Spring vs torsion?

[JimGolden]

Everyone,

I recommended the rubber axles to AKTundra for two reasons:
(1) His trailer already came with one and so it'd be easier to replace with like
(2) You do get greater ground clearance, all else being equal, with the rubber one than you do with leaf springs.

That being said, I myself prefer metal springs. They do basically last forever unless abused. And if abused, they're easy to fix. As well, look at the world's automakers....they still use metal springs, be they leaf or coil.

If I were towing on roads all the time, I would prefer leaf springs. But, I assumed that AK would be going over boulders and everything else (from his original post wanting maximum ground clearance to match his truck) and so that's why I went with the rubber torsion axles.

You all want to see a really cool suspension? Check out my two attached pictures here. This is six wheel fully independent suspension with six spring packs, six shock absorbers, and six individually pivoted swing arms. What is this on? This is called "Adjust-a-Ryde" suspension and it is on my '87 Avion 34 footer. Avion has three main frame rails that are 6" deep, and an 8" deep suspension frame that the main coach frame sits on top of. These are heavy duty Dexter axles cut in half and a fitting welded into the end, which are mounted to fittings attached to the center frame rail of the suspension frame. So it's like the old Ford "Twin I-Beam" front suspension. It works great! I run 58psi in my D rated tires and I can lay a plastic spoon on the counter and 500 miles later, it's still there. My pictures on the wall are just on normal hooks and they don't fly off. It really is a good suspension design. But, it doesn't give you maximum ground clearance like a 45 degree down angle torsion axle would. However, I don't pull my 34 footer over 2 foot high boulders. For any kind of decent road, it's excellent. But it's not an off road machine.

The Best way would probably be double wishbones with coil over shocks. But that takes up a lot of room and surely isn't cheap.

For trailers, I like leafs for durability. But if I wanted an off road machine to max out ground clearance, I'd look hard at rubber axles. Although, that being said, the truck has leafs

[Jammer]

Originally Posted by JimGolden

That being said, I myself prefer metal springs. They do basically last forever unless abused. And if abused, they're easy to fix. As well, look at the world's automakers....they still use metal springs, be they leaf or coil.

I almost touched on this in my earlier post but thought I'd wait to see if it came up.

There is very little magic in the fact that the torsion axles used in Airstreams use rubber cords. It's a convenient design because it allows the entire suspension to fit into an axle component that is then merely attached to the frame in two places on each side. The independence, lower unsprung weight, and improved geometry don't depend on rubber.

Automakers generally use independent suspension designs with metal springs. The overall properties of the rear suspension used in most SUVs, typically coil spring or torsion spring designs, are similar to those of the rubber torsion axles used by Airstream. Their disadvantage, in a trailer, is that they place demands on the frame and body that an Airstream cannot accommodate without extensive modifications.

[perryg114]

Too bad they don't make trailer axels with steel rods in them like on the front end of an old VW bug. I don't like that Avion concept with the 6 independent axels and springs. I would think that system would tend to get out of alignment if it is like the control arms on cars.

Perry

[dznf0g]

re. springs.....I replaced 3 out of 4 during the last 4 years I owned my 17 year old SOB. Not overloaded, not abused.....just a LOT of miles. The main leaf broke on each of them at the point of the tip of the second leaf.

Before that, one of the springs on my pop up sagged unequally from the other. Again, always garaged, never overloaded nor abused.

Springs don't last any better than torsion, IMO.

[Aktundra]

I appreciate the input, I guess it's the torsion that I am least familiar with ( as mentioned we come across leaf springs on trucks & such).

I know what a catastrophic failure on a leaf looks like (broken leaf, broken mount, same as previous exept bent, etc). Seems like most the knocks against torsion is they wear out in 20 years ( but what doesn't).

What is catastrophic failure of torsion, look like?

[perryg114]

If the torsion spring fails then it would rest against the stop and you would have no suspension and it would ride real low. I have not heard of any mechanical failures of them like spindles coming off etc.

