Tow problem - MC jerking my truck around - help

Hi Everyone,

I am a newbie with boats. I have an 88 Mastercraft Prostar 190 with a Tandem axel trailer with surge brakes. I am towing it with an 04 Dodge Ram Quad Cab 1500 with the Hemi in it. My problem is while towing it down the freeway, it jerks around a lot. Feels like it is trying to pull the truck backwards. Not sure what the problem is. Can anyone give me some suggestions? Anyone else had a similar problem? Thanks!

I have the same problem, but it's one of those things that you never think about fixing until you're pulling the boat. Then, once you put it away, you forget about it again.

My boat actually pulled just fine when I had a Dodge pickup, but since I've started pulling it with my lifted F350, it's been jerking around just like you describe. I'm wondering if my drop hitch is too low, so I've been meaning to get one that's an inch shorter. Not sure if that will work, but it's all I can think of.

Is the bow of the boat rested securely on the front of the trailer roller (or on some trailers, they have box type looking stop)?

On my trailer I have the roller type rest and if I dont get the bow of the boat to rest properly on it the boat tends to dip up and dow when moving.

Make sure your hitch hookup is at the right height. If it's too low or too high, it will put the weight of the boat on the front or back wheels of the trailer instead of distributing the weight evenly on both axles on the tandem.

My buddy had this problem on his nautique. We changed out the hitch and it took care of it.

Does it jerk while you are driving or just when you stop and go?

If it's stop and go it could be that the surge breaks on the trailer are bad. Perhaps a bad master cylinder. There may not be enough pressure in the trailer break lines which is allowing the hitch to move forwards and backwards each time you stop and go.

The bow seems to be resting fine. The hitch height I think is ok. I'm not sure exactly what it is supposed to be at, but the trailer looks flat. Maybe I will try one an inch or so shorter. The truck isn't lifted, but stock they are pretty tall. It only jerks while I am driving. Usually on the freeway - don't notice is too much around town. It seems to do it even more the rougher the road is. It especially doesn't like the concrete slab freeways.

A general rule of thumb (I'm told) is the bottom of the ball should be about 18" high. I've always used this as a baseline.

Do you notice that you are hitting bumps at the time it does it? If so you are actually slowing the truck a little or causing the trailer to "surge" forward and engage the brakes. Mine jerks a little because the hole through the tow bar is just slightly bigger than the pin so it slips a little at take off and during stopping. I don't tow far so I don't worry much.

Eric

I agree with all of the above too. 17-19" is abouto average. You may be running on one set of tires instead of both axles.

Also, tongue weight. For a 3K lb boat, should be about 350 lbs tongue weight.

I've seen tandems really act wierd because it wasn't being towed so that both axles shared the weight. This affects tongue weight too.

Just something else to check ! !

Thanks everyone. Looks like I have a good start to figuring this out.

You better check your shackle bolts. A friend of mine had the same problem until the axel seperated from the frame while driving down the road.

Ideally, your trailer should be just BARELY nose down. Also, is the boat loaded with gear? If its got a ton of stuff in it, it should be above or just forward of the axle(s) to keep tounge weight correct.

I'm interested too.

Sounds like we have the same truck, but mine tows my Cal-Air on a tandem way better and smoother than my old truck did (3/4 Ton Suburban)

The 'Burban seemed to get bounced around a bit by the boat. This was very noticible going down steep hills and rough high way. The Dodge on the same roads is super smooth and I am using the same hitch height too.

Might want to consider, weight in boat front biased or rear biased. Too much dead rear weight may cause too little tongue weight.

Chris
Get the Grip you Deserve
www.wakejunky.com

Sean, What hitch height are you using? Do you have the 4X4? (I do, it is higher than the 2WD).
I just measured mine and it seems like it is too low. 15.5" to the bottom of the ball. I just picked up another with a smaller drop so now it is 17.5 to the bottom of the ball. I'll try it tomorrow afternoon to see if this helps. I hope it does, I'd hate to ruin a brand new truck by doing something stupid. Thanks!

Craig, I just checked mine. It's 18" to the bottom of the ball unloaded.

I know that the Ram sits down quite a bit more than my Suburban did. Hooking the boat up to the 3/4 ton 'Burban barely made sit down at all.

The Ram is a '04 QCSB 4x4 on 20"s with 3.92 gears.

