Trucks & Trailers - Adjusting trailer weight after changing tow vehicle

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Joe
02-25-2011, 06:30 AM
I recently got a different tow vehicle. I went from a 2010 Toyota Tacoma 4x2 to a 2007 GMC Yukon 4x2. My boat, motor, and trailer weigh 5200#, verified at a local truck stop. Also from the truck scale the tongue weight is 460#, or about 8.8% of the trailer weight.

Towing the boat with the truck, the boat was stable and did not bounce around much at all. I attribute this to rigid the leaf spring suspension of the truck. It strained the truck to tow at highway speeds or over bridges (but that is another issue that has more to do with the with truck than the trailer set up).

I towed my boat on the interstate this morning for the first time with my Yukon...and it was a scary experience. Going over bumps and dips in the road at 50-60 mph sent the trailer into a violent up and down motion at the hitch; I could see and feel it pulling the rear of the Yukon up and down. I pulled over just to make sure the trailer hitch wasn't coming unattached! I've never had anything like this on any other vehicle tow comination, or with this combination towing with the tacoma. There was no trailer sway at all. Nothing has changed on the trailer weight or layout.

I'm thinking I may have too much tongue weight, but I wanted to get everyone elses thoughts. Do I need more tongue weight, or less? Or something else? The Yukon does not have any ride leveling shocks or anything like that...just standard coil springs and shocks. It does not overly sag when I load the trailer on it, and it drops maybe an inch or 2. And aside from the violent bouncing, it seems to pull it ok.


JALICHTY
02-25-2011, 06:37 AM
I'm not a mechanic and don't really know much about suspension, but I would suspect your shocks are shot based on my own experience. Had a truck that started bouncing more and more after going over bumps and turned out to be the shocks. Put on new Bilstens and no more bounce. Might look over the shocks before doing anything about the hitch weight.

Joe
02-25-2011, 06:51 AM
They are Bilsteins...Yukon has 36k miles. I would hope they would last longer than that.


DoubleO7
02-25-2011, 06:57 AM
Sounds like shocks to me as well.
They might be strong enough to control the action when Yukon is empty/light.
But not strong enough to control the action of the extra weight.

If yes, the same should happen if you loaded 460lbs of sand bags just inside the rear doors.

Going from a Tacoma to a Yukon, there also is different aerodynamics going on.

gf
02-25-2011, 06:57 AM
I think that tongue weight sounds a bit high for a Tahoe. Boats are typically at 5-7%.

Is the trailer absolutely level when on the hitch? If not, get a different draw bar to make it level. If that doesn't solve it, I would slide the boat back about 2-4" on the trailer to ease up the tongue weight a bit.

rwidman
02-25-2011, 07:09 AM
I think that tongue weight sounds a bit high for a Tahoe. Boats are typically at 5-7%.

Is the trailer absolutely level when on the hitch? If not, get a different draw bar to make it level. If that doesn't solve it, I would slide the boat back about 2-4" on the trailer to ease up the tongue weight a bit.

That's good advice. If the trailer is not set up properly, changing things on the tow vehicle is not the solution.

Is that load within the Yukon's tow rating?

fish factory
02-25-2011, 07:18 AM
(IMO) Keep plenty of weight on tongue, helps trailer pull straight.
And get some air bags for back of SUV. Cheap fix.

ryan g
02-25-2011, 07:48 AM
The yukon has the power and suspension to tow that boat. The other guys are right, take some weight off the truck and add it to the trailer (by sliding the boat ******. This way, when u go over bumps the truck suspension doesn't have to carry the boats weight.

I had a simular experience. Hit a bump on a bridge and the boat did come off the ball. I looked behind me and the entire boat was swaying back and forth being jerked by the safety chains. I stoped on the bridge, picked up the trailer and put it back on the ball (never been able to lift it before). And rode 2mph all the way home.
I redid my entire trailer from boat setup to the coupler the next day.

Joe
02-25-2011, 08:12 AM
I think that tongue weight sounds a bit high for a Tahoe. Boats are typically at 5-7%.

Is the trailer absolutely level when on the hitch? If not, get a different draw bar to make it level. If that doesn't solve it, I would slide the boat back about 2-4" on the trailer to ease up the tongue weight a bit.

trailer is pretty level. Seems I measured it once and the tongue is within 1-3" of what is at the tires.

The tongue weight, according to the owners manual, should be no more than 600# for a weight carrying hitch, or no more than 1000# for a weight distributing hitch.

My thought also is too much tongue weight. Odd that it trailered fine on the much smaller tacoma, but not so much on the Yukon.

