10% TW to 13% TW...did not seem to make any difference

RinconVTR wrote:


The weight at the jack will always be a little MORE...yes MORE than the hitch/coupler.

That is exactly correct. I have the Sherline scale and their instructions clearly state "The most accurate measurement of tongue weight is achieved by measuring right where the hitch actually rests on the ball"
Then they state:
"Once you are familiar with your trailer, it will be easier to measure tongue weight at the tongue jack rather than at the hitch. Once you have determined the actual tongue weight at the hitch, we recommend you take a reading at the tongue jack itself."
Once you have determined what are TW at hitch and TW at Tongue Jack, then you use the following formula as per Sherline instructions:
"For the ultimate in accuracy, note the actual difference in weights and calculate the ratio by dividing the full hitch weight by the weight at the tongue jack.
Example:
Weight at hitch = 950 lb.
Weight at jack = 1000 lb.
950 ÷ 1000 = .95
Future measurements at the jack multiplied by .95 will yield the exact weight at the hitch itself."

RinconVTR wrote:

93Cobra2771 wrote:


I'm sure one of the engineering types in here could give us the percentage of error on measuring at tongue vs at the jack.

Guess now I'm the one nitpicking. LOL

I am, and after running quick estimates, I need to post a correction!!!

The weight at the jack will always be a little MORE...yes MORE than the hitch/coupler.

And we're talking differences of only (and roughly) 40-70lbs for trailers around 10k lbs. Give or take...there are so many variables.

If you have a scale, its good to know the difference between the jack and hitch, cause then you only need to check at the jack thereafter.

Thanks for confirming my suspicion that I was afraid of posting. I was thinking that it would actually be heavier at the jack than coupler, but was too chicken to post it. LOL. My reasoning being that the closer the scale to the wheels, the more weight it takes off the wheels.

I also suspected the amount of difference would be pretty minimal.

Carry on!

cruz-in wrote:
A64HD, thanks for input....I too am beginning to think that my setup, which only allows a max of 13% TW may be part of the problem....I guess problem amy be too strong a word...maybe issue is better as the trailer tows wonderful on decent mpavement.

As the TV needs them anyway, I am going to replace the shocks with Bilstiens. I expect a minor improvement but recognize that is not a silver bullet.

Hi Dan,

To add to the mystery, On my rig, I have 16% loaded TW. 1,600# on a 9,950# GVW TT using 1,700# WD bars. If I hit that perfect patch of concrete joint length, above 48mph, it will set the rig into an up and down motion that will stay constant until either the road changes or the speed goes lower. It acts like the natural frequency of the system just went off.

If you are experiencing what I do, going higher TW will not cure it by itself. And I'm on the Blisten 4600's now. The TT has Monroe Gas Magnum shocks and rubber equalizer and LT tires.

For me, the good news is, that stretch of road is ~ 3 to 4 miles long... And I only go over it once a year...The other 30,000 miles I have on this rig never had a problem.

Hopefully in all this, you can find a nuget that may help this. I myself would like to know it too. Backing off speed is the interim fix.

John

Lynnmor wrote:
To get back to the original issue, does the trailer and truck feel like they are rising and falling together. I would describe porpoising as a rocking motion and not the issue at hand. My combo appears to rise and fall together and not have a rocking motion on the type of roads mentioned previously.

I noticed that the issue actually got worse after adding shocks to the trailer. All other handling improved with shocks. I suspect that the shocks are not allowing the springs flex as much. A trailer with longer, weaker springs might not transfer as much energy to the truck.

Thanks for taking the time to respond...I will have to pay attention during the next tow to the motion to better describe it....there cerrtainly is some porpoising (rocking motion), however the most uncomfortable seeems to be abrupt raises and falls in the TV/TT combination.

That is interesting that the shocks made that one issue worse...I have seriously been considering shocks on the TT also...

A64HD, thanks for input....I too am beginning to think that my setup, which only allows a max of 13% TW may be part of the problem....I guess problem amy be too strong a word...maybe issue is better as the trailer tows wonderful on decent mpavement.

As the TV needs them anyway, I am going to replace the shocks with Bilstiens. I expect a minor improvement but recognize that is not a silver bullet.

RCMAN46... What part of the post you quoted above can you not understand. It tells how I weighted the traielr and the GVW.

