Class C rattles teeth when hitting bumps.

Maybe too much air in the bags.

X2

My '99 rides rough in the back unless on a perfectly smooth road. Chassis and bilstein shocks check out ok. In the cab it!s quieter and less of an issue. Guess it's "part of the program".

Adding air may help depending on what the cause of your difficulties are. If you're riding so low that the bumps are causing the suspension to bottom out, then adding air will definitely help. If you're at a proper ride height now, adding air will only stiffen the spring response and probably make the bumps more pronounced and letting air out may be helpful. The airbags do have a minimum pressure that should be maintained, I think usually 10 or 15 psi.

It may be that you have some actual suspension problem, like a broken or binding leaf spring. It may also be that you're expecting rather more than the typical class C suspension can deliver. Going over a decent bump does make the silverware and pots and pans rattle around a good bit. Sometimes the best solution is just to slow down.

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.

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.

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.

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.

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

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!

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!


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