RCook
02-25-2011, 09:06 AM
Be careful reducing tongue weight. My experience is that 8-10% is more the correct range for safety. Too little and you may have dangerous trailer sway. Take it to a truck scale and find out what the situation is before messing with it.

I'd guess you need new or beefier shocks.

rwidman
02-25-2011, 09:10 AM
OK, you've been told to reduce the tongue weight and you've been told to increase the tongue weight. Aren't you glad you asked the question? ;)

DoubleO7
02-25-2011, 09:12 AM
A beefier suspension will only reduce how much the suspension moves up and down.
Only sufficient shocks will reduce the amount of up and down re-bounding that takes place.

KarlP
02-25-2011, 09:13 AM
Try moving the axle forward or the boat backwards 4" on the trailer and remeasure the tongue weight. You probably do want it ~100lbs lighter. Boat trailer target is usually 5-7% tongue weight.

Short or long wheelbase Tacoma/Yukon? I'm thinking that if you had the long wheelbase Tacoma (141") and got the short wheelbase Yukon (116") you might be getting more pivoting between front and rear axles on the Yukon than you did with the Tacoma.

fish factory
02-25-2011, 09:29 AM
I towed my boat on the interstate this morning for the first time with my Yukon...and it was a scary experience. Going over bumps and dips in the road at 50-60 mph sent the trailer into a violent up and down motion at the hitch; I could see and feel it pulling the rear of the Yukon up and down.
.

A beefier suspension will only reduce how much the suspension moves up and down.
Only sufficient shocks will reduce the amount of up and down re-bounding that takes place.

;?

TSA
02-25-2011, 09:41 AM
needs more weight tongue weight.

move the winch assy 2 inches forward. tighten up winch strap and drive over a bumpy stretch of road. repeat and retighten winch strap until bow contacts bow stop. should solve problem.

agree that shocks should still be good but have them checked anyway.

KarlP
02-25-2011, 09:49 AM
OP - What brand trailer do you have? What does that brand trailer say is the target tongue weight?

Most of the replies seem to be leaning towards more tongue weight. It has been my experience that with too much tongue weight on some boat trailers, the trailer beams flex and spring with every bounce leading to more violent bouncing at the coupler. I haven't experienced this with steel box beam trailers, but have seen/felt this occur with aluminum I beam trailers and 10% tongue weight. If you get the center of gravity closer to the axle, there is less flex in the frame between the axle and coupler and the bouncing is MUCH less violent.

Joe
02-25-2011, 11:16 AM
OK, you've been told to reduce the tongue weight and you've been told to increase the tongue weight. Aren't you glad you asked the question? ;)

I sort of expected it I guess :)

Certainly others have towed a 5200# boat with a Yukon before and not had this problem, and I doubt the shocks are bad at only 36k miles.I've actually looked at them, and they look to be ok (no leaking oil) and they certainly ride okay. I recently got new tires (<1000 miles ago) and an alignment and noone said anything about needing shocks.

As for the Tacoma, it was the short wheel base but was a double cab. The Yukon is the 'short' version.

Someone else asked about putting the boat on the scale to verify the weight...that has already been done.

As for the trailer, it is a Road King aluminum dual axle trailer with tandem torsion axles and brakes on both axles. The axles can't be moved; but the winch stand/bow stop roller can be. I can move it back..but much further back and the transom won't be entirely supported by the bunks. I could not find anything on Road Kings website suggesting tongue weight specs. I did find an article written by a Road King exec that recommends 3-7% tongue weight.

DoubleO7
02-25-2011, 12:54 PM
Tandem torsion axles trailers must be pulled level.
In order to properly distribute the load per trailer axle.
I doubt that is the problem but maybe.
I tow almost the same weight with a first gen Tahoe 2wd.
Tongue weight has to be under 200lbs and pulls stable at all speeds Tahoe capable.
I know that I can fully retract the tongue jack and the tongue will not go to the ground.
Never have weighed any of it.

Throw 500lbs in the back end of the Yukon and go repeat your route and see what happens.
That will confirm the culprit as the trailer or the Yukon.

Keep in mind those Bilsteins are gas charged which could have leaked out leaving only the oil inside.

