Front air bags F53

[jharrell]

Originally Posted by ga traveler

Look at the picture of the airbag above. It is between the frame and the spring. As you add air it off loads the spring. Less weight on it. Also the airbag is rubber. It absorbs some of the shock or vibration.


How many f53 chassis have you added airbags? How many f53 chassis have you ridden in before and after adding airbags?

Sorry but this just shows you don't understand how springs works, please look up parallel vs series springs. The two spring share the load in parallel which increases the spring rate. It is now harder to compress the suspension than before, which means firmer, which means more force transmitted to frame over the same bump.

This also means its harder to lean the body due to the stiffer suspension which is why you get less sway.

I don't have to put a bunch of air bags on F53's to understand how airbags work, same with shocks and everything else under the motorhome, its no different than how other straight axle suspension works. I have done airbags on Jeeps and pickups and you put them on to level out the suspension if carrying a heavier than usual load, if you leave pressure in them when loaded normally you get a harsher ride due to the added spring rate, its not rocket science, you are replacing empty open air with compressed air in a bag, which is softer?

[ga traveler]

Originally Posted by jharrell

Sorry but this just shows you don't understand how springs works, please look up parallel vs series springs. The two spring share the load in parallel which increases the spring rate. It is now harder to compress the suspension than before, which means firmer, which means more force transmitted to frame over the same bump.

This also means its harder to lean the body due to the stiffer suspension which is why you get less sway.

I don't have to put a bunch of air bags on F53's to understand how airbags work, same with shocks and everything else under the motorhome, its no different than how other straight axle suspension works. I have done airbags on Jeeps and pickups and you put them on to level out the suspension if carrying a heavier than usual load, if you leave pressure in them when loaded normally you get a harsher ride due to the added spring rate, its not rocket science, you are replacing empty open air with compressed air in a bag, which is softer?

I do not give advice on airbags on Jeep’s and trucks, because I have never installed airbags on either one. I have no idea what will happen. I also don’t think that comparing Jeep’s to motorhomes is quite the same. The weight difference is very different.
When I give my advice it is because I have done a couple of dozen airbag installations on motor homes and EVERY customer was satisfied. I can’t speak for your area, but in Georgia if you talk a redneck into spending $700.00 + on a suspension upgrade it better work or you are sure going to hear about it.

[jharrell]

Originally Posted by ga traveler

I do not give advice on airbags on Jeep’s and trucks, because I have never installed airbags on either one. I have no idea what will happen.

The same that happens on a motorhome, they stiffen up the suspension so you get less sway and are less likely to bottom out, but you get a rougher ride for it.

Physics doesn't change between a Jeep or motorhome, thats why they both have wheels, tires, springs, shocks, sway bars, track bars and everything else. The difference is mainly the weight and COG so the difference in springs is unsurprisingly the spring rate and everything else is the size of the parts. Modern jeeps went to coil springs, older ones had leafs. Rear end on a pickup is basically identical to a F53 except the size of everything, its all works exactly the same. Front end is just like an old pickup, new ones like jeeps have gone control arms and coils doesn't change how it works, springs still spring and adding second springs still makes the suspension stiffer.

You can claim all you want that adding an airbag improves the ride somehow, but it certainly doesn't make the ride softer. I can find plenty of examples of people swearing a sugar pill they paid lots of money for made them feel better, doesn't mean it actually does anything. If it makes the ride better for you its because you like a firmer ride, just trying to make sure people understand what they are changing by adding a helper bag and not fall for a bunch of hocus pocus.

[ga traveler]

Originally Posted by jharrell

The same that happens on a motorhome, they stiffen up the suspension so you get less sway and are less likely to bottom out, but you get a rougher ride for it.

Physics doesn't change between a Jeep or motorhome, thats why they both have wheels, tires, springs, shocks, sway bars, track bars and everything else. The difference is mainly the weight and COG so the difference in springs is unsurprisingly the spring rate and everything else is the size of the parts. Modern jeeps went to coil springs, older ones had leafs. Rear end on a pickup is basically identical to a F53 except the size of everything, its all works exactly the same. Front end is just like an old pickup, new ones like jeeps have gone control arms and coils doesn't change how it works, springs still spring and adding second springs still makes the suspension stiffer.

