Tow Report: 24' Motorboat--didn't work out.

usa591 · **Posted:** Mon Aug 22, 2011 12:26 am

Hi Losters,

So my brother borrowed my truck this weekend to tow this rig:

Didn't work out--getting up and going wasn't a problem, stopping was. He said it was just too squirrely on the freeway and pulled the plug on the plan after three exits. :grim:

We figure that boat was too far back:

The boat is a 24' Pursuit Denali that the manufacturer claims has a weight of 5,135lbs. There was probably 70 gallons of gasoline in it's fuel tank. He thinks the trailer weighs 3,000lbs, I think more like 1,500lbs. Trailer had surge breaks.

I have taken this configuration on the road several times with great success:

This boat and trailer combo weighs 3,985lbs, weighed at the DMV scales.

geordi · **Posted:** Mon Aug 22, 2011 1:06 am

Yea, the stupid-long tongue on that is what was killing you, and I'm sure the tongue weight wasn't adjustable either. According to my numbers, you were anywhere between 7200 lbs and 8700 lbs for that rig. Is the trailer aluminum or galvanized? Those pics make it look galvanized, which with the third axle weight and the running gear for the boat... You might just be close to 3000 for that beast.

Surge brakes are nice, electric brakes are better. There are combo electric / surge systems I have seen for boat trailers, completely sealed to protect against water entry. To tow that and stop it, you would need to have control of the braking force and have much more force on the trailer brakes than on the CRD, transferring the force backwards and stabilizing everything.

Or... A properly sized trailer that isn't designed for a 35' boat, so the tongue is a LOT shorter. Then load the boat slightly aft on the axles to reduce the tongue weight, which will reduce or eliminate the push when stopping. That second picture shows the problem - The rear axle on the CRD is too compressed. Draw an imaginary line along the frames of both trailer and CRD. They should be parallel to each other, and parallel to the ground. They aren't. The CRD is CLEARLY settled in the back, which means too much ball weight pushing down, lifting the front and making the steering more loose.

With that arrangement and changing nothing other than positioning... Pushing the boat back 2 feet or so (maybe less) might have lightened the tongue enough to even things out and cured the handling.

I had similar handling problems when dragging my Grand Cherokee around with my CRD using a tow bar. Very short tongue, but when stopping and turning at the same time (like on an offramp or around a corner) there would be a BAD push from the GC, almost throwing me out of control. The fix? I had been using a drop hitch at the time, putting the ball lower than the bumper and having a definite down-angle on the tow bar. I changed NOTHING ELSE other than replacing that with a straight ball mount, now the tow bar is almost straight horizontal. The problem is gone. The tow bar has zero tongue weight normally, but when stopping, that 3800 lbs of Grand Cherokee exerts up to 3800 lbs downward through that ball, or straight... Depending on the angle of the tow bar and hitch.

By having that stopping force pressing DOWN even slightly on the ball, it lifts the front wheels which causes them to react to the trailer's force input more than the input from the steering wheel. When the force is fully horizontal... That doesn't happen. Moral of the story? Positive tongue weight is good. Horizontal frames (not excessively loaded away from an axle) is better.

OldSkull · **Posted:** Mon Aug 22, 2011 8:55 am

Tel me I'm wrong...Do you still have the OEM 4 ply Goodyear under your KJ ? If I'm wright you are lucky nothing happen, those donuts have "butter" ply sidewall! With such a heavy load behind they could shift in auto destroy mode in the blink of an eye. :shock:

Put the music on and sing "You make me feel like dancing.." next time :ROTFL:

usa591 · **Posted:** Mon Aug 22, 2011 11:10 am

OldSkull wrote:

Tel me I'm wrong...Do you still have the OEM 4 ply Goodyear under your KJ ? If I'm wright you are lucky nothing happen, those donuts have "butter" ply sidewall! With such a heavy load behind they could shift in auto destroy mode in the blink of an eye.

Ummm...yes. But don't worry, I injected them with foam for a poor-man's "run flat" mod.

boilermaker2 · **Posted:** Mon Aug 22, 2011 3:25 pm

usa591 wrote:

Ummm...yes. But don't worry, I injected them with foam for a poor-man's "run flat" mod.