JALICHTY
02-25-2011, 01:30 PM
The Bilsteins are supposed to have a lifetime warranty, aren't they? At least that's what the deal said when I purchased mine about 60,000 miles ago. I don't know how you would check to see if they are working properly or not, maybe get on the back bumper and jump up and down and see what happens, as long as you don't miss and hit the ground, be careful. I know when I suspected my old ones were going bad, I just got in the back of the pickup and jumped up and down. With my considerable bulk, that pretty much cinched it that the shocks were bad.

dreamin-on
02-25-2011, 03:25 PM
I have the same trailer as you and had the same issue you are having. A Road King dual axle leaf spring trailer pulling a boat/trailer that weighs 4800 on the scale and 450# of weight on the tongue. Pulling it with a 2010 F-150 FX4. I feel your pain.

Exactly as you stated, when I had it on stretches of concrete interstate expansion joints the trailer was causing the back of my truck to porpoise badly. Most of the issue was boat placement on the trailer and the weight of the outboard bouncing up and down causing the bow to bounce. The cure ended up being the winch stand was a little too high, dropping it down 3 inches dropped the bow on the trailer and allowed it to settle into the bunks. It seems that I was winching the boat up off the forward bunks. Couple of other things that ended up making it rock solid:

-Moved the winch forward 2 inches bringing the tongue weight up to 450.
-Raised the hitch height by flipping the draw bar over. (Surge brakes were pulsing every time I went over a bump)
-Ran another strap from the bow eye to the trailer
-put a 2X4 under the motor (redneck transom saver)

Rock solid now. Maybe your suspension is a little softer than the Tundra?? Make sure that boat is strapped down into the trailer tight, makes a huge difference on a leaf spring suspension. Hope this helps.

Edit: Sorry, just noticed you had a torsion suspension. My opinion is that the the suspension on the Yukon is softer causing your problem. Maybe try a heavy duty version of the Bilsteins? I had a Pathfinder that did the same thing and stiffer shocks with air bags fixed it temporarily, removed the airbags and got a WD hitch for the SUV. Sorry for the rambling.

ReelWork
02-25-2011, 03:51 PM
It's not your shocks... It's the trailer and vehicle setup!

Move the boat back about 4-6 inches and see how that feels. (i.e. the winch post/bump stop)

Also, be sure the trailer is level... You want it to bounce straight up and down and that will only happen when level. Might mean you have to purchase a new receiver/ball with a different drop.

rwidman
02-25-2011, 04:32 PM
I sort of expected it I guess :)

Certainly others have towed a 5200# boat with a Yukon before and not had this problem, and I doubt the shocks are bad at only 36k miles.I've actually looked at them, and they look to be ok (no leaking oil) and they certainly ride okay. I recently got new tires (<1000 miles ago) and an alignment and noone said anything about needing shocks.

As for the Tacoma, it was the short wheel base but was a double cab. The Yukon is the 'short' version.

Someone else asked about putting the boat on the scale to verify the weight...that has already been done.

As for the trailer, it is a Road King aluminum dual axle trailer with tandem torsion axles and brakes on both axles. The axles can't be moved; but the winch stand/bow stop roller can be. I can move it back..but much further back and the transom won't be entirely supported by the bunks. I could not find anything on Road Kings website suggesting tongue weight specs. I did find an article written by a Road King exec that recommends 3-7% tongue weight.

I would try about 5%-6% tongue weight with a tandem axle trailer. See if that helps. Your short wheelbase may be part of the problem. Why can't the axles be moved?

Joe
02-26-2011, 07:58 PM
I would try about 5%-6% tongue weight with a tandem axle trailer. See if that helps. Your short wheelbase may be part of the problem. Why can't the axles be moved?

They are bolted to the frame of the trailer.

Joe
02-26-2011, 08:01 PM
It's not your shocks... It's the trailer and vehicle setup!

Move the boat back about 4-6 inches and see how that feels. (i.e. the winch post/bump stop)

Also, be sure the trailer is level... You want it to bounce straight up and down and that will only happen when level. Might mean you have to purchase a new receiver/ball with a different drop.


I think I agree with this.

I hope to go out in the boat tomorrow, so when its off the trailer I'll move the winch stand back a few inches and report how that does.

Joe
02-27-2011, 05:56 PM
I moved the winch stand back about 3 inches today. Not sure I can tell much of a difference; I am still getting quite a bit of rocking coming back from the trailer when I go over dumps and dips.

Move it forward now?

fish factory
02-27-2011, 06:02 PM
I would put winch back where it pulled good and put some Air Bags
on rear springs to stiffen up rear suspension...if you do, be
sure to plumb bags seperate.

dreamin-on
02-27-2011, 09:37 PM
I have been down this road before. The outboard on your boat is like a big counterweight and is what is ultimately causing the issue. Every time you hit a bump it bounces and takes weight off the hitch. Anything you can do to minimize this effect will help solve the problem.

rwidman
02-28-2011, 07:31 AM
They are bolted to the frame of the trailer.