RCMAN46 please stop responding .....PMs and postinngs on this thread clearly indicate others understood and are trying to be helpful..reviewing your previous posts shows picking on folks on rv.net is just sport to you...please stop responding to this thread...

cruz-in wrote:

As I wass very concerned about trailer sway (with this long and high trailer), the Hensley (or 3P) was very attractive...

If the trailer is properly loaded I have had better towing experiences with longer/heavier trailers.

A properly loaded trailer won't sway, but that may take more TW than you can right now.

To get back to the original issue, does the trailer and truck feel like they are rising and falling together. I would describe porpoising as a rocking motion and not the issue at hand. My combo appears to rise and fall together and not have a rocking motion on the type of roads mentioned previously.

I noticed that the issue actually got worse after adding shocks to the trailer. All other handling improved with shocks. I suspect that the shocks are not allowing the springs flex as much. A trailer with longer, weaker springs might not transfer as much energy to the truck.

cruz-in wrote:

RCMAN46 wrote:

93Cobra2771 wrote:
HA considers the tongue weight it can contain as 1400# on the TT itself. Their literature doesn't say "up to 1400# tongue weight minus the weight of the HA itself". In fact, now that I think about it, I don't recall any hitch manufacturers stating "XXXX tongue weight minus the weight of the hitch".

Your TV cares less whether it it is tongue weight from the TT, or hitch weight from the HA. It is considered weight for all intents and purposes.

[soapbox]Come on, guys, must we nit pic every single post on rv.net to death? This is why people come here and post once, then never post again. Or update their original posts. I'm actually surprised the OP came back, as he has been quite beat to death on his last couple of posts. He is trying to learn, and is doing quite well, IMO. [/soapbox]

To the OP - as others have said, you can't adjust a hitch to make up for a crappy road. Adjusting speed is about all you can do. Sometimes an oscillation effect occurs due to wheelbase and expansion joints. New shocks may slow down those oscillations, then again they may make it worse. Adjusting speed is the easiest way to control them, IMO.

YMMV

Some of us are not nit picking.

Most trailer towing problems are due to insufficient tongue weight.

Several of us have asked how the tongue weight percentage was determined.

That requires a gross weight of the trailer and the tongue weight.

So far we have not got a gross weight of the trailer and the tongue weight given is probably not accurate. But with the way the OP measured it he probably measuring a weight that is greater than actual.

Thanks for the support 93Cobra2771

The above poster is one who seems to particularly enjoy hiding being the anonanimity (sp) of the internet to beat up and bullly folks. To the above poster, here is my post from the previous page:

"Thanks much for taking the time to carefully read my post and respond in a thoughtful manner.

1) I do actually weigh the TW.
2) In making my calculations of TW percentage, I was considering the wieght of the Hensley and support equipment that stays permanently on the TW of the trailer. Just like the propane and batteriens on the tongue.
3) Hensley tells me that (minus the wieght of the Hensley) I should stay at or bleow 1400 TW to be in spec,
4) As the weight of the permanently attached Hensleycomponents is a about 150 pounds, I was are 1550 pounds of TW.
3) 1550/12000 got e to my approximater 13% TW."

I tried to very carefully tell you what I was doing to get to % TW. In prarticular look at the last point (I incorrectly listes as 3)). You will see my GVW of the trailer is 12000.

As your next post/attack will likely be "how did you measure GVW" here is a quote from a few posts up"

"As far as trailer weight, the trailer was weighed once all ready to go...typically travel the same each time..,,,.so I assume it is still in the neighborhood of that original measurement (this was just done last fall)."

Your statement about TW not being accurate is silly and simply more internet bullying on your part.. Following the procedure I followed (and detailerd in the above post) is very acceptable to get witnin a few percent of the true TW.

To all who have been so helpful and taking the time to offerr insights, opinions, and thoughts I extend my sincerest apprecaiation.

I ask that we get this post back on track....

Last I will say about the internet bullying by some on this thread. The objective user can read the thread and make thier own judgement.

You said you weighed the trailer all ready to travel.

What was that weight?

If requesting the scale number is considered bulling then so be it.

I believe I have only asked the OP for two things.

1. The actual gross scale weight of the trailer not manufacture weights.

2. The actual tongue weight. The OP has provided a weight for the tongue but as many have indicated the number given is close but not actual.