What problems are common with rough road towing?

[deepmud]

hmm. I don't think we'll get much from RTI ramp info on 4x4's - those numbers are about flex across a frame vs. wheelbase. A long wheelbase vehicle will tend to have worse RTI index, other things being equal. RTI is not relevant to trailers - as mentioned, at low speeds, trailers will no suspension have great RTI numbers.

We can't be worrying about how well a trailer will tilt on a ramp. We can worry how well the suspension will hold up on dirt roads, with pot holes, at 45 mph - and leaf suspension USUALLY will hold up well ....

However - it will USUALLY transmit more jolts/bumps/vibration to your trailer. Your cups and saucers will bounce around more, you beer may be fizzier.

It's a matter of unsprung weight AND your springs AND your shock valving, assuming you have shocks. Bigger tires help BUT increase unsprung weight - you can over do big tires.

I have pics of failed leaf suspensions - one a rear Bronco spring that that snapped - one a heavily built off-road trailer behind a Rover (with coil springs on solid axle..... ) - both vehicles required welding to repair in the field ( the trailer repairs happened a couple more times for the Wolf Expedition but to be fair he isn't a mechanic, and depended on 3rd World repairs each time ).

Adventure Trailers found that the rubber torsion spring suspensions failed with dust getting in them - but what failures have been seen with the newer design trailing arm, with air bags or leaf springs? Does anyone have experience or heard of them cracking welds or something?

I don't think repair when broken is a good reason to go with one design either - I would hope you build or buy with the idea that it will hold up for the application.

Paul, the ones you have seen failed - what type? Rubber torsion? Or?

[PaulC]

hmm. I don't think we'll get much from RTI ramp info on 4x4's - those numbers are about flex across a frame vs. wheelbase. A long wheelbase vehicle will tend to have worse RTI index, other things being equal. RTI is not relevant to trailers - as mentioned, at low speeds, trailers will no suspension have great RTI numbers.

We can't be worrying about how well a trailer will tilt on a ramp. We can worry how well the suspension will hold up on dirt roads, with pot holes, at 45 mph - and leaf suspension USUALLY will hold up well ....

However - it will USUALLY transmit more jolts/bumps/vibration to your trailer. Your cups and saucers will bounce around more, you beer may be fizzier.

It's a matter of unsprung weight AND your springs AND your shock valving, assuming you have shocks. Bigger tires help BUT increase unsprung weight - you can over do big tires.

I have pics of failed leaf suspensions - one a rear Bronco spring that that snapped - one a heavily built off-road trailer behind a Rover (with coil springs on solid axle..... ) - both vehicles required welding to repair in the field ( the trailer repairs happened a couple more times for the Wolf Expedition but to be fair he isn't a mechanic, and depended on 3rd World repairs each time ).

Adventure Trailers found that the rubber torsion spring suspensions failed with dust getting in them - but what failures have been seen with the newer design trailing arm, with air bags or leaf springs? Does anyone have experience or heard of them cracking welds or something?

I don't think repair when broken is a good reason to go with one design either - I would hope you build or buy with the idea that it will hold up for the application.

Paul, the ones you have seen failed - what type? Rubber torsion? Or?

Two that come to mind were an independent leaf ( Yes That's right)that the pivot bushes had let go on and the other was independent coil that had broken pins on both sides. Not a pretty sight, I can tell you.

Cheers
Paul

[StormRider]

Look lets stop playing political games here....

Political games? You threw out a challenge:

Leaf spring suspensions are not capable of the same type or rainge of articulation that a well designed independent system is.

I showed otherwise.

Wranglers were not built in 1996 It was a dead year

YJs produced in early 1996 were sold as 1995 model years, but featured a few new parts not seen on any earlier YJ. [/quote]http://en.wikipedia.org/wiki/Jeep_Wrangler

In point of fact none of the rigs you show stats for have leaf spring suspensions.

a 350 RTI score for a "96" wrangler is consistent with other sources for a stock leaf spring YJ.

Now look up the numbers for a 1997 H1 not a 1993
Then a modifyed 1997 H1.

The H1 suspension was not changed between 93 and 97. If you wish to prove that suspension mods will allow a H1 to compete with a stock 97 TJ, you can look it up and provide the source.