You can claim all you want that adding an airbag improves the ride somehow, but it certainly doesn't make the ride softer. I can find plenty of examples of people swearing a sugar pill they paid lots of money for made them feel better, doesn't mean it actually does anything. If it makes the ride better for you its because you like a firmer ride, just trying to make sure people understand what they are changing by adding a helper bag and not fall for a bunch of hocus pocus.

It is obvious you and I are not going to agree. I will leave it up to the readers. Believe someone who has NEVER installed airbags on a F 53 chassis. Or believe someone who has installed a couple of dozen and NEVER had a single complaint. I am going by results and you are going by beliefs.
If, as you say, it makes the ride harsher how could everyone be satisfied. Please don’t give me that sugar pill crap. Sugar pills only work on some people not all.

[jharrell]

Originally Posted by ga traveler

It is obvious you and I are not going to agree. I will leave it up to the readers. Believe someone who has NEVER installed airbags on a F 53 chassis. Or believe someone who has installed a couple of dozen and NEVER had a single complaint. I am going by results and you are going by beliefs.
If, as you say, it makes the ride harsher how could everyone be satisfied. Please don’t give me that sugar pill crap. Sugar pills only work on some people not all.

Yes we are at an impasse, on one hand there is the laws of physics and on the other your anecdotes. Psychics have plenty of satisfied customers too, but they can never seem to prove it through scientific means, are you in the supernatural suspension business?

So since I don't have enough experience with F53 air bags to be qualified to explain how they work, how about Kelderman who has done many more F53's than anyone here along with many other vehicles? Here is what they have to say about it:

"How is this different than helper bags? Helper bags are placed directly on the leaf springs or axle in conjunction with the factory leaf springs to help with load support. You won’t see an improvement in ride quality unless you alter the leaf springs in some way. "

https://kelderman.com/specialty/stock-height/

Also here:

"The Kelderman air ride is not to be confused with just adding air bags between the axle and the frame. Air bags are merely helper springs to correct rear sag and to provide additional weight carrying capacity. They do nothing for the ride qualities of the vehicle and in many situations degrades the ride. You lose nothing with Kelderman air ride systems. The main thing you gain with the Kelderman air ride is comfort."

https://www.truckcamperadventure.com...nsion-systems/

Are you disagreeing with Kelderman also even though they have done more F53 air suspensions than yourself?

[ga traveler]

Originally Posted by jharrell

Are you disagreeing with Kelderman also even though they have done more F53 air suspensions than yourself?

Kelderman is great. Much better than just airbags. If someone has big bucks I would recommend Kelderman over airbags. They are much better. However they are in business to sell their product. Do you really believe they are going to praise their competition?

[jharrell]

Originally Posted by ga traveler

Kelderman is great. Much better than just airbags. If someone has big bucks I would recommend Kelderman over airbags. They are much better. However they are in business to sell their product. Do you really believe they are going to praise their competition?

This coming from someone arguing they are right because of the airbags they have sold to customers. It's ok to use your business experience to refute physics, but Kelderman should be ignored because they are selling something even though it agrees with the laws of physics, got it.

Here is a company selling helper bags and even ping tank add-ons:

"Driving without a load while having air springs has a downside to it, and that is the increased spring force which makes empty operation harsh and uncomfortable.

Accumulator tanks help reduce the impulse air springs create. This brings ride quality while unloaded to as close to stock as possible, while allowing you to increase your ability to handle load on demand."

https://pacbrake.com/experiencing-ha...ithout-a-load/

Notice how they say "as close to stock as possible". Pings tanks reduce the progression, they are better than without if you keep pressure in the bags but they are still stiffer than stock. Most people just deflate their bags to minimum psi when they are unloaded to try and turn off the unwanted spring rate.

