Why I think axleless suspension is pointless.

[Themontashu]

Alright, so I’m planning my build right now, and have thrown the timbren idea out the window.

Several reasons.

1) cost. Even fabricating my own trailing arms would be more expensive after bushings came springs, shocks, hubs, bla bla (I looked into it)

2) serviceability, you can get regular trailer axle parts anywhere

3) better ride. A rubber bumper will NEVER come close to performing as well as a spring and a shock. There’s a reason cars, motorcycles, mountain bikes, don’t use them.

4) zero practical benefit. Trailer axle tubes are small, and will be well above your differential. You’re not going to be hot with mobility issues cause of the ground clearance of your trailer like that, you’re towing, the mobility is bad.

Now I’m coming at this from some interesting practical experience. I’ve got hundreds (maybe thousands) of off road miles (cross country terrain according to the military) towing 10 different trailers in order to see how they did. All but 1 had a normal axle (or 2 in some cases) and not once did we hit anything. These trailers also had LESS clearence than the tow rig. Additionally, the torsion spring axle was much less controlled in is motion, because as stated, squishing rubber is a bad means of suspension compared to a coil or air spring and an oil damper.


The bottom line is that timbren has convinced you all they solved a problem that doesn’t exist, and to do so sacrificed ride quality, cost, and repairability.

[saywhatthat]

They're more of a sales gimmick go look at your tow vehicle whatever clearance it has that's all the trailer needs. look at all the things that are hanging down on your tow vehicle axle engine pan transmission rear end. At some of the RV repair shops I have invested they've actually figured out a cost to remove some of those. Seems the ones that they have removed the people of got tired of axle alignment and tire replacement
As soon as you have to add a up sales bar to keep them straight there goes more of your ground clearance.
My Pet Rock sold for $3.95, and creator Gary Dahl unloaded more than five million of the igneous invertebrates in six months. He walked away with a cool $15 million. the most successful off road trailers been those little m100 / 416
that is something breaks you get it fixed in hours instead of weeks

[tony.latham]

Additionally, the torsion spring axle was much less controlled in is motion...

What do you mean by that? Less controlled?

Have you ever owned a trailer with a torsion axle? I find that they ride much better than those with springs. No argument over the Axleless axles but in full disclosure, I've never had a trailer with them.



Tony

[Themontashu]

Additionally, the torsion spring axle was much less controlled in is motion...

What do you mean by that? Less controlled?

Have you ever owned a trailer with a torsion axle? I find that they ride much better than those with springs. No argument over the Axleless axles but in full disclosure, I've never had a trailer with them.



Tony

The dampi mg ratio was off with the rubber, to it bounced back and forth. I’ve never owned one, I did a full apples to apples performance and usability evaluation as an engineer. The usability was a few hundred miles of off road driving.

You can screw up a spring and shock axle and make it worse than a torsion or trialing arm (they both squish rubber, the issue is the same in both configurations), but you can always get it way better.

Using rubber as a combination spring damper, like the torsion axles, or the timbren stuff, is worse than a conventional system that’s set up reasonably close to correct. I’m stating this as a matter of fact as well, it can be shown with actual accelerometer data and real world testing.

There are similar things with car suspension too, as far handling and control arm configurations. A double wishbone handles better than a McPherson strut, so long as both are setup correctly.

I’ve actually never pulled a timbren setup, just torsion. I’m just speaking from data I’ve seen with rubber dampers on the timbren, combines with my torsion experience.

[MickinOz]

I once towed a car trailer down South Road in Adelaide, South Australia. It had the cleanest, straightest '69 Mustang body that I have ever seen on it. A zero rust Arizona car. With a brand spanking new Ford Electric Blue paint job. Peak hour, and the owner of the 'stang and supplier of the trailer sitting in the passenger seat. He was so anxious he literally could not tow it himself.
The trailer had tandem Alko rubber torsion axles.
That f'ing trailer was a full 2.5m wide, and was absolutely awful on the skinny two lanes of South Road. It "walked" all over the road. Every tiny little bump was a nightmare.
I towed it all the way to Port Pirie, about 130 miles.
30 years later, I still cringe when people mention rubber suspensions.

Last year I bought a beautiful little power cat. The trailer has bolt on rubber suspension. One side is cactus. I suppose I'll have to replace as a matched set.

At times, I have even considered trying again.
They have a certain elegance about them, interesting geometry for teardrops, possibly a very gentle ride.
I have spent an hour or two with a pencil and my imagination designing the ideal tear drop chassis.