Back to trailers none of this has anything to do with the fact that the independents are a better idea on a trailer.

I never disagreed with that statement. It's a cost/complexity decision for the builder/buyer.

So stock vs. stock leaf springs do not compare to independants

....All I ever sed
Look I'm not a Huimmer fan. In fact I own several Jeeps ALL WITH LEAF SPRINGS. All highly modded . It's one of my passions . If we want to talk about Tow rig suspensions lets do it somewhere else.

You show a pic of a H1 at almost full flex that's clearing a maybe 12" rock, and suggest that independent suspension is better than a solid axle leaf spring? I suggest you do take that discussion to a dedicated offroad discussion forum, such as [url]Pirate4x4.com[/url] and let me know where the thread is.

Lets get back to trailers..... ....Boxcar... :oops:

Enjoy the rest of this thread, I'll not be participating because it's apparent to me that well researched and presented information that doesn't agree with your opinion must be politics and incorrect.

[boxcar]

Notice the H1 has a driver !!!!! Notice the H1 is moving!!!! Hitting an obstical and is still level. And by the way. If you have ever driven an H1 in the field ( Army reserves) that is no were near full flex (look at the rear suspension).But it is a pig compared to a TJ. And also notice the only rig that you list that has leafs is the (fabled) 1996 yj and it has lower nuimbers. And is probably a quarter the weight of an H1. If it had ever ben built. (it was not ) This is in the relm of Jeep lore. A diferent topic all together....
Look all I was getting at with my remark about pollitics was that you were not comparing apples to apples( stock vs stock.) As some polititions do. Kind of beating around the bush.
I am sory it was a cheap shot and I should have worded it diferently.
Resurch is more than finding one sorce that agrees with your point of view and gloming on to it. If you truly resurch this topic you will find that most people and manufacturers tend to agree that independents tend to out perform leaf spring suspensions. In point of fact the only industry still using them (leafs) on a reguler basis are trailer manufaturers....and some truck manufaturers..
Paul I have seen a few pivot pin failiures myself. In boath cases it was caused by poor quality ( low grade ) bolts being used insted of grade 8 or 10 hardened pins. I have also seen many spring mounts tear out of leaf srung trailers. And I have repaired many broken leafs. Due to fatigue.
It all comes down to the ride. Soft and smooth vs. harsh an bouncy. The harshness of leafs is what causes them to fail more often than independants. The only cure to the harsh ride is to under spring the trailer or to go to longer springs. This causes more flex in the spring axcelerating the fatigue problem and then early failure. It also will place a greater load on the trailer frame at the suspension mounting point (torn out spring mounts) Adventure trailer has done a bunch of real world testing on this topic and has gone to Independents . I bow to there expertise on this topic. ....Boxcar...

[deepmud]

The Internet is a funny place - you can find yourself arguing points with people who agree with your point while they are trying to make another one of their own.

I think we can take some good information from all this stuff still.

One - articulation as seen on a 4x4, in form of RTI, isn't relevant on a trailer. A trailer can be run up a ramp 'till it falls of the end or rolls over, or binds the hitch if you have the type that binds, even if the trailer has a solid axle welded to the frame ( my 4x4 has exactly that under each end actually, and can put one tire 4 feet in the air while leaving 3 on the ground) .
Suspension travel, and spring rate, rebound, and unsprung weight - we could talk some about that some more yet. We've just scratched the surface of that discussion here so far. However - most the points seem to be about ease of build and repair. Worthy of discussion, but perhaps not answering the question?

Two - Leaf spring suspensions are easy(er) to build, easy(er) to replace - as a general rule, I think that is a true statement. Anything can be under-engineered, and fail, but still it's pretty easy to weld a leaf spring system to a frame.

Three - Trailers that absorb shock with their suspensions will tend to be easier on the contents of the trailer - and springs that are soft, whether leaf or coil, solid axle or something else, will do that better than springs that are stiff and hard to flex.

Four - The lower the unsprung weight to sprung weight ratio is, the better for smooth ride - but that isn't the ONLY consideration or we might all be towing hovercrafts.

Five - there's that saying, about winning Internet arguments.......................