The springs on a MH are just like a pickup truck unloaded, they are both tuned for the normal travel weight of the vehicle by the manufacturer to be soft and comfortable, part of the reason the F53 has so much sway.

In a pickup if you tow or load the bed up with a lot of weight the springs are too soft and you get lots of sway and maybe even bottoming out, so you get helper air bags to make the suspension stiffer raising ride height back to normal.

Why would you want to do this on a MH unless the springs are too soft to begin with? You don't add helper bags to make the ride softer, you do it to make the ride firmer to reduce sway or prevent bottoming from weak springs. IMO sway bars are a better solution for sway, so whats left is your springs are too soft and you are running below stock ride height and bottoming out, then get air bags or Sumos or whatever.

[ga traveler]

I am sure there are many people who are tired of the bickering, (as am I) so this is my last post on this subject. I only keep going because I am such a fan of airbags and have had such good results with them. I have had customers who were about to get rid of their f53 motorhomes because of the rough ride. It makes you feel good when they come back and are now going to keep them.
To the people who private messaged me with your support, thank you. Just know that I will always be honest in my opinion and like or dislike of any product.
I will always abstain from giving advice on something I personally know nothing about.

[TeJay]

ga traveler,

Two excellent responses to the above posts. This will also be my last post on this aspect of this thread as well. It's obvious there is a disagreement on ideas and results so lets just stop with the bickering and move on.

ga traveler posted, "I only keep going because I am such a fan of airbags and have had such good results with them. I have had customers who were about to get rid of their f53 motorhomes because of the rough ride. It makes you feel good when they come back and are now going to keep them."

I found the lack of any positive comment regarding the above quote from ga very disconcerting. Something is wrong when doing something positive that makes customers happy and nothing good is said. I asked myself why a positive comment was never mentioned. They did a drive down a very rough highway before and after. They were satisfied and happy campers and yet not a single positive remark was to befound in the previous posts.

Those interested in more discussions please send a PM (Private Message). That might stop some of the bickering which is getting us nowhere.

[Nickd]

This thread got a little hot. Not really needed we’re all friends here.
I was educated in the automotive field and worked in suspension and alignment business for about 4 years In the 80’s.

Much respect for Teejay and Jharrell I value their opinions however disagree with both occasionally. We even drive the same Winnebago 18k F53 rigs.

This thread interests me as I have been doing research on improving my Sunstar’s truck like ride.

My opinion so far is Liquid Springs, for the wealthy, Kelderman next best but expensive too. Airbags with ping tanks and on board air third and Sumos are likely an option for some who value simplicity and can’t do air.

Not often discussed is the compromised ride height of a full loaded F53. The spring arc is changed from ideal due to load. Eventually sagging and getting even worse. The spring eve bushings are also crap, have too much play and wear prematurely.

There was a thread a few months back of a F53 owner having his springs reworked and had huge ride improvement. The Escondido CA company added a leaf in the rear and re-arced all the springs to allow proper ride height under full load. The OP said it drove like a different coach after the work.

With respect to Jharrell, there is a lot more going with poor F53 ride quality other than spring rate alone.

Restoring the spring arc to a “lightly weighed” ride height will dramatically change ride quality. The springs also bottom very easily on the F53 causing that knock the cabinets off the walls feeling everyone hates.

However you get there, increasing the arc helps the ride. Softer over small bumps and increased travel before you hit the stops. Think the Koni FSD’s also help the rigs stay off the stops better than the factory Sachs shocks.

Personally I want a Kelderman kit for the front and an extra leaf and re-arc on the rear. If I can’t swing the cost on those, air bags and ping tanks on both axles is a great compromise.

[TeJay]

Nickd,

Many thanks for your comments and different approach to bettering the F-53 ride. I don't know of a place around here to re-arc the springs and for now maybe the cost would be a factor as well. It is however something to consider for sure.

Maybe you have an opinion on the fact that Ford only lists 1 sized shock for front and rear on all f-53 chassis regardless of the weights.