Perry

[ROBERT CROSS]

When I first started Streaming....

No Forum input...was a real newbie...

63 22' Safari...

Took me way to long to realize that the frequent rivet replacement, erratic towing behavior, vibrations, uneven tire ware, interior appointments finding new locations to reside, broken dishes, difficult wheel removal etc. was because of a worn out axle.
After a ride in the coach trying to find out why the fridge burner kept blowing out, it became apparent immediately that the axel compliance or lack thereof was the cause.

Nothing catastrophic but in total a real PITA.

I guess that's why I'm so anal about the underrated axles on the Classic.

Bob

[dznf0g]

Originally Posted by perryg114

If the torsion spring fails then it would rest against the stop and you would have no suspension and it would ride real low. I have not heard of any mechanical failures of them like spindles coming off etc.

Perry

I've read on here of a few examples...but Andy could tell you better. IIRC, there were some years (a long time ago) when the spindles were too small. Saw a pic somewhere where one broke.

Somebody else had a trailing arm snap off where the square shaft mounts to the trailing arm.

These things seem to me to be more rare than broken leafs, shackles etc on a leaf suspended trailer. Worn shackle pins were always an issue on my leaf suspensions. Even after installing greaseable shackles. (another maintenance item BTW)

[Lothlorian]

My 1960 has leaf spring axels. When I pulled it home everything went really well. I am going to take it to a Mom and Pop trailer shop (they build them, repair them and sell them. I will have them check out the brake system. I wonder what kind of feedback I am going to get? They have been honest and reasonable in price in the past. I hope I don't go ouch when it comes to what they will need.

Brian

[Inland RV Center, In]

Originally Posted by perryg114

If the torsion spring fails then it would rest against the stop and you would have no suspension and it would ride real low. I have not heard of any mechanical failures of them like spindles coming off etc.

Perry

Perry.

Hundreds of torsion axle spindles have failed on old Bambi's and Caravels.

Those axles were under rated to start with and when the rubber rods have exhausted their life, then those spindles will fail because of metal fatigue.

It happens every month. The spindles simply shear off.

Warnings after warnings were posted years ago, about that issue.

Andy

[JimGolden]

I suppose the Avion Adjust-a-Ryde setup could get knocked out of alignment. I have towed mine thousands and thousands of miles and have noticed no abnormal wear patterns on the tires indicating any alignment issues. However, if you did manage to knock it out, there are offset shims in the spring shackles that you could use to change it, similar to the camber adjustment on cars. But, I think you'd have to hit something really hard to knock it out that far. If you did, I'm sure there would be more visible problems than a misalignment

It is a fairly complex system for a trailer, but it works great. They used it for about 10-12 years and only abandoned it in '88 to switch to the rubber torsion axles for their last two years of production. It was a cost savings measure. There was a lot of labor that went into fabricating those axles and then hooking all that stuff up.

AKTundra, if I were you, I would stick with the rubber axles for your particular application. I would either call Andy that just posted on here and have him whip me up one. Or, I would get a Dexter that's rated for 6000lbs on the axle, bearings, etc. Get the big brakes and shock absorber mounts on it. And have them derate the rubber rods so that it's sprung for the weight of your trailer. With all that, you'd be happy trails for probably 15 years.

Best of luck,

[perryg114]

Everything has a finite life. 40-50 yrs is pretty good. I have seen truck axels break as well.

Perry

Originally Posted by Inland RV Center, In

Perry.

Hundreds of torsion axle spindles have failed on old Bambi's and Caravels.

Those axles were under rated to start with and when the rubber rods have exhausted their life, then those spindles will fail because of metal fatigue.

It happens every month. The spindles simply shear off.

Warnings after warnings were posted years ago, about that issue.

Andy

[Action]

Originally Posted by Aktundra

What is catastrophic failure of torsion, look like?

