Test with simulated tongue weight - yikes! No wonder the RAKE

[wannajeep]

And if you towed a 5500 pound trailer, 500 under the max, you'd have another hundred pounds tongue weight. That would likely drop this at least another half inch.

For that sort of weight a weight distributing hitch would really be appropriate, and should level everything out.

You are supposed to be able to tow 6000 pounds - no way with these springs.

I can't imagine the Pentastar 3.6L V6 tugging 6,000 lb very well. I did around 3,500 lb on a JK and it was okay but not great. The spring problem can be solved with the WD hitch but horsepower and torque is what it is.

Don't get me wrong; I love this rig and will be towing with it.

Sponsored

 

[ShadowsPapa]

I figure that sooner or later, somebody with a Max Tow will install an aftermarket coil spring lift kit. When they do, buy their factory coils from them and pop those on your truck. Would be a great time to add some 3/4" poly spacers also for just a touch more space.

Then, you'll be able to put several hundred pounds of tongue weight on it and you'll be OK.

I'm glad you see that I am not wanting to HAUL over 6,000 pounds or have OVER 600 pounds tongue weight - I know it's not a max tow, but the amount of spring sag is crazy.

When they advertise 600 pound tongue weight and 6,000 pound towing, it should handle 450 pounds of weight and 5,000 pound tow. - well under their limits.
I would expect a fair drop if a person dropped a 6,000 pound trailer with a 600 pound tongue weight on it.

 

[ShadowsPapa]

For that sort of weight a weight distributing hitch would really be appropriate, and should level everything out.


I can't imagine the Pentastar 3.6L V6 tugging 6,000 lb very well. I did around 3,500 lb on a JK and it was okay but not great. The spring problem can be solved with the WD hitch but horsepower and torque is what it is.

Don't get me wrong; I love this rig and will be towing with it.

Sorry but maybe you missed my earlier comment -- you cannot use load-leveling/weight distribution hitches on ALUMINUM trailers. It's not allowed, it voids warranty, makers of aluminum trailers say "don't do it". I even spoke with a design engineer for one company a few months back. He was a real engineer with degrees, etc. and he laid out the forces, did the math, showed diagrams.

That's not much weight at all. I've towed heavier with no load leveling hitch. Most guys I know with 18' car haulers don't use such hitches anyway. Your tongue weight is well under the max. When we moved my son to his house years ago (he and his wife lived with us for a while) we loaded up his stuff on my then car hauler (a heavier, all-steel trailer) and hooked to my wife's Grand Cherokee - it may have dropped an inch or so. I was impressed. But then it's rated for 6200 pounds towing! Go figure.

My wife is now saying - when it warms up a few degrees, pull one of the cars out and take the trailer off the stands and hook up and try it - and if it won't handle it, you'll just have to trade"

As far as the 3.6 - my only concern is the gearing, This truck spends a lot of time in 6th and 7th gear around here on our highways.

 

[wannajeep]

Sorry but maybe you missed my earlier comment -- you cannot use load-leveling/weight distribution hitches on ALUMINUM trailers

Correct, hadn't seen that. Makes sense.

My wife is now saying - when it warms up a few degrees, pull one of the cars out and take the trailer off the stands and hook up and try it - and if it won't handle it, you'll just have to trade"

:D

 

[jurfie]

...and hooked to my wife's Grand Cherokee - it may have dropped an inch or so. I was impressed. But then it's rated for 6200 pounds towing! Go figure.

Try the exact same simulated tongue weight test on the GC and see if it sags more than it did with your car hauler. Just to compare (and hopefully save you from dragging the car out and hooking it up to the JT in the cold). It would be interesting to see if the test results in the same drop of "an inch or so" on the GC.

 

[AggieJeep]

Try the exact same simulated tongue weight test on the GC and see if it sags more than it did with your car hauler. Just to compare (and hopefully save you from dragging the car out and hooking it up to the JT in the cold). It would be interesting to see if the test results in the same drop of "an inch or so" on the GC.

‘This should be a helpful comparison without having to go all out with the car hauler. This is making me dust off some of my load analysis from engineering school. Don’t underestimate the effect of those last two blocks being another 9 inches or so back from the virtual ball. That leverage gain is not insignificant. 8 x 60lb blocks with two of them further back along with the weight of the carrier, I think your simulation is likely topping 500 and change.

‘Your towing needs may still require additional stiffening, but really, couldn’t we all benefit from that?