I do understand what a shock does but always thought shocks were deisgned to give a good ride based on the vehicles weight. With only one shock size for all weights what can be done to look at alternative choices except buying all the different sets of shocks and trying them?? As far as I know there's no adjustable shocks avilable.

We do have the Koni's on all corners. I added the 4 Bilsteins that were the original shocks from the factory. WHY?? Just to see how the ride was affected. Yes I understand adding another shock adds more dampening. What if the chassis needed more dampening?? Who's to say it's going to ride better or worse unless it is tried. I didn't spend much $$$$ adding the shocks and I can always take it back to just Koni's or even back to the stock shocks. It's just time on my back under the RV.

Taking a leaf off the back would be an issue because I wouldn't know what to tell the shop what I needed them to do. Asking for further information on that one for sure.

I'd much rather this be at least a partial DIY project. I have somewhat limited equipment but could possible remove both back leaf springs here at home.

Just more to think about.

Again thanks for the different approach to solving this hard riding beast.

TeJay

[MarvinG]

I am one who has added ping tanks to my air bags and do feel a significant difference. If my rig were a lot newer, I might very well spring for Liquid Springs or Kelderman. My chassis is 24 years old! Even if those options were available for a rig this old, it wouldn’t make sense to put that kind of money into it. And they are not available even if it did make sense.

If I had a much, much newer model I probably would go for it. The expense would still be much less than many an expense on a DP I see discussed on this forum.

My Bounder came with airbags installed by the PO. I couldn’t tell a lot of ride difference between them inflated or not. Bumps rattled the cabinets and my teeth alike. Interstate bridge transitions gave me the pucker factor. I also had a lot of porpoising on hitting major dips. Semi’s passing would wag the tail and cause me to correct and then correct back as I was first pushed and then sucked back. SUV’s were even worse than semi’s for some reason. Sway has never been much of a problem.

I first changed the Monroe shocks for Bilsteins. Nothing changed. Still porpoises on heavy road dips. TeJay and I communicated a couple times and after our discussion, I replaced all sway bar bushings, replaced the steering damper, and home-built and installed a rear track bar. Immediately, I can drive with one hand on the steering wheel, relaxed as most any vehicle passes me. The tail wagging is gone.

The porpoising and rough rides remained. On another thread several of us experimented with ping tanks. While I can’t argue with the engineering and mathematical concepts involved, and don’t want to argue about anything really, thus I’ve stayed away from posting this time around, I do want to relate my real-life experience. I’ve done enough testing to be confident my results are not due to the placebo effect.

So, I had the airbags already. I had two, 1-gallon water expansion tanks with air bladders. I thought, all this will cost is the fittings. So the short version is I temporarily mounted the water tanks, plumbed them into front bags and experimented with various pressures and ping tank capacities (as adjusted by the bladders). Since this is already a long post the short version is I could tell a significant improvement with ping tanks aired up to the sweet spot for my chassis. For me, I noticed the improvement on bridge transitions and similar size bumps. Larger bumps are still larger bumps. You can read the entire thread here for a lot of helpful information. https://www.irv2.com/forums/f23/opin...53-475426.html

Recently, I replaced the Bilsteins on the front with Koni’s. For me the Koni’s slightly stiffened the ride back up but at the same time positively reduced the porpoising and improved the way larger bumps are handled.

I don’t think everyone will get the same results. Perhaps some of us with older rigs have weakened springs (though I can’t see any evidence of sag on mine) that allows air bags with ping tanks to improve the ride more than others on newer or different weight rigs. All I know is these updates combined helped mine to the point my wife, sitting in the passenger seat said on our last trip, “You sure have made improvements in the way this thing rides and handles!”

I will continue to read this thread but will not comment further. Feel free to read the thread I linked and PM me if I can help futher.

