Air bag suspension truth and facts...

[NevadaNick]

Read this one, its about cost saving, not just ride and the ride is only good when loaded. Also freight is packaged better as well as very seldom running empty. All i know is i have owned more than one of both spring types and my air ride coach rides better than my spring ride coaches did. So thats what i will own. http://www.xtralease.com/SiteCollect...20air-ride.pdf

[cbilodeau]

Originally Posted by Scatterbrain

...

Here's a few quotes from them:
This statement (from a company with over 65k trailers on the road) seems to directly contradict Schneider's position paper:

YOU ARE HIDING THE DOCUMENT YOU HAVE USED IN THIS THREAD

In fact you show graph and you talk about XTRA but you did not supply the PDF on which you took this graph.

Why? Do you really want to have a real technical discussion or are you trying to mislead people in their decision.

I have found the PDF from XTRA. They confirm exactly everything the OP has claimed and everthing Scheider study say.

See the PDF that Scatterbrain was hiding from us. Yes we know you read it and did not want us to see their conclusions.

http://www.xtralease.com/SiteCollect...20air-ride.pdf

Here is their PROS and CONS for each suspensions system. For a fully loaded trailer they says that for both spring and air they achieve: "Smooth ride with fully loaded trailer".

Click to enlarge.

What this XTRA document teach me? I can conclude that air suspension will give the driver a better feel if you target the driver himself. Since the tractor is not heavy like a fully loaded truck or motorhome, air for sure will give a better feeling for the driver since we have seen air perform better when not fully loaded (but Scheider say it is 2% better).

A motorhome is not like the tractor pulling a 53' trailer since it is a "one body" vehicule. A motorhome is in my opinion more similar to a trailer. So we must understand the driver in the motorhome is not seating in the front tractor but on the front axle of the fully loaded "trailer".

[cbilodeau]

AIR SUSPENSIONS IS CONSIDERED MORE DANGEROUS BY LARGE TRANSPORTATION COMPANY

BEWARE BEFORE YOU BRING CHILDRENDS IN A USED DP.

According to the XTRA report, air bags should be more dangerous than springs.

The XTRA document is here: http://www.xtralease.com/SiteCollect...20air-ride.pdf

See by yourself what XTRA say, the following text up to the end is from XTRA:


Challenges in operating an air-ride suspension
• Wearable parts have short warranty periods—from one-to-three years. The base suspension structure has a seven-year warranty. Breakdowns in wearable items, such as shock absorbers, air bags and ride height control valves are more likely
to occur.
• Getting parts can be problematic.Not all air bags are the same; bushings are proprietary to the manufacturer.
• While the break-in period is the same as spring ride, inspections need to occur more frequently.
• Often there are not enough inspections of these trailers because they move around so much, so there’s a danger of progressive damage if they are not inspected and maintained properly.
• During the inspection process, a mechanic can’t see a bad bushing. So they just check for loose bolts.
• If a bushing IS bad, a mechanic diagnoses it through symptoms—which typically show up AFTER damage has occurred to the suspension hangers. If other parts have been torn up, you could be looking at a very expensive road call and repair.

Bottom line (this is still in the XTRA report): It’s much more expensive to maintain an air-ride than spring-ride suspension. That’s a lot of money we all could be investing in fuel efficiency.
We know fuel costs have the greatest impact on your bottom line. So to help you cut those costs, we spec low rolling-resistance tires and aerodynamic add-ons. According to EPA testing, that combination leads to about 6.5% in fuel savings.

[cbilodeau]

Originally Posted by NevadaNick

Read this one, its about cost saving, not just ride and the ride is only good when loaded. Also freight is packaged better as well as very seldom running empty. All i know is i have owned more than one of both spring types and my air ride coach rides better than my spring ride coaches did. So thats what i will own. http://www.xtralease.com/SiteCollect...20air-ride.pdf

Like the OP said, most DP with air will have a worst suspension than a spring suspension motorhome. But you should test drive them before buying. Some will perform better than others.

It vary from one builder to another. Spring is better but if you take a bad spring usage vs a not so bad air bags installation for sure the air bag will be better.

I discussed on another thread this week with someone that has same year F53 and same lenght. His ride is completly different from mine since his builder used a an additional axle at the back and he has a long tongue after those two axle and this is where they put the 90 gallons of fresh water. This is unstable since this 90 gallons would be much better located between the front and rear axle.

So we should all listen to what the OP said in his first posts. Spring is better but test drive the motorhome you want to buy and don't trust the selleer if he tells you it is going to be better when loaded because we know now that only spring suspension will perform better when fully loaded. Air suspension will decrease typically the more you load it and the difference with a spring suspension will be as much as 18% according to Scheider.

In fact, it is when not fully loaded when it is brand new that a DP with air suspension will typically perform the better on the road. It is a real catch, they want your money and this work well for them.

[vtwinwilly]

We should be comparing Motorhome leaf/coil spring suspensions to Motorhome air suspensions.