Sounds like the trailer is swaying to me. Perhaps you need to have the wheels/tires looked at and balanced. Do you have the same tires on all 4 wheels. If you don't, I've heard it can cause your trailer to track wierd.

Maybe I missed it but no one seemed to mention bad shocks on the truck. If you have anywhere near 50K on your truck you are due for new shocks. If you want it to handle well the only shocks to get are the Bilsteins.

i dont know about your problem but i had a Ford f150 ext cab for many years pulling different boats with no problems...I now also own an 04 Dodge Ram 1500 quad cab with the hemi and i am pulling a boat quite a bit bigger and heavier then yours ,a 2000 Supra launch..I have no problems whatsoever pulling at low or high speeds...

Yeah, definitely check that your ball height is such that your trailer is level. I was running a bigger drop to get more driveway clearance and that caused my trailer to shove my F150 all OVER the place. Setting it to level made all the difference in the world and it tows much nicer. Other thing to check is tongue weight. Matt is spot on that you should be running about 350lbs(ish) for your rig weight.

Can anbody explain the tongue weight issue?

Without enough tongue weight the boat trailer will not track correctly.

It may be too heavy for your shocks/truck, or, it may be too light ( too much weight at the rear of the trailer ) and fish all over the place.

IIRC, tongue weight should be around 15% of the total boat/trailer weight.

Nope - 10%

Thanks Matt, I will have to check on my hitch this weekend. I think I remember seeing a number of 500. I have never had any problems towing, just curious to know if there is something I am doing wrong.

How do you check tongue weight?

You can set the jack on a large bath scale, or use a suspended farm scale.

I figure if I can barely lift it, it's around 200-250.

Pierce, you may have seen a max tongue weight on your hitch of 500 - depending on the class of the hitch.

Does this sound like what's happening?

http://powerboat.about.com/cs/trailersusing/a/trailering.htm

Trailering Rule #4: Tongue weight - the amount of weight the trailer's tongue is carrying - should be approximately 10% of the total weight of both boat and trailer. If the tongue weight is too high, the strain on the hitch, trailer tongue and towing vehicle’s suspension system will be excessive. Steering quickly gets tricky as the towing vehicle becomes out of balance.

Conversely, if the tongue weight is significantly less than 10%, the trailer will start to weave back and forth. In other words, the tail starts wagging the dog.

In most cases, tongue weight can be adjusted by moving the gear in your boat either forward or aft. After you have your gear in the right position, make sure it's going to stay there, by properly securing it in the boat.

Very weird, I raise the issue with my wife this morning only after towing last night. Now I come into work and check the board and I'm experiencing the exact problem. I towed with our old Jeep Grand Cherokee a few weeks ago and had the same problem, although I had never experienced anything like it until this year. Then, I towed with a newer Denali and the same thing. Maybe it's tongue weight, cause both times, the load has been light. I'm also concerned the tires are out of balance or something like that. I'm pretty sure the hitch height is good.
It could be the surge brakes as well. How do I check these? Who would check my surge brakes for me?
I appreciate the help in advance.

So,I towed the boat with my fiends truck today. His hitch height is about 18.5" to the bottom of the ball. Seemed to be ok. A little jerking, but nothing I would worry about. I am not really having a problem with it swaying back and forth, rather just the forward and back movement. I'll check the tonguew weight later. I'm gonna be out of town this weekend (of course), but I will update everyone if I find anything. I appreciate all the advice!

I gotta say again, I will bet you that the tounge is moving back and forth because the hitch set up you have is slipping around inside the reciever. Take the trailer off and grab the ball and push it around and I bet it moves. All of that is going to be amplified when you talk about a 2500# boat doing the pushing at 30 mph.

Eric

It sounds like your hitchheight was too low (base upon your experience with a friends truck.) With tandemaxle trailers maintaining a nearly level attitude is very important. The axles are linked so that if one is stressed it will transfer some of the stress to the other for balance. However in a nose down attitude you can create a cycling where the front axle is stressed but sudden change in attitude (bump in the road) will shift weight back, balancing the trailer. However, as the vehicle rebounds from the bump the trailer attitude shifts further nose down and cause the surge brakes to momentarily engage. This is why tandem axle box trailers only use electronic brakes, which of course willnotwork with boat trailers. Hope that helps.