 

[12BNNT]

Without going into a long winded explanation of physics there is another option to try. Coil springs are ALL progressive to a degree. Some are just spiraled to be more variable. (Soft on the first couple inches of compression and tighter on the rest to give softer unladen ride but handle more weight loaded). Technically, if you put 400lbs tongue weight on the draw bar and it drops 4 inches that does not mean 300 will drop 3 and 600 will drop 6”. Lets say you and your buddy both weigh 200lbs. One person stands on the bumper, the bumper may drop 2&1/2 to 3” but when the second person gets on it will only drop another 1&1/2”. Add a third and it only drops another 1/2-1”. (These are rough example numbers)
So for the possible solution, as someone else pointed out, consider coil spacers. Ask anyone that has used coil spacers, it stiffens the ride especially if you put a in spacer without adding longer shocks or shock extenders. It will give a little more ride height but also (to some degree) precompresses the spring a bit. Now adding weight to the back doesn’t drop as much because the spring is already compressed past the softest part of the compression.
Prime example, I started out with a 2&1/2” spacer lift in my JK. Got 2&1/2” of lift and a stiffer ride. Pulling my box trailer my back bumper dropped xx”. Changed that out and put in 3” lift springs (no spacers). The coils in the springs were actually wound tighter than the stock springs but... I got a 1/2” gain in total height and a softer ride but hooking up the same trailer, same tongue weight and my back end squats lower than it did with the lower starting height using spacers.
So, putting in 1/2” or 1” spacers without any shock extenders may net you that little bit of ride height but will also give you less loaded compression being as it would be precompressing the springs by a small amount. That is if you’re willing to accept a slightly stiffer ride.
Not sure if that makes total sense putting it in laymen’s terms without doing all of the physics math, but hopefully it gives you a general idea.

 

[12BNNT]

Another idea would be air shocks that could be run on lower pressure for daily use but air up to higher pressure towing to help lift the rear of the truck.

 

[ShadowsPapa]

Thanks but I am a college trained tech and worked doing suspension and steering for years.
There are specifics about the JT construction and such I'm boning up on but springs I know having rebuilt countless suspension systems.
There is one thing you have said that doesn't compute - and has been shown to be otherwise even in this forum. More than one person here has posted about spacers under springs because it won't or should not (if done correctly) change the ride - because it's the same exact spring compressed in the exact same way under the exact same vehicle weight.
Assuming you are talking the spacers that go UNDER springs for a LIFT, that does not change the spring weight carrying capacity, length, rate, ride, etc. It simply lifts the spring up. So unless there are links or control arms out of sorts - meaning you have lifted and the links are at a more severe angle, it won't change the ride at all. That's been said here before. Lifting over a couple of inches without other changes like links or control arms will change the vehicle's personality because now those arms are angled down and there are different stresses on them. (especially if you did not loosen the TOP end, let the truck down then retighten them)
Take any car or Jeep or truck coil spring and put it on your bench. Assuming your work bench can handle the weight (mine are rated over a ton), put 1,000 pounds on top of that spring. Now measure from the bottom of the weight to the top of the bench.
Remove the weight, put two 2x6's stacked under the spring. That would be 3" thickness, like a 3" spacer or lift.
Put the weight back on the spring. Measure distance from bottom of weight to top of bench. It is now exactly 3" more. The distance from the weight to the top of the 2x6's will be exactly the same as it was before. (ok, physicists, I realize that in the real world because the weight is now 3" further from the center of the earth the pull of gravity will be less but I dare you to measure it LOL) Nothing about the spring has changed, not the rate, not the load, not the compression.
Spacers under the spring will not change the action of the spring at all. That's the beauty of that sort of lift. The ONLY way you would need shock extenders is if you exceed the travel of the shock in doing so, otherwise the valving and shock action won't change on a standard shock. All a shock does is dampen, it doesn't support. If you are moving the shock piston in the bottom 1/3 of travel and lift the vehicle and are now using the middle 1/3 it won't change a thing. The shock action will still be the same.
If spacers under a spring changed the ride - there were other factors at play because they were supporting the exact same sprung weight. Unless you added weight to the vehicle or changed shocks, or unless the control arms and links were NOT loosened at BOTH ends and then retorqued with the vehicle at the new height, nothing changed. When you change vehicle height or have pieces like control arms or links that are running a different angle to the vehicle, you need to loosen BOTH ends then set the vehicle on the ground at the new curb height and then torque the link and control arm bolts again. Failure to do so pre-loads any rubber bushings.
I can show this in my college book and other tech manuals. So if you put a lift kit in - say just use spacers under the springs, you are moving the axle further away from the truck - and the links and arms are now running at different angles. If you didn't loosen both ends of the links when the spacers were put in, then set the truck down and tighten them again, you have put a load on the bushings.
Control arm and link bolts where there are bushings, especially rubber bushings, must be tightened and torqued with the vehicle sitting on the ground, not with the axles dangling down with the truck on a lift or stands.