This would be a broken spindle. It isn't pretty and a known issue for the largest single axle trailers in the mid-sixty time frame. Many of those axles have already failed and are either replaced or the trailer was totalled. (Yes that bad)

Otherwise the more common failure in the above mentioned posts at 20 years is the rubber takes a set or hardens up. The best prevention for this is trailer usage. Use the trailer and flew the axle rubber rods and longitivty can be yours. Let it sit in later years and the axle does not allow the wheel assembly to move with the road bumps and the shock of the road bumps is transfered directly to the coach. A result of that is broken rivits and contents that get shook up.

My comment to your original question is don't re-engineer something unless you have big $ and either have an engineering degree or are good with trial and error. If you want a trailer with leaf springs buy one that is designed that way. The engineering for an Airstream with a torsion axle is just that. It was designed for that stress. In the 60's there isn't the design integration that there is now and why change the original design. Just go with the original design. My two cents that are worth less than a penny.

>>>>>>>>>>>>>>Action

[ROBERT CROSS]

In reference to the above post...

If you store for an extended period it will help to unload the axles...

Helps with the tires also.

Bob

[Aktundra]

Ordered the Torsion axel. I guess each one of these is pretty much a custom order, now I wait.

One last question:The local vendor said that nobody had shocks anymore with torsion axels. According to him "they concluded that shocks did not add much to a modern torsion axel"

Should I raise a fuss ?

[vswingfield]

Originally Posted by Aktundra

Ordered the Torsion axel. I guess each one of these is pretty much a custom order, now I wait.

One last question:The local vendor said that nobody had shocks anymore with torsion axels. According to him "they concluded that shocks did not add much to a modern torsion axel"

Should I raise a fuss ?

Take a look at Bob's photo in the previous post. What do you see there?

[Action]

There is a whole different forum about shocks. With differing opinions on your question.

>>>>>>>>>Action

[JimGolden]

I believe they are pretty much self damping when they're newish and the rubber is still resilient. But as they age and the rubber starts to harden up, the damping properties change.

Most trailers I've looked at with the rubber axles do not have shocks.

That being said, I, personally, would want to have them. It's worth a phone call.

You could get mounts welded on locally, you just have to be careful with the heat. You can't get it so hot that you'd melt the rubber chords. It'd be better if the axle maker could put them on for you before they assemble the axle, but if not, it wouldn't be a big deal to do it yourself.

Somebody on here can probably answer this...(it's probably buried in some other thread somewhere...) or just pick up the phone tomorrow and call Airstream and ask them if they're putting shocks on the new ones. If they're not, I probably wouldn't worry about it then.

OK, one last plug: Get your wheels and tires spin balanced! That will probably do as more to save wear and tear as adding shocks to these axles.

[Inland RV Center, In]

Jim.

Welding shock brackets on the torsion arms, using any type welder other than a torch, will not damage the rubber rods.

Henschen added the shock brackets after the axles were assembled.

The large mass of metal on the torsion arm would not allow the heat to travel very far, using a decent welding machine and operator that knows how to weld.

Andy

[ddstech]

I decided to replace the axle, brake componants and springs in my 58

I just got back from the spring shop to have new springs made. Total cost was around 950.00 for two new springs, ubolts, and all the hardware to go along with the springs. He is also going to drill holes and put some sort of spacers in-between each spring for a quieter smoother ride. He claims this is going to be the best way to go. I absolutly was not planning on spending this much, but it is what it is. The bulk of the 950.00 is labor. Also, he made it very clear that the springs you buy in the trailer supply are cheap asian made metal and he is using much thicker metal.

The new axle is only 100.00 and the new brake componants are around 250.00 out the door. I am switching from hydraulic to electric brakes, which is what started this whole replacement.


So yes, I realize its as much and then some as a torsion axle, but for me personally, I prefer to just buy it and bolt it right back into place, rather then have to arrange someone to weld and drill into the frame for the torsion replacement. Also, there is something to be said for keeping some things original on these classics?? I hope..