Shocks?

[Tomterrific]

Leaf springs have a certain amount of friction shock built in but not enough to act as a shock. In my opinion, shocks are better than no shocks. Brakes are better than no brakes. If it is worth the hassle for a builder then I say, "Do it!"

Tt

[ntsqd]

That is what most trailer spring mfg's count on, they're short, stiff and have enough internal friction to damp the minimal movement they do make.

[Squigie]

I think that the change was made to eliminate the typical clanks and creaks inherent to leaf springs. They may be annoying to us, but they could be deadly to the military.

Any military vehicle towing the trailer is going to be louder than some creaky leaf springs.
I don't see squeaks and creaks being a factor, at all.

Have you ever been around a military movement? It is a cacophony of diesel engines, bucking and banging pintle hitches, vehicle bodies and frames straining under stress, chains swaying and slapping, tailgates banging, rocks being launched into undercarriages, and trucks, trailers, and overloaded humvees banging and scraping on the road they're destroying.

Heck, some of the trucks (not heavy equipment or tracked vehicles, just trucks) currently used by the US military are so loud that passengers are required to wear hearing protection, and drivers get headsets so they can communicate with their co-driver in the cab.

If you wanted *me* to pick a single reason why they went with Torflex axles, it would be weight. Saved weight means more payload, and/or less fuel to burn. In military ground logistics, fuel is priority number one. You don't even worry about water or food, before fuel. Because, without fuel, you can't move the troops, let alone water and food.
Fuel is everything. Weight burns fuel. Saving weight saves fuel. Fuel is everything. Adding payload, for when it can be used, is a nice bonus.
...And that's not even touching on the ability to move more equipment on the same transports (air and sea, in particular), if they are lighter weight.

[ntsqd]

I was thinking more in a small troop movement, not a massive convoy. As to the pintle hitches clanking I've found that when the lunette ring is sized correctly that mine don't make much noise at all. I won't say that they are quiet, but they are not noisy at all.

Our TrailBlazer on the way home from it's last outing, the Parker 425:


The rotating lunette assembly used in the pic above:

For a sense of scale those are 7" long 9/16" bolts holding the plate to the weldment.

[gudmund]

still miss the Dexter torsion axle I had had on my last trailer - this new trailer came with leaf springs which seem to be working out fine now. My first change was getting rid of the 'China' made ST trailer tires it came with when I bought it two years ago, I went with US made car tires which helped the ride out "immensely"! Have now added one of Sumo's trailer rubber (bump-stop) spring kit's which 'they' say will work like shocks - so far they seem to be working out good - they were a very easy 'install' and also helped by adding just a bit more more fender clearance - gained about a 1/4-3/8 inch or so, along with what seems to be alot less bottoming out when loaded now. (there had been just a touch of fender bump/rub before on the passenger side) Cost for the set-up was just under $190 for the kit/pair of them using Sumo's 30% off coupon last winter.

[ntsqd]

Bare in mind that one of my main hobbies is desert racing, and that kind of racing is all about the shocks and the tune on them. Not the HP of the engine or where the Instant Roll Center of the suspension is. Shock tuning is what makes or breaks a winning desert race vehicle. Probably gives me a skewed point of view, maybe even a jaundiced one. That said, I doubt that a rubber 'spring' will do much for damping the suspension's motion. However, there is no arguing with them if they are working for your use.

[gudmund]

That argument would have to be taken up with "Sumo Springs", I was just 'quoting' what they say the selling point is with this setup/ product. I do see how they will work as a 'bump-stop' cushioning pad, but as a 'true' shock? No, maybe somewhat on the compression 'input', but for the 'out-bound' control?, not much like a 'real' shock works. The main thing is these seem to be helping with the bottoming out when loaded and the touch of fender clearance problem I had been having. (as I said, I would have rather have had the Dexter Torsion of the last trailer I had, but this is now what it is and I hope what I have added here will make things more livable for the long run (or until I can afford the 'update' back to a Dexter Torsion Bar setup) Take care & stay safe out there............. PS many moons have passed since my days of working with shocks/suspension = but with me it was NEVER off-roading - was either for road handling (50-50's) or them front 90-10's with the 'slip' joint bushing's/no stab bar when drag racing = as long as you could keep it going straight - things were good..........but when using them 'wrinkle-wall's', it got a little hairy a few times, especially when trying to slow down .................early 70's, probably better 'stuff' being used nowadays ...................