I also understand fully about how spring work as far as 400 pounds may drop a vehicle 4" but the next 100 pounds won't drop it another inch - I knew that. I've hauled tractors, antique engines , cars, etc. since the 1970s My concern was that with the weight I tested it dropped SO FAR - the back end sagged badly. It was not acceptable at that point - so adding another 200 pounds to the back would drop it even further - I never said another inch or 2 inches., just more than what it already dropped - which was unacceptable.

There is no way in heck I will put air shocks on a vehicle to help support it - now you are trying to support the vehicle by places that were never meant for such load. I've seen shock bolts broken, brackets bent and broken and worse. Air shocks are a total band-aid. I simply will not support that sort of a load through shocks. It's wrong. I know people do it and I'll get smacked by the "I do it all the time' crowd here but I've seen too much damage and I won't put air shocks on a truck to support the weight when springs are supposed to do that.
I only have them on my little Eagle to balance the car until I can get the correct springs under the front because the company that made the springs made them out of the wrong wire and way too stiff for the car - so the front of the car sits a good .5 to 1" too high (and as such as stressed the suspension) But those air shocks are coming off or at least being run minimum pressure once I get better springs under the front.

 

[12BNNT]

?????

 

[12BNNT]

Okay. I didn’t mean to belittle you by babbling on in laymen’s terms. No offense was intended. Was just trying to give you something to think about just as this thread caught my attention being something to think about myself when I can buy a either a max tow sport or overland JT next spring. So....

Let’s try to explain this a little different.

We are in agreement that springs compress in a way that (in just made up numbers) that 200 tongue weight might sink your bumper 2.5”. 300 sinks 3.5” and 400 is 4”.
Now a spring sitting on your bench or in a press with a pressure plate under it is going to compress X” with 1000 lbs of force regardless of whether you put a board under it, over it or no board at all. I completely agree BUT let’s take that same 24” spring, put a 2” board over or under and then bring the press head down to 24”. How much has the spring compressed (2”)and how much pressure is on the spring?
Now on the Jeep, car, truck, or whatever, if you disconnect the sway bar, lift the vehicle to the point where the axle is held up by the length of the shock, the spacing from lower perch to upper is roughly the length of the unladen spring (not further or people’s springs would be falling out when they flex the suspension off road) NOW, let’s stick a 2” spacer in there between the spring and perch. At full droop, no vehicle weight on the spring (With the shocks attached and no extender on it) that spring is compressed roughly 2”. Now when we set the vehicle on its tires putting the weight of the vehicle on the springs, being already compressed in the cavity by 2”, let’s call it 1000lbs of body weight only compressed the spring 5” instead of 6 because of the preload on the spring giving you 1” of lift. And a little stiffer ride.
As far as the air shocks.... I TOTALLY agree that you wouldn’t want to use them to support the 400 added by tongue weight. As you said, that would shear a bolt or blow the seals. My thought was more to the point of having damn near no air in them for daily driving just providing rebound control letting the springs hold the truck not the shocks. As it should be! But when loading the tongue weight on, you could add some air to them to take 60-70 pounds of air pressure to ASSIST the springs so the springs are holding 340 instead of 400 giving you back maybe 1” of ride height.
Anyway, I hope I was more clear and not so insulting this time. Really am just trying to help you come up with solutions not lecture anyone. You know this stuff well enough and are researching away, so I’m sure you’ll come up with a solution that meets your needs. I am going to continue watching this thread knowing what you come up with may help me or others down the road.

 

[WXman]

I have a storm water run-off issue on a part of my property so I need sand bags. Sounds like a great idea for a video, so tomorrow I'm going to start throwing sand bags in my truck until it hits maximum payload (1,511 lbs. in my case). I will take before and after measurements to see how far the Max Tow suspension will sag.

 

[RH 67]

I have a storm water run-off issue on a part of my property so I need sand bags. Sounds like a great idea for a video, so tomorrow I'm going to start throwing sand bags in my truck until it hits maximum payload (1,511 lbs. in my case). I will take before and after measurements to see how far the Max Tow suspension will sag.

Good general idea but it will not help the OP, as payload and hitch loading will give different results as for how much the rear will sag.

 

[eaglerugby04]

Good general idea but it will not help the OP, as payload and hitch loading will give different results as for how much the rear will sag.

Still will be really cool to see what the sag is like with payload in the bed and maybe at different parts, front, balanced and rear.

Doing a complete tongue weight test with these sand bags would also be pretty cool. I know when I loaded my trailer with a few trees I actual needed to re-adjust the height of the ball due to the amount of sag just to get the trailer across my yard

 

[PyrPatriot]

I have a storm water run-off issue on a part of my property so I need sand bags. Sounds like a great idea for a video, so tomorrow I'm going to start throwing sand bags in my truck until it hits maximum payload (1,511 lbs. in my case). I will take before and after measurements to see how far the Max Tow suspension will sag.

Maybe put in max payload minus your weight to show how it would be if you were driving?

Sponsored