Shocks?

[Karebru]

I watch lawn service trailers banging down the road, think about all the stuff in a camper being jolted around, and wonder about installing shock absorbers.
Is there a reason why they aren't common place?
I would think that they would help with the tow vehicle ride too.

[flboy]

My guess is that they would increase cost of trailer and nobody is riding back there to complain about the ride. Certainly they would improve tire contact to the road and handling as well as ride. I think some higher end trailers do have them. All about costs I am willing to bet.

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[onehoser]

installing shocks is on my wish list too. most of my milage is on paved roads but we camp on crown land and use fire and logging roads to access the campsites, which can get pretty nasty after heavy rains.

[Karebru]

A quick search reveals bolt on kits.
Seems like it would make life easier for home type appliances that aren't designed to be bouncing around.
Help with tire wear too.

[jmanscotch]

You're not wrong, better leaf springs AND shocks has made my trailer tow like a dream, specifically off road but on road too.

The main issue with most stock trailer suspensions is it's made for smooth highway roads and for the max capacity weight. If you've ever rode in an empty dump truck or even a heavy duty F350 that's not loaded down, you understand how crappy the ride is with suspension designed for carrying x amount of weight...when it isn't carrying that heavy load.

On my trailer, I didn't want to watch it bounce around behind me off road, much like you mentioned seeing. So, I replaced the leaf springs with longer and softer Jeep CJ-7 springs and shocks and boy is it *the nicest* handling trailer I've ever towed. Around town, going through dips in the side street, over speed bumps and even just pulling into my alleyway where it's quite bumpy...the trailer just absorbs the bumps and is so anti-dramatic back there.

I HIGHLY recommend it, even if you just do shocks, I bet you'd see a big difference, but I do personally believe that changing the leaf springs from the short, high capacity stock ones (as seen in the first pic below, still installed with the Jeep springs installed showing size comparison) is the biggest changing factor to a nice ride.

[aggie79]

All about costs I am willing to bet.

...and complexity...four shocks for a tandem axle trailer!

[flboy]

No more or less complex than 1 axle.. just more harware I'd think?

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[Karebru]

My trailer is definitely over springed to ride well empty, and I'm trying not to add too much weight with my build.
One more thing to consider doing down the road.

[onehoser]

i had an old tent trailer that came with shock absorbers that i converted to a utility trailer, it towed like it floated on air, i kept forgetting that it was even there.

[working on it]

• I approached the "shocks or not" problem from a different perspective: cushioning the ride was secondary to protecting the suspension itself. I made an alternative device to serve both functions simultaneously, which attaches to the frame with one bolt (constantly held in place by the axle, too), and can be removed or modified (for a softer ride) in minutes. Just another alternative, if you care to try it.

  from http://www.tnttt.com/viewtopic.php?f=39&t=66773&hilit=+bumpstop#p1198094...both times that I've experienced broken leaf springs (and the one-unmentioned shackle tear-off) there was no bumpstop to cushion/limit the flexing of the spring past its' working arc limits. In the case of Dave's spring breakage, the leaf spring had nothing limiting it from flattening out, or even reversing its' normal arced shape (except for the shock bottoming out), resulting in a severe jolt, and breakage. Now, even Timbren recognizes the problems of over-travel in their suspension, and sees the need to "progressively" absorb the energy before the absolute "stop".

  

  Timbren active bumpstops.PNG (199.43 KiB) Viewed 4274 times

  I chose not to use shock absorbers with my new leaf spring suspension (with relatively little travel), reasoning that the shock absorbers couldn't absorb enough energy in their limited motion to do much good before their absolute stop was reached.And, I was going to add a bumpstop to prevent the possible overtravel of the leaves past the flattened arc stage. So, I combined the functions of shock absorber and bumpstop into one, using a Daystar progressive bumpstop, made of resilient polyurethane, as an active part of the system (always in contact with, and following the motion of the axle); sorta like Timbren does with their component. I described my "active bumpstop suspension" in my thread: http://www.tnttt.com/viewtopic.php?f=35&t=59570#p1075076. I modified the Daystar bumpstop to be softer-acting (by cutting away the hard "bump" of the top of the piece, and curved the remaining body to slip-fit between my axle and frame (at full droop of the springs). With the top part of bumpstop so modified, the remainder relies on the two lower "ligaments" to progressively flatten out, before compression into the bottom layer, when the overtravel is finally prevented.