But in the end, NO.
Plenty of Aussies will happily run with swingarms, springs and shocks off-road, but very few have a kind word for rubber torsion arm suspensions.

[aggie79]

My travel trailer has twin torsion axles. Contrary to prior posts, this is the most stable, softest-riding trailer that I ever have towed. Each of the four wheels/tires act independently. When one side experiences a dip, it doesn't transmit shock to the other wheel on the axle, and it doesn't transmit shock to the adjacent axle as happens in a two-axle leaf spring trailer. And, a torsion axle suspension does not aggravate trailer sway as does a solid axle.

Granted, I do not take my travel trailer off-road. But if I were to build an off-road camper, it would not have a solid axle with leaf springs. It would be independent suspension with coil springs and/or air springs.

My 2 cents worth. Take it or leave it.

[Tomterrific]

I like that a torsion axle lets the camper sit lower. That said, a simple leaf spring suspension is dead simple, inexpensive and reliable.

I will say this, every time I hear a trailer doesnt tow straight and goes all over the road I think the operator has it rear weighted. Negative weight on the tongue will have a trailer weaving all over the road.

Tt

[tony.latham]

That said, a simple leaf spring is ... reliable.

They are simple and have been around for over 200 years. But if you Google "broken trailer spring" you get nearly 17 million hits.



Tony

[gudmund]

have owned both - my old teardrop had the Dexter Torsion setup and todays has the leaf spring set-up. My "opinion" sides with the Dexter Torsion" as being the better setup of the two!! The leaf's ride 'just' too stiff and is a very 'high' maintenance setup - to much 'metal to metal' contact points (squeaking all of the time) along with cheap nylon bushed joints with no greaseable zert's - also with shackles/frame mounts that "gull out" - which will need to be replaced some day. (What has helped the ride a bit, was replacing the 'stiff walled' trailer tires with car tires!!) Never had any problem with the Dexter I had had = never any maintenance to be done - just wheel bearing greasing, which both are always in need of......... if and when I ever replace this set-up = the plan is to go with the Dexter set-up again..... What I have written here, is not what I would say is 'fact' = it is just my "opinion" on this subject, for whatever that is worth...............

[timhill28]

My travel trailer has twin torsion axles. Contrary to prior posts, this is the most stable, softest-riding trailer that I ever have towed. Each of the four wheels/tires act independently. When one side experiences a dip, it doesn't transmit shock to the other wheel on the axle, and it doesn't transmit shock to the adjacent axle as happens in a two-axle leaf spring trailer. And, a torsion axle suspension does not aggravate trailer sway as does a solid axle.

Granted, I do not take my travel trailer off-road. But if I were to build an off-road camper, it would not have a solid axle with leaf springs. It would be independent suspension with coil springs and/or air springs.

My 2 cents worth. Take it or leave it.

My friend is looking to get twin torsion axles as well. Good to hear it can make a difference. I'm coming over tomorrow to help him install the suspension from 4Wheelonline onto his truck so he can work on the trailer next.

[tony.latham]

Broken Axleless stub: (Not mine.)



The other side was cracked. The welder said it was the 4th or 5th set of Timbrens he'd fixed.

Tony

[Squigie]

3) better ride. A rubber bumper will NEVER come close to performing as well as a spring and a shock. There’s a reason cars, motorcycles, mountain bikes, don’t use them.

The number of trailers that have shocks is staggeringly low.
Just because the theory is great, doesn't mean you see it in the real world.



And some more thoughts on the various replies above:
Shocks are great, but almost no one adds them to home builds. Even fewer commercial builds have shocks.

Leaf spring trailers bounce like crazy and have minimal suspension travel. "Rubber bumper" style suspension typically smooths things out quite a bit.

Torsion axles tow much, much better, in my opinion, than springs.
However, they are like everything else. They still fail. My current tent trailer is on its 4th torsion axle, which is starting to sag (meaning probable failure in the next 2 years). It is not overloaded. It is not overweight. It is the correct axle for the application. But I'll have a bad day on the highway, sooner than later, when the rubber dies and lets the floor of the trailer drop onto the tire (again). They do fail, just like springs break and Timbrens crack or spit the rubbers out. But the ride and suspension travel are worth it.
I grew up traveling the country in various trailers and motorhomes. I've seen more broken leaf springs than any other type of trailer suspension. Simple and "time-tested" but far from bullet proof and idiot proof.

