, even in 100 degree weather. We are carrying a full water tank, and an average load of goodies, but still have about 1000 lbs. of CC in reserve. Must say that handling is fine - - no complaints there. Also enjoying the really good brakes - - (compared to my last 7 motorhomes). Like the ease of driving something smaller too.
Anyhow, we are considering both Koni shocks and MorRyde. Henderson's wants about 1900 bucks for the MorRyde installed - - probably end up doing my own. They told me they could put a full airbag (rear) suspension on that was really a huge improvement - - but about 5000 bucks and totally replaces the leaf springs.
I spent a lot of time, effort and money making my diesel pusher ride and handle well. I think it was a great investment though. Now that we've downsized, we'll try it again on the E450. The present ride is waaaay too harsh.
The reason for spelling is so that all of the words don't look the same.
If the E450 is equipped with the Firestone Ride Rite air bags, check that the upper and lower brackets are not colliding.
This is a fairly common problem.
The Ford rear springs are not arched when new.
cptnhook wrote: Rv.net folks: Really enjoy this board and am hoping to solve a stiff suspension issue in our 07 Jamboree 25Q. Special thanks for tips on tire pressure, front end alignment and weighing the MH for correct tire pressure. These measures have solved
40% of the problem, however the coach still feels every bump and expansion joint on our CA freeway system. She weighs 12020 lbs w/ full water and gas, 3900 front, 8120 rear and sits on a Ford E450 frame, so simple math says that we a heavy duty foundation for our relatively small house on wheels! My alignment shop is recommending Koni shocks as a solution and has also suggested that I have the rear leaf springs rebuilt to provide more flex at the rear axle.
I’ve read rave reviews on the Koni’s but have no idea what problems or warranty issues we might run into rebuilding the E450 leaf springs? ANY ideas or expertise on springs
and shocks would be sincerely appreciated.
Dave S
Some generic ride/handling comments...
Stiff springs need STIFFER SHOCKS than soft springs. The reason being, is that the stiff springs have what is known as a "high rate" oscillation. In other words, they deliver a higher frequency shock to the chassis over bumps, etc. Normal shocks simply haven't the resistance to stop the axle from this rapid oscillating type motion - and what you feel is like this... Drive over a broom handle, and it feels like you hit a curb. Not because the rig moves up and down, but because the axle and springs oscillated several times while jumping over the little obstruction, and the whole vehicle transmit a harsh "Bang" to the seat of your pants and hands and ears. What you felt was the tires hitting the obstruction, the rig bouncing upward, then the axle dropping downward and yanking the rig back toward it, just to "bounce" on the tire and transmit a second, harmonic motion to the chassis. Proper rate and stiffness shocks will dampen the harmonics and rebound shocks.
Now, firmer shocks will make the ride more... solid. In other words, you hit uneven pavement and the chassis follows it, feeling a bit tossed around. However, in a corner, hitting a big wallow turns into an uncomfortable bump, but there's no wallowing or swerving around trying to get it back into the right arc through the corner.
Yes, firmer shocks seem to help both soft and harder springs, but it demands more of, wears out faster, and stresses harder, the shocks which try to dampen the oscillations springs naturally vibrate at.
Thus, if you have a very stiffly sprung vehicle, it calls for very firm shocks, but at the same time, wears them out quickly, because the springs are always attempting to move the shocks in or out at a high rate of speed.
++++++++++++++++++++++++++++++++++++++++++
Mopars forever... Not German, Japanese, Chinese...American Mopars!
The price of freedom is higher than the price of slavery, but it's still a bargain!
Reading all of the above comments regarding shocks really makes my point from my earlier post:
What is probably best is adjustable shocks for the E450, that a mortal can afford, so we can tune our individual rigs' rear ride just right with a little experimentation.
Why in the world doesn't Rancho offer 9000's for the E450??? ... or isn't whoever made the Rancho 9000 in business anymore?
65CrewCabPW wrote: Some generic ride/handling comments...