  

  Daystar progressive bumpstops ku09016bk.jpg (62.68 KiB) Viewed 4278 times

  I wondered how well it would work, as did many doubters on the forum, but I think it proved itself when I encountered a large chughole in the road at 75 mph. My truck and trailer both got bounced into the air, with my truck tires being the only damaged parts afterwards. In normal driving situations, I really haven't noticed any of the trailer bounce that I should be seeing, as a result of using too stiff of springs. In any case, the bumpstop at least kept the leaves from overflexing, preventing breakage. If I ever soften the suspension, and/or add conventional shock absorbers (if suspension travel becomes greatly increased), I will still use some form of progressive bumpstop to limit overtravel. I try different things, sometimes re-purposed from originally designed function, to do what I need them to. Sometimes it works....and

  my trailer now weighs 2025 ls, and I use a homebuilt version of Timbren's Active Off-Road Bumpstop (designed by me, and built and installed years before they started selling their's). from their website>>> Active Off-Road Bumpstops---Active Off-Road Bumpstops help you take control of your suspension travel. They’re designed with a progressive spring rate that can absorb the energy created when they “bottom out.” In other words, they allow for a smoother ride when they “bump” down on the axle. My bumpstops eliminate the roughness associated with using the leaf springs, being over capacity, by 32.5% (or 42% as compared to the axle capacity, itself), since I made them more flexible, and always acting upon spring travel, not just when "bottoming-out". I may, at some future date, get the lighter springs, if I unload the trailer's current load, but for now, they work fine, as-is.

• 

  my active bumpstop suspension is always active.jpg (135.87 KiB) Viewed 4278 times

[aggie79]

No more or less complex than 1 axle.. just more harware I'd think?

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I was thinking that you may have geometry issues with shocks on a tandem axle trailer with the extra movement of the equalizer/rocker.

For tandem axle trailers, maybe you could get some of the shock absorber characteristics by using an aftermarket dampening equalizer:
https://www.etrailer.com/Trailer-Suspension/Dexter-Axle/K71-652-00.html or https://www.etrailer.com/Trailer-Suspension/Lippert-Components/LC314336.html.

[hankaye]

aggie79, Howdy;

Thanks for providing those 2 links. Over on the RV forum I spend some time on I've read
more about the Dexter then the Lippert. Could be users choice, preference, who knows ...
Everyone has had good things to say but for most the reason for switching was something
broke on the factory version. As they are generally wrestling with something 3 or 4 times
the size and weight of our Cargo Trailers not much is said about quality of the ride after
the switch. Just some fodder for the thought box.

hank

[Karebru]

aggie79, Howdy;

Thanks for providing those 2 links. Over on the RV forum I spend some time on I've read
more about the Dexter then the Lippert. Could be users choice, preference, who knows ...
Everyone has had good things to say but for most the reason for switching was something
broke on the factory version. As they are generally wrestling with something 3 or 4 times
the size and weight of our Cargo Trailers not much is said about quality of the ride after
the switch. Just some fodder for the thought box.

hank

Yeah. It looks like actually achieving a better ride, especially on a twin-axle, is a little more complicated than just a few bolt on parts.
...Still worth looking in to, though.

[working on it]

...It looks like actually achieving a better ride, especially on a twin-axle, is a little more complicated than just a few bolt on parts....

• Not so much, from my perspective, and thinking outside the box....FYI, in my previous post, I described how my home-built version of the Timbren Active Off-road Bumpstops was designed for use on my someday-soon offroad trailer; it was designed to be easily softened, if the ride turned out too harsh, by snipping the center filament, whereas the Timbren design "donut" would have to be replaced with a new/softer piece of rubber. My post showed a picture with just the "donuts", and without the U-bolt. over-axle mounting pieces. I see no reason that the Timbren (or my version) active bumpstop wouldn't work if properly positioned on a tandem axle trailer, and if the proper "spring rate ?", or rubber resilience vs. durometer, is chosen to match the trailer specs, or to suit the owner's preferences. I'm sure Timbren has tons of data comparing different sets of the rubber "donut", and could get pretty close to perfect match for any desired load, or desired feel, but I just made mine to see if they would work, on my one-off TTT.
• The trailer is heavier than most/all of comparable size, extra steel reinforcement was added to the frame so I could use heavy-duty suspension components, and the springs are rated at 3k lbs--1.5x the road weight, and 85% of the axle rating-- so I had very little spring travel anyway, and I wanted to cushion the flex, and prevent over-flexing above all, so my experimental approach was just what I needed. I could not find any sort of shock absorber that would meet with my special situation, and I even considered a Firestone Ride-Right air suspension (I had used Air Lift Drag Bags before, and wasn't too happy with them), air shocks (same story), coil-over racing shocks (too much $$$), and even tried to find compact Load-Levellers (I have used them on my last 4 trucks). Nothing fit my requirements, so I made my own solution. If ever I start using my car-hauler trailer (tandem-axle) again, on a regular basis, I will look into installing more of my active bumpstops (in 4 places), or get the Timbren version...it should help with the jarring ride, and prevent broken springs from over-flexing (I've had a couple on the car-hauler, and one on my TTT, before the axle re-build).

• 

  timbren bolt-on active offroad bumpstops.JPG (92.92 KiB) Viewed 4085 times

  this is the bolt-on Timbren kit, with axle U-bolts already attached

[Karebru]

Working on it, I might be misunderstanding where you're coming from.
If I do anything it will be in an attempt to soften my suspension. I'm looking for a better highway ride and not worried about off road issues.
I'm way over springed for what I anticipate my final curb weight to be.
I would have probably been fine with a single axel under my 7×16, but I decided to take the duellie on the lot.
Floating down the highway like an old Cadillac would be perfect.