Trailer MPG and tendency to flip

[cstamm81]

Two quick separate questions here: How much does towing say an M416 trailer with a RTT mounted on it and loaded with camping goodies kill MPG? I would assume it can't be much worse than having the RTT on the roof, but I'm not sure. Just trying to stay out of single digits with my 80 series.
Also, my plan would be to have a rack on the trailer that would hold two kayaks below my Maggiolina. So, how easy are these things to roll over? I'd hate to flop it over with my Maggi on top. Thanks in advance.

 

[Martyn]

Two quick separate questions here: How much does towing say an M416 trailer with a RTT mounted on it and loaded with camping goodies kill MPG? I would assume it can't be much worse than having the RTT on the roof, but I'm not sure. Just trying to stay out of single digits with my 80 series.
Also, my plan would be to have a rack on the trailer that would hold two kayaks below my Maggiolina. So, how easy are these things to roll over? I'd hate to flop it over with my Maggi on top. Thanks in advance.

Our estimations on towing a trailer are that they reduce the mileage by around 10% -12%

If you raise the RTT up 12 - 18 inches to accommodate kayaks underneath it will raise your center of mass considerably. This will in turn increase the risk that the trailer will roll. The issue with the 416 is the springs are very stiff so they come down hard from any drop off and the suspension does little to dampen the movement. Most roll over occur after a hard landing followed by the trailer bouncing back upward and over.

You may do better to build a rack over the tent for the kayaks, or to use pipe insulation as padding and strap the kayaks to the top of the tent. Many people do the latter.

 

[MaddBaggins]

I ran a 4 day offroad trip last November with my new trailer and my 80. I used 31 gallons of fuel for 220 miles (thats 7mpg). It was 99% offroad and mostly in 4-lo. My rig is on 315's muds and 4.88 gears, 20 psi tires on the rig and 8psi on the trailer.
I was getting between 11-13 mpg on the freeway at 42psi rig and trailer between 60-70 mph.

 

[Martyn]

I ran a 4 day offroad trip last November with my new trailer and my 80. I used 31 gallons of fuel for 220 miles (thats 7mpg). It was 99% offroad and mostly in 4-lo. My rig is on 315's muds and 4.88 gears, 20 psi tires on the rig and 8psi on the trailer.
I was getting between 11-13 mpg on the freeway at 42psi rig and trailer between 60-70 mph.

Alvin

How does that fuel consumption compare when not towing over similar terrain?

 

[cstamm81]

Thanks for chiming in Martyn, and thanks for the numbers MaddBaggins.
Martyn, both of my kayaks weigh 60 lbs each. My RTT weighs about 125 (Magg Airland Med.) So, I'm guessing it wouldn't make any difference which one was on top. The thought of putting the kayaks underneath the RTT was so that the RTT could be cranked up without touching the kayaks. I'm guessing running this setup with your suspension conversion might make it more feasible? Or do you still feel the roll over risk would be too great?

 

[UK4X4]

With my D2, I found my trailer made very little diference to milage
its a high brick shaped vehicle on 33's which leaves a huge hole in the air behind....comfortably space for the trailer.

My old roof rack made more of a diference than the trailer does

Being that the D2 does scary milage anyway...I've never bothered counting....probably similar to a LC80

 

[Martyn]

Thanks for chiming in Martyn, and thanks for the numbers MaddBaggins.
Martyn, both of my kayaks weigh 60 lbs each. My RTT weighs about 125 (Magg Airland Med.) So, I'm guessing it wouldn't make any difference which one was on top. The thought of putting the kayaks underneath the RTT was so that the RTT could be cranked up without touching the kayaks. I'm guessing running this setup with your suspension conversion might make it more feasible? Or do you still feel the roll over risk would be too great?

Difficult question to answer. We had a thread about finding the center of mass of a vehicle earlier this month. It would be easy to do on the trailer and very simple as you would only really be interested in the tip over point side to side.

What I have witnessed is that most roll overs don't occur where you would think they would. All the ones I've seen of military trailers have occurred on flat-ish terrain where one tire has hit an obstacle and the trailer went up over it OK, then came down hard, and bounced back up and tipped over.

While our suspension would provide a much smoother ride over all and the Rancho 9000 shock should absorb most of the rebound there are no guarantees.

Your options are to soften the suspension you have on the trailer by removing leaves. Add a really good shock absorber. The RS9000 is great because it's adjustable to 9 different settings. Or replacing the leaf springs with a new softer set and adding the shock.

Either way you could build a rack that allowed you to put the kayaks under the tent and came out in front and behind the tent acting as a double roll bar for protection.