Trailers that sway and bobble are not loaded or aligned correctly. It is not the suspension type that is the problem, it is the monkey behind the wheel (and/or the cargo loader). And, occasionally, the wrong tow vehicle.

I’ve actually never pulled a timbren setup, just torsion. I’m just speaking from data I’ve seen with rubber dampers on the timbren, combines with my torsion experience.

Care to share this data? Sounds enlightening.

They're more of a sales gimmick go look at your tow vehicle whatever clearance it has that's all the trailer needs. look at all the things that are hanging down on your tow vehicle axle engine pan transmission rear end.

People towing with low vehicles don't need clearance under the trailer.
People towing with trucks and SUVs might. (Might.)
With a leaf-spring solid axle and 12" wheels, most trailers have less than 8" of ground clearance (often less than 6", depending upon spindle offset and spring-over vs spring-under). My truck has 14.5" of clearance to the rear differential and shock mounts - the lowest points. To get that with a leaf-spring solid axle of common design, I would need a trailer tire around 32-34" tall. Torsion and Timbren axles can give you the clearance without giant tires.
I don't want to drag my trailer around off road, with the exceptionally easy ability for an obstacle to totally clear the truck's axle but hang up (hard) on the trailer's solid axle.

[Tom&Shelly]

Just to chime in: We decided on spring suspension, on the advice of our professional trailer fabricator, as springs may be easier to come by and repair, while on the road.

I will say, to my consternation, I've seen air under our tires a few times (while Shelly was driving) including while hitting transitions to bridges on the MA turnpike at 80 mph (or the legal speed limit, whichever is lower, if there is anyone from the turnpike commission reading). Don't know if torsion axles would have helped that or not. Not sure if shocks would help, but we may think about them some day.

We're getting ready to attach an 11 lb propane bomb to our tear, so I'd hate to see it jerk loose during one of those encounters!

Tom

[working on it]

Just to chime in: We decided on spring suspension, on the advice of our professional trailer fabricator, as springs may be easier to come by and repair, while on the road.

I will say, to my consternation, I've seen air under our tires a few times (while Shelly was driving) including while hitting transitions to bridges on the MA turnpike at 80 mph (or the legal speed limit, whichever is lower, if there is anyone from the turnpike commission reading). Don't know if torsion axles would have helped that or not. Not sure if shocks would help, but we may think about them some day.....

* I've commented about a dozen times on why I will always use leaf springs. Number one is "springs may be easier to come by and repair, while on the road"; I've had to replace a couple (one of mine on my old car-hauler, and another on a friend's trailer), and to get one, I only had to drive a few miles to a trailer supply house (8 miles, for mine) and to a Northern Tool (15 miles, for the friend's). I could've also found them at Tractor Supply store, if needed.

* When I replaced my original <1500 lb axle with a 3500 lb Dexter, I opted to get the "standard" 25.25" eye-to-eye springs, instead of the shorter ones that the original had. And, I also chose to get 3000 lb per pair springs, lessening the stiffness, but still overcompensating for an anticipated increase in trailer weight over the years (trailer was 1600 lbs, now at 2225 lbs). I bought the springs at Northern Tool, one near my workplace, and the other near my home (each shop only had one at that rating, but complete sets at other weight ratings).

* I bought the spring hangers and shackles at a Tractor Supply near home, so you can see that parts are available in a lot of places.

* As to "seeing air under the tires", yeah, I've had that happen at least once, with no consequences to the trailer (my 4x8 was at 1800 lbs, then). There was a huge pothole where a bridge transition was, that launched my picup and trailer into the air, breaking steel belts in two of my 10-ply LT truck tires (made the remaining 150-mile drive home a fun experience), but the trailer suffered no damage at all. Perhaps the brand-new LT 27X8.50R14 tires, and the home-made always-active suspension snubbers/bumpstops, that I installed between trailer springs and axle, helped absorb the violent landing. They act much as the Timbren rubber pucks do, but mainly keep the springs under control.

* My opinion on the subject, is to use what you know and trust, and modify it if you choose to make it work better. My choice will remain leaf springs.

[twisted lines]

One Day long ago
Three of us, and it was getting late we just picked up a brand new boat at work.
Under the trailer was one of the rubber axleless with a low offset trailer for a long boat using a long truck,
Nice dinner and a tall beer the driver wasn't me or the boss that was a engineer, dud hit a curb and the boat had no tie down's guess they were extra Bounced (Very) hard.
I like that trailer even after that.

And I have a pair to test very soon; Maken Room.