Class C rattles teeth when hitting bumps.

[tmaxx]

I have a 2003 Monaco McKenzie Rogue Class C RV - 29 feet long - 30kmiles. The RV has Firestone air suspension on the back. I got the RV a year ago and have taken several trips. The RV rattles my teeth when I hit potholes on the interstate. It sounds like a bomb going off in the rear of the RV when I hit a bump. I weighed the RV and adjusted the tire pressures. I also put 30psi in the air bags. Neither seems to help. I am at a loss on what to try next. Should I pump up the air bags more?

[klutchdust]

pnichols wrote:
Shot leaf springs probably wouldn't create sharper bump jolts in the rear. Instead, shot rear leaf springs probably would cause a soft "squishy" feeling in the rear ... nice and soft ... but kindof out-of-control handling on curves,in cross winds, and on rounded rolling bumps.

I have a couple of the Koni FSD shocks in the rear. Their effect is subtle, but very real. For example, our Class C's shower is in the rear and has a curtain latch that used to always come out of position from the jolting in the rear. Now it never does. Road potholes and cracks now feel more "rounded off" and not as "sharp". Lateral roll control in side winds and when entering/exiting parking lots also feels more postive and stable. I'll be adding them in the front next year.

On curved winding roads the coach rolls less, it leans and then returns unlike before where it leaned then rolled back then leaned again, a repetitive rocking motion.

As far as the springs, my coach had 19K on it when purchased and basically was like new. Big rigs added shocks to air ride suspensions, they call them shock absorbers for a reason, they

absorb shocks, like a return spring they stabilize the motion so it is not abrupt . Oftentimes you will see a leaf spring configuration where a helper spring comes into play when the load is

real heavy yet the other spring leafs are less rigid to allow for a smoother ride. Rv's are weird, such long hangovers in the back behind the axle, water tanks behind the axle . 40 gallons

hanging off the rear adds 280 pounds plus storage cabinets full of junk etc. I moved all of my heavier items up front . Can't say it will make a difference in your rig but it sure did mine.

[pnichols]

Shot leaf springs probably wouldn't create sharper bump jolts in the rear. Instead, shot rear leaf springs probably would cause a soft "squishy" feeling in the rear ... nice and soft ... but kindof out-of-control handling on curves,in cross winds, and on rounded rolling bumps.

I have a couple of the Koni FSD shocks in the rear. Their effect is subtle, but very real. For example, our Class C's shower is in the rear and has a curtain latch that used to always come out of position from the jolting in the rear. Now it never does. Road potholes and cracks now feel more "rounded off" and not as "sharp". Lateral roll control in side winds and when entering/exiting parking lots also feels more postive and stable. I'll be adding them in the front next year.

[rbreak]

klutchdust wrote:

rbreak wrote:
Same problem here. Tried new monroe rv shocks, firestone airbags (tried 40 and 60 psi so far), and new tires. It might be a little better but still slams hard on the bumps. I'm skeptical on the koni fsd's, for $200 a shock I'd want a money back guarantee that I am going to be thrilled with the improvement. The research I did, some were happy, some weren't that impressed. If the leaf springs are shot, I don't see how a shock is going to fix that. My class C is a 2008 Ford E450 with 22k miles, it's never overloaded and I wouldn't have thought the leaf springs would have completely fatigued yet but maybe they have.

I was very skeptical before dumping $$ into 4 shocks but the results regarding the slamming AND swaying have convinced me. Monroe shocks, in my

opinion, haven't kept up with the new technology out there.I stopped using them on my personal vehicles years ago. Look at the

build of both shocks, the monroe verses the Koni's, there is no comparison. the results speak for themselves. Koni has been building shocks, monroe has

been bought and sold and went overseas. Like sears batteries, they were once the top of the line and now they are junk, they rely on brand loyalty instead

of performance.

I hear what your saying, but I still think if they are going to charge $200 per shock there ought to be a money back guarantee if your not happy. My last truck was a 2007 dodge ram 2500 diesel 4x4 that we used to pull a travel trailer we had before we got the class c we have now. It rode pretty rough which was expected with a 4x4 2500 diesel truck. On some of the forums I used to visit regarding dodge trucks, many people were raving about how the bilstein shocks greatly improved the ride of the truck, that the stock shocks were junk and the bilsteins made the ride so much better. I bought into it and paid a bunch of money for the bilstein shocks, only to find that I couldn't really tell a difference in the ride over the stock shocks that everyone said were junk. I'm a little skeptical now when people say a shock is going to majorly transform the ride of anything. And for $200 a shock, it should be a major transformation.

Plus, back to the original point, if the leaf springs are shot, how is any shock going to fix that?

[klutchdust]

rbreak wrote:
Same problem here. Tried new monroe rv shocks, firestone airbags (tried 40 and 60 psi so far), and new tires. It might be a little better but still slams hard on the bumps. I'm skeptical on the koni fsd's, for $200 a shock I'd want a money back guarantee that I am going to be thrilled with the improvement. The research I did, some were happy, some weren't that impressed. If the leaf springs are shot, I don't see how a shock is going to fix that. My class C is a 2008 Ford E450 with 22k miles, it's never overloaded and I wouldn't have thought the leaf springs would have completely fatigued yet but maybe they have.

I was very skeptical before dumping $$ into 4 shocks but the results regarding the slamming AND swaying have convinced me. Monroe shocks, in my

opinion, haven't kept up with the new technology out there.I stopped using them on my personal vehicles years ago. Look at the

build of both shocks, the monroe verses the Koni's, there is no comparison. the results speak for themselves. Koni has been building shocks, monroe has

been bought and sold and went overseas. Like sears batteries, they were once the top of the line and now they are junk, they rely on brand loyalty instead

of performance.

