My Trailer Build Plan W/Questions

[LandCruiserPhil]

Phil,
IIRC, one of the Dexter pages that showed the axle with leaf spring options did show parabolic as one of the options. Did not inquire further, but IIRC it's one of those previously cited here.

One reason I didn't look further was I've always seen them used in apps where one or both of thse applied, cheap or space limits. I presume if you're recommending, they're up to trail use, but do you need to buy carefully to ensure that's the case?

Asking the question that way, because WYSIWYG with a leaf spring, while things like parabolics, torsion bars, etc are a bit too arcane to judge by just looking at them. In other words, I'd have no problem taking the Dexter leafs if they were long enough, which IIRC they weren't being like 26"? Where longer sounds better to me per my experience with our 1/4 ton (36" spring length and IIRC most others are similar length?) But I'd be wary of the other option. Then again, maybe they're all pretty bullet proof nowadays?

Not a recommendation just another option. I like and run torsion suspension for my light weight trailer. I was educated and schooled on the trail by Chris at Campa USA Trailers that travel for off road trailers is over-rated. Correct spring rate is super important for the type of roads and terrain our trailer are built for. One thing to be aware of as you look at long springs is when they load up you need to control the rebound or you have problems keeping it on its wheels and tracking. I ran into this big time with AT trailers air bag suspension, a nightmare off road.

 

[greentruck]

Just plain old tubular shocks on my junk, so pretty basic. LFD hasn't mentioned any, but I presume he's planning on it. Fortunately, the KM2s on our trailer can be aired way down even loaded to help with that, but still an E rated tire IIRC, so gonna be some sidewall stiffness even for a radial when lightly loaded as they are. I need to do more testing on this.

I'd expect some of the rebound is load dependent. Keep it heavy and things do tame some, but also a reminder to not overspring. LFD's plan to lose some leaves if the springs he finds are too stiff should help with that up to a point.

 

[titanpat57]

Not a recommendation just another option. I like and run torsion suspension for my light weight trailer. I was educated and schooled on the trail by Chris at Campa USA Trailers that travel for off road trailers is over-rated. Correct spring rate is super important for the type of roads and terrain our trailer are built for. One thing to be aware of as you look at long springs is when they load up you need to control the rebound or you have problems keeping it on its wheels and tracking. I ran into this big time with AT trailers air bag suspension, a nightmare off road.

The first time I met Chris we were stopped for gas about 30 miles shy of the Vermont Overland Rally. He followed me pulling the trailer in his Mog, to the event.

Once we got set up he came down and talked at length about the how's and whys of suspensions.....an extremely informative session that's for sure. I was ready to go out get slipper springs for the trailer after that.

 

[LandCruiserPhil]

The first time I met Chris we were stopped for gas about 30 miles shy of the Vermont Overland Rally. He followed me pulling the trailer in his Mog, to the event.

Once we got set up he came down and talked at length about the how's and whys of suspensions.....an extremely informative session that's for sure. I was ready to go out get slipper springs for the trailer after that.

My education was earlier with both his Jeep & trailer and Tacoma & trailer on a multi day expo with the Toyota trail team. He made our AT trailer look worthless but was very nice about it, great guy. I do agree with you on slipper springs they were my next choice after torsion.

 

[LFD2037]

Just plain old tubular shocks on my junk, so pretty basic. LFD hasn't mentioned any, but I presume he's planning on it. Fortunately, the KM2s on our trailer can be aired way down even loaded to help with that, but still an E rated tire IIRC, so gonna be some sidewall stiffness even for a radial when lightly loaded as they are. I need to do more testing on this.

I'd expect some of the rebound is load dependent. Keep it heavy and things do tame some, but also a reminder to not overspring. LFD's plan to lose some leaves if the springs he finds are too stiff should help with that up to a point.

I will be going with shocks.

I read somewhere, can't remember, where people highly advises against slipper springs for an off road trailer. Is that not the case?

 

[titanpat57]

I will be going with shocks.

I read somewhere, can't remember, where people highly advises against slipper springs for an off road trailer. Is that not the case?

If I understood it correctly, because of the slipper spring design, and lack of rear mounting eye on the spring itself, it allows the energy to disperse, as opposed to reload, and transfer back to the other spring.

That's where you get the unwanted transfer of built up energy (ie. compression), which in higher speeds, leads to death wobble.

I hope I explained that right, and it makes sense.

 

[ntsqd]

Air springs usually have a large rising rate, and are rate sensitive to air temperature. Go down a wash-board road at a good clip and the pressure that you started out with isn't going to be the pressure that you finish with just due to the heating of the air in the spring. Maybe the delta is large enough to matter and maybe not. Depends on the design or the whole suspension and the loading.

Large rising rates are difficult to damp well. VW rear torsion bar suspensions (t-bars also have large rising rates) are notoriously difficult to damp well in a desert racing application. Controlling the rebound in particular. There are some methods known to work, but a low dollar twin-tube shock is hopelessly out-matched. It's not until you get to a remote reservoir damper that you have a chance, and even then you'll have to seriously customize them to make them work.

The only advantage that I see in a slipper arrangement is that the spring rate is not altered by where the shackle is in it's travel curve. Have a utility trailer built that way using '48 Ford F-1 front springs and it works well, but not a fan.

I keep hearing about these "parabolic springs" but I don't see any difference between they and a 'normal' leaf spring.

 

[greentruck]

I can't find the specific link right now where the Dexter axle was laid out with various suspension options pictured next to it. I may actually have been remembering seeing the Dexter TorFlex torsion bar option, but could've been the slipper springs. Who knows when you're out wandering the internet sometimes...

