Swing arm suspension?

[Teardropper]

For instance: Full load, 22.5º down and I'm seeing 1.49 to 2.31" of outer radius arm travel. They're just not a performance suspension system. They're cheap and simple

You're reading the wrong column. Dexter says you need 3" of fender clearance after the trailer is loaded. (I've had to raise my fender clearance because of that issue.)

All new military utility trailers are equipped with 3500# Dexter Torflex axles.

T

 

[spressomon]

This from the Boler site regarding Dexter Torflex axle system:

Replacing your Axle
Over time the axle will wear out, the rubber elastomer will deteriorate with use and age. As the elastomer deteriorates the axle will start to sag, causing the trailer to sit lower, there can also be movement laterally in the torsion tube which will cause the wheels to toe out, this can cause slight swaying and tire wear. The most noticeable result will be a harsh ride, often noticed by seat cushions flying everywhere, cupboard doors open and even bouncing of the trailer even when the road appears smooth. As a general rule of thumb an axle that is 15-20 years old probably needs replacing.

The bold type above describes our now 6-year old Escape 15A (1600lbs dry) to a tee. I purchased it a year ago from the original owners who seldom used the trailer with an estimated 5000 miles on it then with most of those miles coming from towing it from Escape Industries in BC Canada to south Texas when they purchased it new. Towed it back from south Texas to Carson City and given the displaced cabinet doors and cushions I would say, even on paved highway, it was akin to little to no suspension.

Just my opinion, but after selling to the federal government for a decade or more, I wouldn't purchase a product just because the military bought it; or any other faction of our government.

 

[Teardropper]

site regarding Dexter Torflex axle system

You and I are going to continue to disagree on torsion axles. My like for them is based on twenty-five years of usage without any issues.

Tony

 

[spressomon]

You and I are going to continue to disagree on torsion axles. My like for them is based on twenty-five years of usage without any issues.
Tony

After experiencing what seems like suspension bottom out bobbing apart of a little trip last week I had the trailer weighed on a CAT scale: 2560lbs (with tow rig connected but on separate pad; so need to add back approximately 250-300lbs to account for tongue weight); below the 3500lb #10 Torflex rating per the OEM build sheet for same provided by Dexter yesterday (incredible customer service experience with Dexter yesterday BTW!).

The arms when new were 22.5º down and now sit horizontal and given how the trailer bobs it seems there is failure apart of the torsion system. But the big question is: Why!
Just 1-year out of warranty too, darn it.

In process of ordering same and we'll see how it goes...but mysterious why it failed so young and well below weight rating.

 

[high-and-dry]

After experiencing what seems like suspension bottom out bobbing apart of a little trip last week I had the trailer weighed on a CAT scale: 2560lbs (with tow rig connected but on separate pad; so need to add back approximately 250-300lbs to account for tongue weight); below the 3500lb #10 Torflex rating per the OEM build sheet for same provided by Dexter yesterday (incredible customer service experience with Dexter yesterday BTW!).

The arms when new were 22.5º down and now sit horizontal and given how the trailer bobs it seems there is failure apart of the torsion system. But the big question is: Why!
Just 1-year out of warranty too, darn it.

In process of ordering same and we'll see how it goes...but mysterious why it failed so young and well below weight rating.

Not defending dexter, but I am waiting for my axle to to be made by them.

Couple of questions, was the 22.5 down unloaded or loaded? if unloaded then that would not surprise me for it to be roughly in the middle of its range of motion when loaded.
I have always heard design for a max of 80% of the axle rating for total trailer weight, well your over that. Which means your not well below the rating.
Was the trailer ever well over loaded, or do you use stabilizers when parked. 2 or 3 people in the trailer can easily add up to enough weight to be at the axle rating. Also was the weigh in with tanks empty or dry, that could add 200 lb for a 25 gallon tank.
What was the axle rated at when new , as they can be down rated.

Lastly and I think this could be a design flaw for the independent suspension of the torflex design. was the trailer ever parked on a pretty decent slope to one side or another for any time? I mean if you parked it sideways on a 5 to 10 degree slope, I could see that shifting a bunch of weight to one side of the axle. This could make one side of the axle easily have to support 2000 lbs instead of 1300. This is where I think a sway bar setup up would be good.

My axle is/will a torflex when ever dexter makes it and ships it. I used the 3500lb axle rated at 2k, my trailer weight I want to be around 1500 dry.

 

[spressomon]

^ Per Connie Massie, Warranty & Service Administrator at Dexter Corp: She recommends the 3500# rated Torflex; said the rating is conservative and could handle 300lbs more (3800lbs) without issue. She seemed very knowledgable and discouraged me from ordering heavier rated axle. She said over-rated axle system capacity would have the same negative suspension traits as too light.

Rolling down the road, fully loaded fridge, 25-gallons water, etc., does not exceed 3000lbs. Haven't entered the Baja 1000 with it yet.