[Gordon Dewald]

"A consultant is a mystical figure who asks you for the number you desire."

My concern is the Schneider study executive summary was written as an infomercial along with information to pick them for moving your goods.

So without the parameters of the study and details of how the study was performed the results are similar to a self proclaimed expert who uses anecdotal information to prove a point. There is some value there but how does it apply.

First there is a lot of comparisons between the suspension on a MH and the suspension on OTR trailers. That is fine if you are hauling people on the trailer. A trailer that is suspended on one end by an air ride (?the tractor).

Common sense says if you inflate your tires to the maximum on the sidewall it will ride rougher than if you weigh your vehicle and inflate the tires to the recommended pressure. So fully inflated all the time = spring suspension, weighing the axle each time and adjusting pressure = air suspension.

But wait! Not a good analogy because springs are manufactured with variable rate characteristics. As the spring bends more leaves come into play and the suspension stiffens up - lighter when lightly loaded and more spring when the load increases. Then the overloads come into play. Manufacturing springs has become a science but I doubt they are able to have a straight progression while air probably is very close.

What is troubling about the studies there is a lack of information on the spring rate characteristics, why those particular loads were selected, the spring configuration and how the loads were placed. Were the light loads placed directly above the trailer axles and the heavier loads distributed? What were the capacity and characteristics of the springs and how much of each load was placed on the sprung axles and how much on the truck? How much did the load vary on the axle? Depending upon the criteria of the study placement of loads could be a factor in the results.

Did the results of loads result in a straight line graph for both suspensions or was it interpolated?

This has been an interesting thread. I now know the professional qualifications of several contributors (interesting but too much information that has nothing to do with the topic) and the opinions of self proclaimed experts who can argue both sides of the question.

Don't forget what works for OTR may not be what you want for a MH. Gas MH rear axles generally are loaded to near the max to get the capacity. Long overhangs ensure the load is moved back to the rear axle. DP have the engine in the rear but normally have extra capacity on the rear while the front is at or near capacity. Both gas and DP MH have issues with side to side loading that is not addressed in the Schneider study.

Perhaps there is a place for springs and air suspension depending upon the application.

Personally it is about what you are happy with. "Your perception is your reality."

[aauummm]

Originally Posted by LVRVLUVR

just got back from picking up my alpine....Smooooooooooooooth

You get the 34' with the 400 hp?

[aauummm]

Originally Posted by vtwinwilly

I just finished reading this entire thread and the whole thing is swirling in my head.

In fact, the only things I know for sure are:

1) LVRVLUVR missed his calling. He should have been a politician. He seems to be able to take multiple positions on the same subject (and amazingly can find someone to argue with no matter which position he takes).

2) cbilodeau is still working on English as a second language. Keep it up buddy, you'll get there!

And...

3) air suspension on a MOTORHOME rides better than leaf or coil springs on a motorhome in most cases! Lookup "Rolling Lobe".

And 4) LVRVLUVR took you all for a ride. He bought an air-bag equipped Alpine yesterday. Pretty high end. He's been wanting to do that for quite a while. I think the air-bag DP folks (and his wife!) gave him his final push to purchase it . Have fun LVRVLUVR!!

[vtwinwilly]

I think this thread ended back on post #168 where LVRVLUVR announced...

Originally Posted by LVRVLUVR

just got back from picking up my alpine....Smooooooooooooooth

...and the Alpine rides on a Neway Air Suspension.

[twinboat]

Originally Posted by NC25T

As I stated earlier where in the keys can you park a coach on the beach? I want to go there!

Nowhere, but you can park near the beach in 2 State Parks.

Bahia Honda and Curry Hammock.

The Fabulous Florida Keys are not known for their long expanses of sand beach. This is not to say there are no Florida Keys sand beaches, just that most are on the small side and often man-made.

Most of the Keys shoreline is mangrove covered coral.

I couldn't resist.

[aauummm]

Originally Posted by vtwinwilly

I think this thread ended back on post #168 where LVRVLUVR announced...




...and the Alpine rides on a Neway Air Suspension.

He'll be back after he takes a video of it pulling a 12K trailer up a 6% grade at 70 mph!

[CampDaven]

Originally Posted by aauummm

He'll be back after he takes a video of it pulling a 12K trailer up a 6% grade at 70 mph!

And after swapping the lousy air suspension with springs.


Dave and Nola, RV Mutants

[Gordon Dewald]

LOL We've been PUNKED! Should know better by now.

[LVRVLUVR]

here's where i'm at the alpine 34'r with the 400 hp...

most powerfull smoothest riding coach I've ever owned.... even better than my 40' freightliner...

I knew if I started the thread those that new would tell the difference...

every one thinks that if they get air bags they're the same ... not so..

a b-b gun will kill a quail.... sure is easier with a 12 ga. though

I also new if I said I was an expert, .. those that new here would tell me what I didn't know

got some very good answers here and I'm now a proud owner of a coach I've been hunting for a long long time..

and yes the hay has been through the horse...but it was only one horse and it was keep in the barn