[Nickd]

Tejay,
Think you are correct that the shock valves in the Koni’s or any of the F53 shocks are just a best guess from an Engineer. They would be triple the price and never in stock if they had to make six valve combinations. The strange thing is how easy it is to get adjustable performance shocks for off road vehicles. Guessing there is no profit to be had from the regular RV owner. If their were, King, Fox, Ohlins, etc. would make us some nice adjustable dampeners.

I bought some High end Gabriel’s for my 2600lb Toad. They fit perfectly, but are WAY too stiff. The shock valves are obviously for a much heavier vehicle.

I would think that’s why there are mixed opinions for the Koni’s. They might be perfect on the 22,000lb F53 but way to stiff for the 16,000 chassis.

I think any good truck spring shop can rework the F53 springs. Those shops however tend to be in bigger cities. I would also want to know the tech had a good understanding of the F53 issues too.

I never thought about adding a leaf to the rear of the F53 until I read that older thread. Guessing the F59’s are almost always light delivery trucks. F53’s are always within a few hundred pounds of being maxed out. When I look at my Winnebago in front of the house, I can tell it sits too low. The springs are in their “heavy load”range in the arc for sure.

[jharrell]

Originally Posted by Nickd

With respect to Jharrell, there is a lot more going with poor F53 ride quality other than spring rate alone.

I am not disagreeing with that, what I am disagreeing with is someone claiming adding airbag makes the suspension softer. Helper springs have their place, and out of all of them I prefer airbags due to their adjustability and being able to do things like add a ping tank.

However there is no escaping the FACT that a helper air spring increases spring rate making the suspension firmer. This may be desirable, but if one doesn't understand that and continues to deny the laws of physics, well I have to call them out on it. They do not magically subtract spring rate from the leafs, and "sharing load" and "absorbing vibration" is nonsense, the stock leafs are still there and do exactly the same thing for every inch of travel as before as they are a constant rate design. Then you add an air bag and for every inch of travel it adds its spring rate to the original leaf. the formula for parallel spring is K = K1 + K2 this is simple addition. Adding more up travel by increasing spring rate does not soften the ride because every inch of compression now takes more force than before. K1 + K2 rather than just K1. To get a softer ride you need a longer spring with lower rate, not a doubled up spring with a higher rate, you must remove spring rate, which is what Kelderman does.

The F53 springs on my chassis are arced properly for the load on them as far as I can tell, they seem to be running at exactly the correct ride height specced from Ford which is to be expected on a newer chassis. My 18k chassis has 550 lbs per inch front leafs. this means at 7000lbs load which is the front axle rating the spring will be at 6 inches of compression and I measure about 6 inches from axle to frame and I am less than the 7000lbs max and measure about 4 inches of droop but the shocks are the ones stopping there not the leafs. This is extremely easy to measure with a tape measure and you can then make your own decisions about need more or less spring rate.

As I have said before if your ride height is too low because of overloaded or old weak springs, then add helper spring to make that up. A new F53 should not need helper springs assuming you're within the chassis GVWR, and they certainly won't make the ride softer. An old F53 that is hitting bump stops due to weak springs, well yes hitting bump stop is harsh, but right up until the bump stops they will be very soft. My bump stops look brand new not sure the last time I hit them and I have been through just about anything you can think of, they certainly don't get much of a workout, again easy to examine. I guess a Gopro pointed at the bump stop would be a good way for someone to actually prove this one way or another, maybe I need to get one.

Everyone seems to be playing with words here, there is a big difference between "poor" vs "better" and "soft vs "firm". One needs to decide whats wrong with their suspension specifically, is the ride too rough? Adding a helper spring and firming up your suspension is not the way to address that because it makes your suspension more firm. Too much sway and bottoming out, yes firm up the suspension.

It is very difficult to both soften your suspension and reduce sway without active (computer like liquid springs or HWH active air) control, if you are improving one it is typically at the expense of the other. This is why all automotive engineers choose sway bars and not air bag helpers, sway bars are a superior design for a helper spring to reduce body roll due to them only engaging on articulation and doing nothing on full axle movement, it is the best non-high tech solution along with digressive shock valving.