You're a lucky man. Make sure you have the garage let you see/feel/touch your tires when you finally replace them. You'll s :!:

t your pants when you see the risk you just took. I'm not big on going out and spending a ton of money on this Jeep. That said, those tires are useless and dangerous if not used exclusively for getting groceries on a sunny day.

Glad you, your brother and KJ came out of it OK.

B2

ATXKJ · **Posted:** Mon Aug 22, 2011 7:08 pm

I think you're really lucky to not crunch something..
there have been several folks that towed really heavy things
- you might want to reread those threads.

jinstall · **Posted:** Tue Aug 23, 2011 7:24 am

I have towed more than 6000lbs with mine and had no issues. Not sure what the issue was.

usa591 · **Posted:** Tue Aug 23, 2011 1:28 pm

I think the issue was the weight being so far back on the trailer. Better tounge weight distribution probably would have helped, too. And braking--he said he felt like he just didn't have enough stopping power. Electric brakes probably would have helped as well.

ac5501 · **Posted:** Tue Aug 23, 2011 5:03 pm

boilermaker2 wrote:

usa591 wrote:

That said, those tires are useless and dangerous if not used exclusively for getting groceries on a sunny day.

B2

Those tires did get good fuel economy (at least for me anyways). I got about 80,000 miles (about 95% highway) before I replaced mine with Cooper Discoverers. I lost a good 3-5 mpg average per tank when I switched tires. Was getting 33-35mpg on the hwy(summer blend) before switching with my best ever tank at 37.5mpg(GDE Tune btw). Now Im getting 29-31. Still not bad though. I will admit that some of the mileage drop can be attributed to a little faster driving and I think my thermostat needs to be replaced.

dkenny · **Posted:** Tue Aug 23, 2011 10:09 pm

I agree with geordi,,
are you running C,D or E load range tires..makes a difference.
you too heavy in tongue weight? forget the %..is the load level? jeep level?
why? put 1000lbs tongue on your jeep..I'll put 1500 on my truck..want to see which tow better?
I would bet my truck..what to bet which is easier to park the trailer? ?YES the jeep..
why think about 3 feet between the front and rear axles..
how does this make a difference..
think backing and turning and think about a semi..very short dist between steering and rear axles compared to trailer tires..
so why was this unstable..I think Geordi has it nailed...TOO MUCH TONGUE weight.

not the length from the ball to the first axle..I think that's BS..

-dkenny

GaryC · **Joined:** Mon Mar 14, 2011 12:59 pm **Posts:** 21

I hate to say it, but that's just way too much of a load for a jeep liberty. I have a 2006 Liberty CRD, it's the reason I joined this forum. I also have a 99 dodge 2500 diesel pickup. I pull my 5x8 utility trailer with a Honda ATV on it with the liberty, I also pull a yamaha waverunner with it, anything bigger gets the truck. After pulling the smaller trailers with mine I can honestly say I don't think I'd want to pull anything over 3000 lbs. or so with it, even though jeep says it can pull 5000. The wheelbase is just too short for comfort and the rear suspension too soft to maintain adequate control of a bigger trailer. With that trailer and boat combination you've got a trailer that's twice as long as the jeep, weighs twice as much, and has marginal braking. It's a recipe for trouble. The boat's not too far back on the trailer, it's got plenty of tongue weight as evidenced by the squat of the jeep. It's just too much of a load for a liberty.

As much as people want to turn these little jeeps into trucks, they're not. Calling a liberty a truck is about like the guys with the fancy riding lawn mowers that keep calling them tractors. The liberty is great for what it's supposed to do but if you want to pull something the size and weight of the boat in the first picture then you need to get a real truck that can handle it.

geordi · **Posted:** Wed Aug 24, 2011 1:39 am

Sorry, but that is a misinformed opinion. The wheelbase of the Liberty is just fine, provided that the trailer (any trailer) is PROPERLY LOADED. The "squat" of the Liberty that you mention is proof that it is NOT properly loaded. Using the argument that you need a longer wheelbase to tow is simply continuing the misconception and a basic misunderstanding of the physics involved. A longer wheelbase does not correct for improper tongue weight, it masks it.

For your CRD that you say has too soft of a suspension, what tires do you have? Have you tried some ACTUAL light-truck tires on it instead of the woefully-underrated stock Goodyear PASSENGER CAR tires they sell it with? You will probably be pleasantly shocked about how much better it handles while towing.