Did find a useful little manual summarizing the different features of the suspensions that Dexter offers that could be useful: http://www.dexteraxle.com/i/u/6149609/f/600-8K_Service_Manual/Suspensions.pdf

Looking through the rest of the Dexter stuff again, I suspect the reason the longest leaf springs they offer are 26" because they often are trying to squeeze trailer axles closely together, not a factor for a single axle design.

 

[LandCruiserPhil]

Lots of suspension choices all with pro and cons depending on application and needs. Looking forward to what LFD ends up with, why, and how it works in the end. If shocks are in the picture I would recommend an adjustable like a RS9000 or the likes.

LFD - Are you working and designing with a final running sprung weight estimate?

 

[LFD2037]

Lots of suspension choices all with pro and cons depending on application and needs. Looking forward to what LFD ends up with, why, and how it works in the end. If shocks are in the picture I would recommend an adjustable like a RS9000 or the likes.

LFD - Are you working and designing with a final running sprung weight estimate?

My trailer will weigh ~550-625lbs sprung weight NOT including loaded H2O tank ( ~170lbs.), fuel ( 60lbs.) propane (20-40lbs.) or any cargo w/possible RTT. I have 2 2'Tx2'Dx4'W plastic job-boxes that have all my 'hard' camping equipt. in them, not including any bedding, pillows, clothes, etc. & they weigh ~150lb. each.
550+170+60+30+300= 1,110lbs.
Throw in food, bikes, full cooler of adult beverages, toys, chairs, RTT, firewood, misc.= ~375
I'm guessing a weight of roughly 1,500lbs +/- 200lbs. for a max total of 1,700lbs. on the way to camp for 4+ days. On the way home I'd be ~400lbs lighter.
Probably figuring a little heavier than actuality but I'd rather build it for more weight than not enough. That's why I'm wanting 1K (each) rated springs. W/shocks it should ride good enough.
Sound about right????

 

[LFD2037]

Ordered a Dexter 3,500lb 64" hub face axle today. Been thinking about which coupler I'm going to use. I REALLY don't want to spend $250 on a multi-axis one & REALLY don't want to deal w/banging/clanging/rattling of a pintle. I've read a bunch today & some say, if trailer is loaded correctly, a pintle is matched properly then it doesn't make much noise. I can't handle a bunch of banging. How do I match the hook & the ring to where they're quiet?

 

[titanpat57]

I love the Bulldog, which i use use on my all purpose flat bed trailer, but I run a Max Coupler on the ROAM.

Don't forget...tongue weight is your friend.

 

[TRAIL TAILOR]

This is key. A back loaded trailer is a nightmare. I had a 22gal fresh water tank on my first trailer. We went out on a trip and I honestly forgot the trailer was on running down the highway. Turned off and went down the BLM road and still really quiet. I was impressed... Camped for 2 days, on the way back home trailer rattled, banged and popped all the way down the BLM road... I stopped and checked everything two times on the way out to the highway.. For the life of me I couldn't figure out what the issue was. Got home and finally figured out that we had used around 20 gal of water which was approx 170#s of mid/front weight missing.

I have tried to wrap the lower pintle jaw with bicycle tubes, nylon wrap and a few other snake oil remedies.... none are worth a crap IMO.

The trailer I am building now uses a 2" combo pintle with a 2.5" ID lunette ring. Same as my old set-up.

J

 

[greentruck]

There a little bit of clang every once in awhile with our M101 CDN with the standard lunette on a Reese combo pintle/ball hitch. I had the same concerns about too much noise, but there really isn't. And after that, the pluses far outweigh the intermittent clanks. The pintle/lunette is robust, cheap, and reliable, as well as offering excellent articulation.

 

[LandCruiserPhil]

 

[greentruck]

Another thought on minimizing pintle clang...a braked axle on the trailer should help to further limit this as it takes more of the slack out of the system that causes this.

 

[ntsqd]

From what I've seen minimum gap around the lunette thru the opening in the pintle is key to keeping the noise down. Built a tow bar to flat tow my '84 Xcab that uses the rotating lunette assembly that I built. Rarely heard it make noise in the two times that I've used it. No real tongue weight possible there.

 

[LFD2037]

View attachment 1107184

What's that called???

 

[LandCruiserPhil]

What's that called???

An improvement on the Pintle Hook is Vehicle Components VC COUPLING which represents a major breakthrough in the performance of ring type couplings. The key to its ingenious design is separating the ball movement from the clamp.

The coupling locks a conventional ring into place so there is no play in-between the towing vehicle and the trailer. The base of the coupling incorporates a sealed ball joint which provides the articulation between the two vehicles.

As the movement is fully sealed the coupling can be used in arduous conditions needing no maintenance. It does not experience the excessive wear that a pintle hook and ring gets in such conditions.

The lack of play in the coupling eliminates noise and damage between the vehicle and trailer and does not snag when reversing around tight situations.

 

[greentruck]

Couldn't find that one in a quick look-see, Phil, but maybe it's this one?
http://www.vehiclecomponents.com.au/hitches-couplings/hitchmaster-do65-trailer-coupling-1

Note that the lunette shown with this seems to be optional, as I interpret the accompanying text. Don't need no stinkin' lunette -- already got one

Looks like good stuff, much preferable to any of the multiaxis-SwissArmyKnife couplers. Not cheap, but within reason and certainly a nice-straightforward solution. Definitely on the someday-I-want-one list.