[rbreak]

Same problem here. Tried new monroe rv shocks, firestone airbags (tried 40 and 60 psi so far), and new tires. It might be a little better but still slams hard on the bumps. I'm skeptical on the koni fsd's, for $200 a shock I'd want a money back guarantee that I am going to be thrilled with the improvement. The research I did, some were happy, some weren't that impressed. If the leaf springs are shot, I don't see how a shock is going to fix that. My class C is a 2008 Ford E450 with 22k miles, it's never overloaded and I wouldn't have thought the leaf springs would have completely fatigued yet but maybe they have.

[klutchdust]

I had same problem installed Koni shocks and 40 psi in air bags, problem now minimal.

[Healeyman]

tmaxx wrote:
When I get back home in a week, I will try adding more air to the air bags and report back.

Great. I'd love to hear.

Remember, while adding air, if the back end doesn't rise up, the bags are not carrying any of the load. Mine rose 1 1/2 - 2 inches.

Tim

[wearenh]

Healeyman wrote:
...

I respectfully disagree with the other posters that you have too much air in the bags. I think that you don't have near enough.

I suggest that you add 50-60 PSI and take it for a ride and see if that makes a difference. Adjust the air pressure as needed. As you add air, watch to see if the house rises. If the rear doesn't rise, the bags aren't lifting to help carry the load...

+1 ... we normally run 70psi, and 90psi when towing

pnichols wrote:


I installed Koni FSD shocks in the rear and they do reduce the sharp jolts in the rear from potholes and highway cracks. I have absolute proof of it ...These particular Koni shocks are not just "another expensive shock". They're based on a different technology than other popular non-stock Class C shocks - such as Bilstein or Monroe shocks .... which is the reason that the Koni FSD's can perform the way that they do....Here's a link explaining what they are:

http://www.shockwarehouse.com/news/koni-fsd-gold.cfm

+1 on these too ... with the bags at full pressure and the Koni FSD the ride is TRANSFORMED!


.

[tmaxx]

I am on vacation in NY right now. When I get back home in a week, I will try adding more air to the air bags and report back.
Thanks!

[pnichols]

I installed Koni FSD shocks in the rear and they do reduce the sharp jolts in the rear from potholes and highway cracks. I have absolute proof of it in that the shower door latch (the shower is way back against the back wall) no longer ever shakes out of position as we travel.

We have just about the worst case Class C stiffness setup too - a 24 foot Class C on the Ford E450 chassis. These particular Koni shocks are not just "another expensive shock". They're based on a different technology than other popular non-stock Class C shocks - such as Bilstein or Monroe shocks .... which is the reason that the Koni FSD's can perform the way that they do.

You might want to give them a try. Start with just a couple in the rear and leave what you have in the front for awhile.

Here's a link explaining what they are:

http://www.shockwarehouse.com/news/koni-fsd-gold.cfm

[Bordercollie]

Most concrete interstates are cupped from heavy trucks and weather wear. Take frequent breaks at rest stops to relax from pounding. Asphalt secondary roads are usually more scenic and sometimes smoother.

[Jbrowland]

My RV rattles uphill both ways and I like it. 😉 I suggest buying a boat if you don't like the rattle of an almost 30 foot class C. 🙂 Sure, you may have a serious issue but barring that, you may just be another class C owner. I have been in class C's with suspension "improvements" and for the money spent, the improvement was nebligible but that's just MHO. Perhaps for full timers who drive a lot the mods may be worth it.

[Healeyman]

Our first RV was a 22 footer on a Chevy 2500 chassis. Even though it was only 3 years old with 30,000 miles when we got it, the rear spring stack was absolutely FLAT with NO arch, hence, there was NO springiness to absorb the upward movement of the axle on a bump or coming out of a pot hole.

Without rear springiness, the rear axle had to lift the whole back end. The rear ride was so rough that it actually broke glassware in the cabinet.

After a few months of tolerating it, I installed a set of rear Air-Lift air bags. The same bags as your Firestones.

As I added 50 PSI of air pressure, I watched as the air bag lifted the "house" 1-1/2 inches.

After adding 50 PSI to each bag, and letting the bags actually help the springs, it was a TOTALLY different ride.

I respectfully disagree with the other posters that you have too much air in the bags. I think that you don't have near enough.

I suggest that you add 50-60 PSI and take it for a ride and see if that makes a difference. Adjust the air pressure as needed. As you add air, watch to see if the house rises. If the rear doesn't rise, the bags aren't lifting to help carry the load.

I have Firestones on my current 30' Class C, but I have never had to air them up.

Tim

PS: Please let us know what happens.

[rockhillmanor]

Leaf springs. Metal fatigues period. Mine was slam banging over the road too. It was the leaf springs. I put new ones on PLUS one extra leaf. Ahhhh.

I'd go to a frame shop or a repair shop that knows about suspension. They have a whole mathematical thing going on with suspension. They even asked me how much lift I wanted in the rear end!

When all was said and done the ride was unbelievable and it DID lift the back end up. Actually it probably put it back where it was when new and had new leaf springs. :W All I know is I don't bottom out anymore going up those nasty gas station driveways.

sometimes you can just add a leaf spring to help the old tired ones. IMHO I consider air bags is just a band-aide on bad leaf springs and air bags just give a hard ride which is not what we want in an RV. Just saying.