Think of the ball as the fulcrum of a big lever or see-saw. If a see-saw has equal length on both sides, it will balance perfectly horizontal. That is what you want. If one side has a 50 lb weight at the end, you need either a 50 lb on the other end, or 100 lb half way back to center... And it will again balance. If you have a 50 lb weight at the end again, but only have a weight just past the center point... That second weight might need to be 500 lbs to balance. See how putting the fulcrum further and further away from the weight means you need LESS weight?

Another way to think of it: If you have your weight (the truck engine) 25 feet away from the ball, (in all times, the rear wheels are your pivot point) then to lift the front wheels and destabilize the steering will take LOTS of weight because that lever is very long. The opposite side of that lever (from the rear wheels to the ball) is very short. Yes, trucks like an F350 can take stupid amounts of tongue weight and be "safe" for people that don't know how to load a trailer properly because all the weight is on the "short" side of the lever.

For a "short lever" like the Liberty, the answer is simple - REDUCE THE TONGUE WEIGHT. You are trying to PULL something, not LIFT it. The distance from the rear axle to the ball is roughly the same as on a truck, but yes, the longer side of the lever is much shorter than the truck. So if you put a stupid amount of tongue weight onto the Liberty, the frame will show you that it is improperly loaded by NOT being parallel to the ground while parked, and when you are driving and attempting to stop, the direction of force will push through the ball and BELOW the frame (pushing the ball down) and lifting the front wheels even more. This is what makes a tow "unsafe" and it all comes back to IMPROPER LOADING and too much tongue weight.

At all times, you want the forces to be parallel to the ground. When you pull, the force is straight through the ball from tractor to trailer. When you stop, the force SHOULD be the same, but as a "push" from trailer to tractor because of inertia. If the frames of both vehicles are not straight and parallel, you have a "vertical jackknife" attempting to happen.

By the way, talking about the length of the trailer in relation to the towing vehicle - Semi-trucks have been mentioned already, but they kinda don't apply b/c the weight and pivot is sitting directly on the rear axle. But have you ever seen a Mobile Home company making a delivery? That is a 60 foot long building being towed with a TRAILER BALL by a truck that has EXACTLY THE SAME WHEELBASE as our CRD. Why doesn't the tongue weight lift the front of those trucks? Believe it or not, but the tongue on something that big is actually only about 1500 lbs, and the trucks usually have a LOT of cement blocks on them. They tow safely all the time because they can correctly manage the tongue weight to keep the frames parallel.

Oh, and here's an example of a safe towing setup that I have done MANY times perfectly safe. Notice the rear wheels NOT sagging like with that boat b/c I have the right tires for the job. Stock suspension on my CRD.

onthehunt · **Posted:** Wed Aug 24, 2011 10:03 am

Quote:

But have you ever seen a Mobile Home company making a delivery? That is a 60 foot long building being towed with a TRAILER BALL by a truck that has EXACTLY THE SAME WHEELBASE as our CRD. Why doesn't the tongue weight lift the front of those trucks? Believe it or not, but the tongue on something that big is actually only about 1500 lbs, and the trucks usually have a LOT of cement blocks on them. They tow safely all the time because they can correctly manage the tongue weight to keep the frames parallel.

So what your saying is you could safely tow a 60 ft mobile home with your CRD by just managing the tongue weight???

They tow safely all the time because they know what they are doing and have a dedicated purpose-built tow vehicle to do it. It is that simple. CRD is about the furthest thing from that. The only thing they have in common is the fuel they burn.

geordi · **Posted:** Wed Aug 24, 2011 1:10 pm

Troll.

What you are claiming is that you can fly by flapping your arms b/c that is what birds do? You have it in common that you both exist in air...

The engine of the vehicle manages the weight of the trailer. The size of the vehicle physically and the location of the tow point in relation to the rear wheels manages the tongue weight.

Learn physics, please.