She said over time the Torflex will lose 10º; didn't ask her why but assume the rubber rods fatigue somewhat over time. When I told her the arms on my Torflex, at 2800lbs or so, are perfectly horizontal, she said something is wrong as they should be ~ 10-15º down given 6-years old and the gross weight under their rated capacity of 3500lbs.

We purchased the trailer from the original owner and have no idea how much weight they carried. I do remember when we towed it back from Texas all cushions, cabinet doors and drawers opened from the rough ride.

This is my first experience with Torflex. The fanboy camp seems to be divided into those that swear by it and those that swear at it. I'm still undecided whether to spend $500 +/- on a new Torflex or put that toward a well designed leaf spring & good shock set-up.

 

[high-and-dry]

I was torn on going to the timbern but if my trailer sees 2 k a year I would be surprised.

Oh and the reason you dont see many home built swing arms, is it takes lots of skill to make it work right, getting the alignment correct etc. Also a spring or torsion axle only needs frame rails to attached to, where a swing arm needs a strong mount in two places, one where it pivots and another for the spring perch on top.

 

[high-and-dry]

I'm still undecided whether to spend $500 +/- on a new Torflex or put that toward a well designed leaf spring & good shock set-up.

If I was going spring axle I would not use trailer springs, I would look for one much longer, so it has more flex, less bounce.

 

[spressomon]

If I was going spring axle I would not use trailer springs, I would look for one much longer, so it has more flex, less bounce.

Exactly. Nothing will be used from the RV industry LOL. Probably 60-Series length springs and good shocks as they worked really well on another custom trailer I had. I just don't have time to do all that right now...OTOH waiting 2-3 months for a new Torflex kinda screws us for upcoming trips.

 

[Peter_n_Margaret]

If I was going spring axle I would not use trailer springs, I would look for one much longer, so it has more flex, less bounce.

Yep. But dampers are absolutely essential.
I see absolutely no value in independent suspension on a trailer. It is a fashion. It offers no performance benefit, but lots of potential hassles.
Cheers,
Peter
OKA196 motorhome

 

[gatorgrizz27]

Yep. But dampers are absolutely essential.
I see absolutely no value in independent suspension on a trailer. It is a fashion. It offers no performance benefit, but lots of potential hassles.
Cheers,
Peter
OKA196 motorhome

I tend to agree when it comes to the actual suspension part. The two benefits I see are increased clearance in the center (not getting hung up on an axle tube), and being able to minimize the trailer width by needing less clearance from the inside of the tire to the frame.

 

[billiebob]

Independent vs Solid Axle.

The big advantage should be reduced unsprung weight with independent suspensions. The advantage of a solid axle is simplicity and durability. Either do the job well but leafs springs and a solid axle are much less expensive and pretty much maintenance free. One of my trailers has 100K miles on it and is on its 3rd set of tires but I've never touched the suspension or bearings. Not sure I'd get that kind of performance from any of the independent setups.

 

[old_CWO]

CJ7 rear suspension for Jeep with M20 axle. The u-bolt plates have shock pins, and the M20 u-bolts will fit the 3.5K trailer axle. The springs are short enough to fit a six foot long trailer but plenty "flexy." The replacement spring hangers are sturdy and weld up nicely. All you have to do is fab an upper shock mount and boom, done. Everything is a quick web order away and not special order.

Alternatively just copy the gold standard of off road trailers: military quarter ton. That's just regular old flat fender Jeep front stuff. Also easily obtained from various vendors.

I see why folks might be interested in more exotic stuff but all things being equal, simpler is usually better.

 

[billiebob]

I tend to agree when it comes to the actual suspension part. The two benefits I see are increased clearance in the center (not getting hung up on an axle tube), and being able to minimize the trailer width by needing less clearance from the inside of the tire to the frame.

I have trouble seeing value here. Unless the tow vehicle has portal axles the limiting factors are the tow vehicle axles, transmission, transfer case. And I'm not sure how the tire gets to run closer to the frame. The tires on my straight tube axle on leaf springs run within an inch of the frame rails. How much closer would you want to run?

 

[high-and-dry]

Well we can all agree to disagree or keep swinging our purses at each other.

I went with torflex, because its not a bouncey stock trailer spring axle setup. Yes I could have gone to different springs and shocks, but that is not off the shelf, its semi custom. Yes I know parts are not hard to get, but what spring do I want, one from a jeep, one from a chevy s10? Its not like there is a ton of info out there, there is info but I have never seen a list that says if your trailer weighs this, and you want this length spring get this spring from this vehicle.

Torflex is off the shelf so is timbren and I was thinking about both.

Why does one of the trailer axle companies not make an independent swing arm set up using coil springs. Easy to customize just by saying use X spring for Y weight. Set it up with shocks and everything, make it bolt or weld on. Oh because it would cost even more, restrict frame design even more, and never be perfect just like every other system out now ( as in no system is perfect now ).

The biggest design issue with the swing arm is the normal two frame members we are used to attaching axles to are not what it mounts to. you need a big heavy duty cross member very solidly attached to the frame members.