[tony.latham]

My 2007 Tacoma had a bit of butt-sag when hitched up to ol' Flash.



I installed the Sumo "springs" in it and it solved the sag. I think it may have smoothed the ride out a bit too.

I was going to add them to my 2016, but I don't have the sag so never did.

I thought they were a great product. Probably a good addition to traditional spring-trailer supsension.

Tony

[working on it]

Leaf springs have a certain amount of friction shock built in but not enough to act as a shock.

That is what most trailer spring mfg's count on, they're short, stiff and have enough internal friction to damp the minimal movement they do make.

* My 25.25" long leaf springs (3000 lb set, on a 3500 lb axle) only droop <1.5" when the trailer is lifted off the ground, preventing use of "long-travel" shocks of any sort, but there is a need for bump stop protection from bottoming out (or worse, stressing leaves and shackles by flattening out on severe bumps).

* Sumo Trailer Helper Springs ($215 @Etrailer), as used by gudmund and tony.latham, or Timbren Active Off-Road Bumpstops ($225 @Etrailer) would've done the job for most trailers, but the small amount of travel in my suspension required a custom solution. I didn't want to cut down Sumo's to fit, and I was unaware that Timbren had that product, which would've needed modifications to fit, anyway). Thus, I fabricated my own, from Daystar polyurethane "progressive" bumpstops ($60@Amazon) and $7 worth of 2"x 2" x 1/4" steel angle. If it hadn't worked as I envisioned, then I only would be out a fraction of the cost of the others.

* To fabricate http://www.tnttt.com/viewtopic.php?f=35&t=59570, I cut-off the hard cap atop the bump stops, used a holesaw to scoop out a recess to form-fit the 2.375" axle, and welded the bumpstops to the 18" long pieces of angle iron, so I could bolt them to the newly-reinforced frame just above the axle. It was a snug fit, and felt quite firm, with no movement noticeable when back on the ground. If I ever detected a harsh ride on the road, I could still soften it up by cutting a cross-linked filament. After several years of use, there's been no need to do so. I suppose any harshness is absorbed by the "flotation"-type LT tires I use (27 x 8.5-14LT General Grabber AT2).

[ntsqd]

Although I fabricated a couple drag racers with suspension for others, my days in crewing on a drag racer were all spent in Super Comp and TAD. Have no idea what they're doing these days (those 'slipper' dragster chassis were just coming in as I left drag racing), but given the cross-over that I've seen of desert racing damper knowledge & tech bleeding into other racing arenas I'll bet that it is way more complicated than it used to be.

I'm probably too anal about using the correct names for parts and systems (what you get for allowing an Engineer, in the Spectrum, into the conversation), but a bump-stop is not a shock absorber. Don't care how it has been modified, it is not a shock absorber. A shock absorber is properly called a "Damper" because it dampens the motion of the spring-mass (axle, wheels, tires, brakes) system. Usually by converting the motion energy in the system into heat and radiating that into the air.

A bump-stop's job is to slow down the suspension in its last bit of travel so that harsh metal to metal contact does not happen. They are a rapidly rising rate spring. Most think of springs as being inherently metal, but that is very untrue. Older MTB forks and stamping dies have used Urethane springs for a long time. Those springs first used in the MTB forks were urethane die springs. Those are two examples that I know of, I'm quite sure that there are others and likely many others that I don't know about.

Again, labeling issues aside, if what you've built is doing what you need it to do and not behaving badly or unexpectedly then why would you change it?

[gudmund]

and yes to "working on it" as you may have noticed in the posted picture I attached, yes I did end up cutting one inch off of the 'Sumo' 4 inch tall rubber spring. (its now 3 inches tall with a 1/4 inch of preload per instructions) ..........................