I'm saying that your goal shouldn't be to RIGHT, but to put forth your ideas.

Be OK with someone disagreeing - it won't mean you are WRONG.

Well - I've been TOTALLY wrong before.....there's a thread on Pirate 4x4 about Opposed 4 Piston brake calipers vs. Single Piston floating calipers...oy!.........lol

OH - and that time I told someone that long shocks on each corner of a 4x4 was a dumb idea ( he said "like motorcycle forks, both a shock and a spring..."....I said "oh look you've invented the McPherson Strut!" what a smart ass I was, killed that discussion real quick.........that was like 1989?...the Internet was all text, and it was a mailing list.....lol .... Notice the coilovers on those rock-racers poster earlier in this thread?...

Just put out your experience and thoughts and let the rest go. It is just the Internet here. It's lots of fun, and there IS good information to be had, but in the end it's only a small part of the world.

[boxcar]

Good call..Boxcar...

[meach4x4]

Lots of info here. Most of it is useful, and quite a bit of that was on topic. I just scanned the thread, and would like to add a couple of points:

1. Driving slow on rough roads is great advice. It becomes a logistical problem when you are driving several hundred miles of dirt road between camping spots. It isn't always practical to drive at a speed where there isn't repetitive vibration. On washboard/"corrugated" roads, you may be better off to find a good speed where the ride is more comfortable than slower or higher speeds.

2. In order to avoid shaking your load and your trailer to pieces, it is a good idea to invest in a good independent suspension, as the rebound factor that was mentioned, and the vibration effect will be less if you have less unsprung weight. As has been mentioned earlier, Adventure trailers has done the research and development on this. Their trailers are well recognised as the most capable over rough terrain at higher driving speeds.

There are several other considerations I had while building my back country trailer:

For starters, keep your center of gravity low. It will make your trailer more stable on rough road and will make the trailer less tippy on curves and off camber roads. Put all the heavy parts, like batteries and liquid containers as low as possible. Along the same lines keep heavy loads between the axles. You don't want your trailer to get tail happy when you are crossing undulating ground.

Build your trailer strong and light. It is a lot easier to control a lighter trailer, and the repetitive vibration from washboard is a lot less destructive if the vibrating parts are lighter.

Spring your trailer appropriately for the load. Too little spring can be disastrous, but also too much spring can be just as bad. This is where the air bag suspension is good, as you can adjust for any load within the range of the bags.

Use plenty of loctite on screws. Vibration on washboard roads can loosen the screws. I consider using a full vinyl wrap to "lock" external body screws.

Make sure to have solid tie down points to secure your load.

Use nylon nets and click straps to secure loads instead of bungees and/or bungee nets tht stretch. The problem with bungees for securing loads is that they will amplify repetitive movement as the bungee stretches and contracts under a load. A proper nylon strap and strap net will not move once it is tight.

Rather than use large flat tanks to carry luquids, consider multiple smaller tanks so that the shifting of the liquids from side to side doesn't rock your trailer unnecessarily. If you do want to go with large tanks, they should be baffled to decrease load shifts.

Be careful to pack your load so that it won't be bouncing around. It is all well and good to carry your gear in nice totes, like pelican boxes or less expensive Roughneck totes, but when you are loading the totes up, fill them up and use towels, dish cloths, wipes, toilet paper, paper towels, and wash rags as packing material to keep the load inside the tote from shifting and bouncing around.

The more you can do to keep your load low and keep it from shifting and bouncing will help your trailer's suspension from being overworked.

I hope this info is helpful, and not too boring.

Gil

[deepmud]

so I found a neat video posted on the Expedition Portal, that illustrates why I advocate Independent suspension. Observer the tow rig getting it's tires bounced clear off the ground over chatter bumps, while the Tvan behaves nice and keeps the tires on the ground.

http://www.youtube.com/watch?v=oa4BgNF8 ... r_embedded

[deepmud]

Last weekend I drove/camped the Denali Hiway with the ol' Green Trailer.



And I'd like to add this thought - if your trailer can ride better than your tow rig ( the frost heaves are nasty near Paxton Lake) then you likely will not break/smash/toss around your stuff.