Can the CRD tow 1000 lbs? Easily. Can the CRD tow 1000 lbs loaded ONLY onto a receiver-tray, which would be equal to 1000 lb tongue weight? NO. That is not safe, just as 1000 lbs of tongue weight is not safe with a 35 foot trailer. It is the tongue weight only, causing the problem. The ultimate weight of the trailer is irrelevant in this example, the engine can easily handle the total weight.

papaindigo · **Posted:** Wed Aug 24, 2011 3:51 pm

Have to go with geordi on this one. IMHO towing involves 3 critical factors: 1) is the vehicle/engine combination adequate to pull the weight in the terrain and temperature conditions expected (remember in theory with proper gearing I could pull a freight train with a lawn mower but so what that's not an adequate combination); 2) can the vehicle stop the tow safely on its own or with supplimental brakes on the tow (keep in mind that brake quality and how well the brakes function, particularly on the tow, are critical; surge brakes are ok but on a boat trailer just having them doesn't mean they function; adjustable electric brakes are probably better); and 3) is the tow load balanced correctly front to back and with respect to the vehicle's hitch height. In this example the trailer is grossly over long for the boat and likely not balanced correctly. Looong years ago I towed a 12' aluminum boat with a 9hp kicker on a trailer sized for a 20' boat (the owner thought he would buy a big trailer because it would be stronger than a proper size trailer); it was great fun behind a Datsun pickup until we got boat/trailer position sorted out.

Bottom line #s 2 and 3 are absolutely critical to safe towing and handling. #1 is more a case of do you have enough umph to make the pull with adequate acceleration and speed maintenance; as such while important it's somewhat less so than the safety critical factors.

onthehunt · **Posted:** Wed Aug 24, 2011 4:44 pm

Geordi,I think your the troll here. Bragging about how you pull uber pounds and it's all good. What people fail to understand is your trailer setup is ideal. Short wheelbase,tandem axle, minute frontal area, and static weight that is loaded perfect on the trailer and never changes. You are the exception to the rule.

dkenny · **Posted:** Wed Aug 24, 2011 5:38 pm

onthehunt,
you missed the point..its not the frontal area..that would determine the max speed not the handling.

that OP's setup has too much tongue weight. or use a weight distributing hitch. that's what they're made for..to force the front the tow vehicle down..and level the load.

geordi brought towing mobile homes because of the hugh size and weight..but what's % tongue weight? 10%..don't think so..that would mean if the tongue load is 1500 lbs the total is only 15,000?? with tires that carry 3000 each and how many sets??

I still agree with geordi on this one..in fact I tow a trailer, about 4k, just about every day..but not with a Jeep..

I would rather have a longer distance between the ball and trailer tires and ball the front tire of tow vehicle..way easier to handle..don't believe me try backing a jet ski trailer with a long bed pickup..

-dkenny

GaryC · **Joined:** Mon Mar 14, 2011 12:59 pm **Posts:** 21

deleted

dkenny · **Posted:** Wed Aug 24, 2011 7:31 pm

yes the US spec for tow is 5k and 500lbs tongue..but why is the European spec for the same model 7k??

for tongue weights..no 15-20% is not better..unless the tow vehicle can carry the weight..and no 10% is not hard and fast..sorry..maybe for a single axle trailer not multi axle..the game changes. but yes if you run a negative tonuge weight..bad news..

just think about a mobile home 1500lbs tongue weight..that's 20% of the total..I don't think so..let's see 6 axles at 6K per axle?? is 36000 lbs..and 20% is 7200 lbs..not on any trailer ball made. I'm not sure a pintle hook will take that much load. mobile trailer tires are 14ply not 10ply.

-dkenny

jinstall · **Posted:** Wed Aug 24, 2011 8:32 pm

I can't beleive GaryC compared a KJ to a 3/4 ton truck, apples and oranges, of course they are different, they should be. Now if you had compared it to a Honda Pilot or a LR3 I would be more open to accept this comparison. 10-15% on a properly loaded surge brake trailer that is PROPERLY mainatained is your best bet on towing heavy loads with the KJ. I have done it many, many, many times on different terains. As for the boat issue at hand, I woulld like to see how the boat balances out on the scales before any final comments can be made. I have towed a Grady White from NC to FL in a SWB Dodge cargo van with 226 I6 and a 3spd floor shift with no issues at the young age of 15 on a restricted permit with not a single issue. I have towed all kinds of stuff for the US Army in my 22 years of service as well as probably a million miles in that time.

Tow Report: 24' Motorboat--didn't work out.

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