If that would solve your problem, you could drill new bolt holes. Mine were attached with U bolts so moving them was relatively simple.

Joe
02-28-2011, 03:50 PM
If that would solve your problem, you could drill new bolt holes. Mine were attached with U bolts so moving them was relatively simple.


I'm still not sure whether I need to shift weight forward or backward.

rwidman
02-28-2011, 03:55 PM
I'm still not sure whether I need to shift weight forward or backward.

For less tongue weight, move the axles forward. For more, move them towards the rear.

Joe
02-28-2011, 04:27 PM
For less tongue weight, move the axles forward. For more, move them towards the rear.


Yeah..I know that part. I took statics :)

I just don't know which direction will have the best outcome.

rwidman
02-28-2011, 05:24 PM
Yeah..I know that part. I took statics :)

I just don't know which direction will have the best outcome.

I would be looking for that 5% - 6% tongue weight that most manufacturers recommend for tandum axle boat trailers.

Joe
02-28-2011, 05:40 PM
I would be looking for that 5% - 6% tongue weight that most manufacturers recommend for tandum axle boat trailers.

Then I went the wrong way with the winch stand.

BACKTOTHESEA
03-01-2011, 05:51 AM
Step one, when the boat is loaded with typical load of fuel, gear, ice, etc, bring rig to a level parking lot and measure the height at the vehicle and just in front of the wheel carriage(or between the wheels on a tandem. The difference in height should be no more than 1”. 1-3” is wrong.
Step 2, 460# of tongue weight on a 5200# rig is a little on the high side, but is within the recommended range. Let your existing suspension help dictate if you are too high. Sounds like you were probably close to where you need to be as you mentioned 1 1/2 “ of suspension travel under load. Revisit this step after step 3.
Step 3, on a reasonably flat surface, chock the wheels and remove the trailer from the vehicle. Put blocks or jack stands under the frame immediately in front of the front wheel of the trailer. Retract the trailer jack until the weight of the trailer is on the stands or locks. Loosen the winch stand and position the stand assembly so that the stand roller is snug against the hull of the boat immediately above the bow eye. Use the winch to snug up the assembly to the boat then tighten all bolts firmly. Now jack trailer back up, remove blocks and attach to vehicle.
Now test. I suspect that removing the flex in the trailer will have cured the problem. If not, you can lighten up the tongue weight a little. You certainly do not need 10%+, so you do not need to go heavier.
If none of this helps, you have either a suspension issue (springs and/or shocks), or you have under rated tires or a combination of both. Step 3 cured my issue hauling a 9000# loaded rig with a ½ ton truck.

tedg
03-14-2011, 12:17 PM
It may be easier to just add 200# of weight to the tongue to try rathe then moving the boat. I also have determined the amount of gas in boat has a lot to do with weight distribution! Trailers have to be level with torsion axles.
Ted

Joe
03-14-2011, 01:05 PM
As an update, I have tried a couple things to solve the violent bouncing going over bumps.

First, I lowered the tongue weight some by moving the winch stand back about 3 inches. This didn't seem to help at all, and in just a short time I towed it, it seemed to make the bouncing more pronounced. This also moved about 2 -3" of transom off the back of the bunks, leaving some of the transom unsupported. This wasn't something I liked either, so I decided to move the boat forward.

So I moved the winch stand forward about 6-7 inches from where it was (net 3-4 inches). I also got a lower trailer ball mount that makes the height of the trailer at the front of the trailer tires and at the hitch within about a 1/2" of each other. With this set up, there is still some bouncing at the hitch going over bumps, but it doesn't feel as much as before--maybe 30-40% less. The only problem is now I have no idea what my tongue weight is. *I could probably figure it out just using measurements from what I had (I don't have a bathroom scale), but it would just be easier to take it back to the truck scales to re-weigh it and see. I'll update when I get this done.

In summary, for the short distances I trailer this boat, my 2wd Tacoma did it better. It wouldn't work well for towing long distances at highway speeds, but for the short, flat distances I tow, it did a better job than the Yukon does. Had someone told me that prior to purchasing the Yukon, I doubt I would have believed them.

yarcraft91
03-15-2011, 07:08 AM
I had the same problem with a new full size Chevy van bouncing up and down in the rear when towing. At 12,000 miles I replaced the factory "heavy duty shocks" with aftermarket heavy duty shocks (Midas) and the problem disappeared. In the next 10 years of towing, the problem never came back.

If the trailer towed well behind one truck and not behind another, much heavier truck, look for the problem to be in the truck!



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