 

[Martyn]

With my D2, I found my trailer made very little diference to milage
its a high brick shaped vehicle on 33's which leaves a huge hole in the air behind....comfortably space for the trailer.

My old roof rack made more of a diference than the trailer does

Being that the D2 does scary milage anyway...I've never bothered counting....probably similar to a LC80

The trailers fall into the slip stream of the tow vehicle (aka Brick) with most SUV's, so instead of acting as drag in the same way a roof rack does it would seem that they mainly become a burden due to weight.

If my assumption is correct the main way to avoid major reduction in mileage would be to be conservative in slowing down and pulling away. Once the tow vehicle and trailer were up to speed the reduction in fuel consumption would be minimal.

Please poke holes in this theory as I need input for a project I'm doing.

 

[DaveM]

Two quick separate questions here: How much does towing say an M416 trailer with a RTT mounted on it and loaded with camping goodies kill MPG? I would assume it can't be much worse than having the RTT on the roof, but I'm not sure. Just trying to stay out of single digits with my 80 series.
Also, my plan would be to have a rack on the trailer that would hold two kayaks below my Maggiolina. So, how easy are these things to roll over? I'd hate to flop it over with my Maggi on top. Thanks in advance.

If it is not already equipped with a pintle hitch that would be one way to help insure your trailer stays bottom side down off road.

 

[MaddBaggins]

Alvin

How does that fuel consumption compare when not towing over similar terrain?

I would get 14-16mpg on the freeway. I never kept track offroad.

 

[elcoyote]

A quick question here: How long are the kayaks?

If they are equal in length or longer than the trailer, you will have a problem when you go through dips i.e. poking out the back window of your rig.

Conversely, if your kayaks are on the roof of your vehicle and hang off beyond the bumper, you may have similar problems. Take a careful look at the angles before you damage a window or a fine boat.

 

[Martyn]

If it is not already equipped with a pintle hook that would be one way to help insure your trailer stays bottom side down off road.

Many military trailer are fitted with rotational lunette eyes, so bottom up could still be a feature. If you fit a fixed lunette eye it decreases the stability of the trailer at freeway speeds and binds at around 30’, so in effect it doubles the movement of a ball coupler.

Although having a trailer roll isn't a great experience, what we have witnessed first hand is that in some cases the trailer has rolled and saved the tow vehicle from rolling.

Rolling a trailer isn't that common an experience, although it does take up the lion share of the campfire banter, and a fair amount of forum space. More than anything it makes for a good story and photo op. Miles and miles of towing the trailer over dirt and rock right side up isn't that spectacular.

I'll add one small story to expand the forum coverage.

One un-named employee of Rubicon Express did manage to roll a trailer on to it's side coming up Cadillac Hill on the Rubicon. He didn't realize the trailer was on it's side and dragged it up the rest of the hill. People at the top were whistling and shouting. The driver thought it was people expressing their appreciation of his driving skills!

The trailer suffered minor scuffing of a side box.

 

[DaveM]

Many military trailer are fitted with rotational lunette eyes, so bottom up could still be a feature. If you fit a fixed lunette eye it decreases the stability of the trailer at freeway speeds and binds at around 30’, so in effect it doubles the movement of a ball coupler.

Although having a trailer roll isn't a great experience, what we have witnessed first hand is that in some cases the trailer has rolled and saved the tow vehicle from rolling.

Rolling a trailer isn't that common an experience, although it does take up the lion share of the campfire banter, and a fair amount of forum space. More than anything it makes for a good story and photo op. Miles and miles of towing the trailer over dirt and rock right side up isn't that spectacular.

I'll add one small story to expand the forum coverage.

One un-named employee of Rubicon Express did manage to roll a trailer on to it's side coming up Cadillac Hill on the Rubicon. He didn't realize the trailer was on it's side and dragged it up the rest of the hill. People at the top were whistling and shouting. The driver thought it was people expressing their appreciation of his driving skills!

The trailer suffered minor scuffing of a side box.

I did indeed mean the fixed type of course

While I will admit to not knowing that much about pintle hitches I do know that we always used them on our farm/horse trailers at speeds up around 65mph in Hawaii no problem. They make a lot of noise as the hook and ring bang around but no instability. I suppose the real question is are you worried about tipping the trailer at high speed on the highway or by jostling it over off road. I would think the pintle to be preferred for stability off road but I don't have first hand experience beyond our small farm.

 

[MoGas]

I get ~10-11 MPG on the road weather I'm towing the M416 (loaded) or the boat.