[working on it]

and yes to "working on it" as you may have noticed in the posted picture I attached, yes I did end up cutting one inch off of the 'Sumo' 4 inch tall rubber spring. (its now 3 inches tall with a 1/4 inch of preload per instructions) ..........................

homemade active suspension... modified Daystar vs modified Sumo.jpg (87.75 KiB) Viewed 3265 times

* My Daystar piece is about 1.25" shorter than it was originally, now about the same height as your Sumo, and with about 0.5" of preload, after being moved into place with a BFH (there were no instructions as I was using the product in an entirely different manner than intended). Both systems stay in close contact with frame and axle/spring assemblies (your Sumo is attached to the sprig, whereas mine is attached to the frame), and the progressive compression nature of each removes the danger of instantaneous/complete bottoming-out, that bumpstops alone (sans shock absorbers) would provide. It's a way to help out out our trailers with insufficient axle travel to utilize true shock absorbers.

[gudmund]

I can live with that - nice comparison photo set and explanation.

[ntsqd]

If the axle moves at all a shock can help. Just because the axle can only move 1" in it's given use doesn't mean that you have to use a shock with only 1" of travel. You're obviously not going to find a shock with that short of a stroke, and that's OK. Just use the shortest shock that you can find. Most shock mfg's have a listing of their p/n's respective extended and compressed lengths. For instance, this is Rancho's: https://www.gorancho.com/downloads/prod ... _specs.pdf

Think about spring rates, the units are load over compression (lbs./in usually) So if you have a 2500 lbs./in spring then it compresses one inch with 2500 lbs. on it. With only 1250 lbs. it only compresses 1/2", but with 5000 lbs. on it it will compress 2" I think that is obvious, but I mention it just in case it is not.

Suppose a TD weighs 1200 lbs. and has those 2500 lbs/in springs under it. The axle is rarely going to move at all because it would take 5000 lbs. to compress both springs 1". The beer is going to be foamy and the eggs will only be good for scrambled, AFTER you get all of the shell chunks out of them. Lets say that we replace those springs with 500 lbs/in springs. Now the trailer's weight will compress the springs ~1.5" and the axle will move much more freely when a tire hits a bump. Downside is that ride height will vary a lot more with load. Upside is that the beer won't be foamy and you can have the eggs sunny side up if you so desire. If those 500 lbs./in springs start out with 1.5" more arch in them than the 2500 lbs./in springs have then the resulting ride height for the unloaded trailer will be the same.
With trailer springs that have more than one leaf in them one way to get a softer spring rate is to remove leaves from the springs. The shorter the leaf, the stiffer it is. With either the cut down urethane bump-stop or the Sumo spring in place I suspect that most TDs could use only the main leaf if they had shock absorbers. Running that light of a spring rate w/o shocks would very likely result in dangerous sway.

[mtbikernate]

I have a basic leaf spring arrangement in my trailer. Haven't had any major issues, but I have had at least one bottom-out incident where the axle contacted the frame. Don't know for sure when it happened, but I see the evidence of it if I look under the trailer.

I was looking for a solution to prevent this from occurring again, mostly, while avoiding a "hard" bump stop. I won't argue with a touch more ride height and maybe slightly smoother compression events, either.

I actually turned up working on it's modified daystar bumpstops on expedition portal and was considering a similar solution.

After speaking with a SumoSprings rep (and a Timbren rep), I chose to buy the blue, lighter duty Trailer SumoSprings.

https://www.superspringsinternational.c ... SS-106-40/

I have just at 6" of clearance between my leafs and the frame (which is within spec for the sumos), so I shouldn't need to make any modifications to these to get them to work. For me, a bolt-on solution that I could install without modifying was worth spending a bit more.

I'll also be replacing the bias ply ST tires with 27x8.5x14 AT tires (going with the less expensive Maxtrek SU-800 tires instead of the General Grabbers, the only other model in AT variety appears to be a Kenda Klever, which seems even harder to find, though there are quite a few more MT options).

Between those two changes, I expect that my trailer will be able to ride a bit smoother on gravel roads (mostly from the ability to air down the tires, and the newly gained tire flex). That's the extent of the "off-roading" my trailer will be seeing.