Stiff springs need STIFFER SHOCKS than soft springs. The reason being, is that the stiff springs have what is known as a "high rate" oscillation. In other words, they deliver a higher frequency shock to the chassis over bumps, etc. Normal shocks simply haven't the resistance to stop the axle from this rapid oscillating type motion - and what you feel is like this... Drive over a broom handle, and it feels like you hit a curb. Not because the rig moves up and down, but because the axle and springs oscillated several times while jumping over the little obstruction, and the whole vehicle transmit a harsh "Bang" to the seat of your pants and hands and ears. What you felt was the tires hitting the obstruction, the rig bouncing upward, then the axle dropping downward and yanking the rig back toward it, just to "bounce" on the tire and transmit a second, harmonic motion to the chassis. Proper rate and stiffness shocks will dampen the harmonics and rebound shocks.
Now, firmer shocks will make the ride more... solid. In other words, you hit uneven pavement and the chassis follows it, feeling a bit tossed around. However, in a corner, hitting a big wallow turns into an uncomfortable bump, but there's no wallowing or swerving around trying to get it back into the right arc through the corner.
Yes, firmer shocks seem to help both soft and harder springs, but it demands more of, wears out faster, and stresses harder, the shocks which try to dampen the oscillations springs naturally vibrate at.
Thus, if you have a very stiffly sprung vehicle, it calls for very firm shocks, but at the same time, wears them out quickly, because the springs are always attempting to move the shocks in or out at a high rate of speed.
Excellent dissertation on how a shock should function. There is another facet which needs to also be considered, but may not be as important a factor on the E450 chassis. The smoothness of a ride is affected by the ratio of the unsprung versus sprung weight. In other words, the total weight above the springs and total weight below the springs. Taking some extreme examples - suppose a vehicle weighing 11,000 lbs had 1,000 lbs above the springs and 10,000 lbs under the springs. Those 10,000 lbs could easily jar the passenger sitting on the 1,000 lbs. Or the other extreme where 1,000 lbs under the springs tried to jostle the 10,000 lbs above the springs. One of the contributing factors is the capacity of the spring required to support the unsprung weight. The shock must compress softly to allow the unsprung weight to rise up over the broom handle, but yet must remain firm to not allow the unsprung weight to bounce. Shock design is more complex than it appears.
What did you figure out about your rough ridin' Class C. What was the problem ?
Have you fixed it yet ?
Tim
Hi Tim:
Did spring for a set of Koni reds and set them for softest ride.
They made a small difference but not enough to justify cost.
Next step was to fill all holding tanks to capacity and load 1200 lbs
of Redi-Crete over the rear axle. This DID help smooth the ride on
freeway expansion joints. I think it will take rebuilding the leaf springs or going to the MOR-ryde system to really solve the problem.
Dave
To those of you who have a rough ride in the back of your Class C and/or are using adjusted tire pressure and/or increased vehicle mass to moderate your ride, I urge you to go back and re-read my post of 6/19/08.
I am a retired engineer and have designed and fabricated suspension systems for several of the
not-a-kit custom cars that I have built. I am absolutely NOT and don’t pretend to be the expert here, but I DID have the same problem and I DID solve it.
If pavement disruptions as slight as the expansion joints in the Interstate jar your teeth and everything else in the back, I strongly suspect that you have little or no spring travel.
If that is the case, the best shocks in the world will do nothing to improve your ride. Shock absorbers, especially gas charged, are primarily designed to attenuate rapid axle travel while the axle is traveling UPWARDS over a bump. This action delivers a softer upwards force to the chassis and body.
If your rear springs are “coil bound”, as mine were, the shock absorber is then only working as the smaller axle mass falls (after the bump), before the larger mass of the body and chassis and only works to slow the fall of the chassis and body.
I re-urge you to inspect your ACTUAL upwards spring and axle travel. You cannot just look at the distance between the axle and the rubber bump stop. Even though my springs were metal to metal (coil bound) with NO travel, there was over 2 inches of space between the axle and the bump stop. The bump stop had NEVER been touched.
I have no idea what my vehicle weight was. That didn’t matter… The springs had NO upwards travel and the springs and shocks were not working.
As you will read in my previous post, I SOLVED my problem with relatively inexpensive Air-Lift air bags as opposed to re-building/re-arching the springs. I now have 1 1/2 “ of spring travel and now hear absolutely no noises from the back.
If you do inspect your rear suspension, please let us know what you find. I may be full of stuffing and maybe my situation was unique and air bags will not work anyone else.
Thanks for reading,
Tim
* This post was
edited 07/08/08 11:32am by Healeyman *
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