Is this a lack of a sway control device issue ?

[currinh]

Floating Cloud:

I hadn't heard this rule of thumb, tongue weight 10-15% of trailer weight. I'm sure it's without the WDH, a hitch weight with the WDH installed in difficult to obtain. Without WDH the trailer is 3600lb and hitch weight is 350lb, very close to 10%.

With the WDH it pulls so well I'm not worried if the hitch is on the little light of this rule. But I'll stop worrying about replacing the 12V battery with two 6V in the front storage box. When we do this it'll add a few pounds to the hitch.

Thanks.

Originally Posted by Floating Cloud

If a trailer weighs 3600 lbs and the tongue weight is 300 lbs with WDH, how is that sufficient.

We always try to have a tongue weight of at least 400 lbs. with similar weight.

[float5]

Yes, 10-15% is the standard recommendation. You do not want to be short on that. Yes, batteries help so another one would be good given your situation. We load a few things inside at the front. I assume you have propane tanks up there. That can help and has even been known to put some people over occasionally.

The common problem though is usually being underweight on the tongue and that is considered by many to be more dangerous than overweight, which is not now a concern judging by your weights.

[Brian B-P]

Originally Posted by currinh

I found GAWR for the 2014 XTerra (ours is a 2013) to be 2676 lb front and 2962 lb rear. I hadn't looked at this before and it means we should be using a WDH.

I agree that the rear axle load is a reason (to me, the only or at least primary reason) to be using WD. The current numbers are fine, but the front axle load is nearly up to GAWR, so if the trailer tongue weight or tug passenger/cargo loading is changed, the axle loads need to be checked and WD may need to be adjusted to keep everything within limits.

[currinh]

Brian:

This makes me question the GAWR weights I found. The XTerra without trailer had a front axle weight of 2550lb and a GAWR of 2675lb. It was not heavily loaded and to be within 125lb of that limit is unreasonable. Two heavy people would push this limit.

Originally Posted by Brian B-P

I agree that the rear axle load is a reason (to me, the only or at least primary reason) to be using WD. The current numbers are fine, but the front axle load is nearly up to GAWR, so if the trailer tongue weight or tug passenger/cargo loading is changed, the axle loads need to be checked and WD may need to be adjusted to keep everything within limits.

Allan:

This is pretty XTerra specific, but applicable to other vehicles. Is this of use to you or have we drifted too far afield?

Thanks.

[thoer]

My primary reason for using our WDH is that it makes the ride much better with our Tacoma, much less porpoising and helps the trailer and tow seem almost like one unit in handling. I've tried it with and without the WDH and much prefer the feel and handling with it on.

Toyota recommending WDH with our year's Tacoma is another factor.

[Brian B-P]

Originally Posted by currinh

This makes me question the GAWR weights I found. The XTerra without trailer had a front axle weight of 2550lb and a GAWR of 2675lb. It was not heavily loaded and to be within 125lb of that limit is unreasonable. Two heavy people would push this limit.

Didn't the Xterra without trailer already have people and cargo in it? Since additional people (in the rear seat) and cargo (in the back) would be much closer to the rear axle than the front, most of the addition would be to the rear axle.

If all of these values are without passengers or cargo in the Xterra, I would be concerned about overloading (front, rear, and total) when they are added.

These GAWR values essentially match those I saw for the second-generation Xterra in other web search matches.


Al's Tacoma should have greater margins, due to the likely greater capacities of the truck and the lower weight of his smaller trailer... but in other discussions in this and other forums it has become clear that even pickups often run into load capacity problems with trailers well under their basic trailer weight limit.

[Brian B-P]

Originally Posted by thoer

My primary reason for using our WDH is that it makes the ride much better with our Tacoma, much less porpoising and helps the trailer and tow seem almost like one unit in handling. I've tried it with and without the WDH and much prefer the feel and handling with it on.

That probably means, in part, that although the rear axle load without WDH may be within the axle's safe load capacity, the suspension is not stiff or well-damped enough for ideal control of the load. I added air bags to our van's rear suspension; this did not increase GAWR, but it does help the ride better and handle the trailer better.

[thoer]

Originally Posted by Brian B-P

That probably means, in part, that although the rear axle load without WDH may be within the axle's safe load capacity, the suspension is not stiff or well-damped enough for ideal control of the load. I added air bags to our van's rear suspension; this did not increase GAWR, but it does help the ride better and handle the trailer better.

Most likely true about the rear springs not being stiff enough.

[Brian B-P]

Hugh, thanks for the data and your calculations.

Originally Posted by currinh

t = 150.5"
h = 54"
b = 107"

I'm puzzled: the wheelbase (symbol "b") is given as 107", but the 2013 Xterra (and all years since 2005) are supposed to have a wheelbase of 110"

Referring to the diagrams and balance equations in Hugh's post #40...
Given the dimensions, I agree with Hugh's calculation approach, which is to balance the sum of vertical forces for each situation, and balance the sum of moments (force times moment arm, or torque) for each situation.

My only concern with the equations is that the moments are not all summed around a consistent reference point. The only way the moments balance is if they are calculated with respect to the same centre of rotation.

In the trailer with WD, the weight is multiplied by "Xt", the hitch weight is multiplied by "t", and the axle load is omitted (mulitplied by the distance to the axle of zero), so they are the moments of the these forces around the axle, but the WD system torque is shown about the ball (as it must be to be equated to the WD system torque on the tow vehicle).
Similarly, the moments for the tow vehicle are summed around the rear axle... except the WD torque.
Both trailer and tow vehicle moment sums could be calculated with respect to the ball, instead, and then the balance equations would be valid.

Hugh, does this make sense?

[currinh]

Brian:

You are correct. We were loaded the same as for the trip. However, we aren't at the top of the weight tables, particularly my wife, so a large driver and large passenger would likely be over the limit. Otherwise, most weight was near the rear axle, two dogs totalling 130lb and ice chest & water in the back. We weren't loaded that heavily.

Originally Posted by Brian B-P

Didn't the Xterra without trailer already have people and cargo in it? Since additional people (in the rear seat) and cargo (in the back) would be much closer to the rear axle than the front, most of the addition would be to the rear axle.

[currinh]

Brian:

Originally Posted by Brian B-P

I'm puzzled: the wheelbase (symbol "b") is given as 107", but the 2013 Xterra (and all years since 2005) are supposed to have a wheelbase of 110"

Could well be off a few inches. The other two need to be measured, particularly the rear tire contact to hitch ball, so I just measured all three.

Originally Posted by Brian B-P

Referring to the diagrams and balance equations in Hugh's post #40... Given the dimensions, I agree with Hugh's calculation approach, which is to balance the sum of vertical forces for each situation, and balance the sum of moments (force times moment arm, or torque) for each situation.

My only concern with the equations is that the moments are not all summed around a consistent reference point. The only way the moments balance is if they are calculated with respect to the same centre of rotation.

In the trailer with WD, the weight is multiplied by "Xt", the hitch weight is multiplied by "t", and the axle load is omitted (mulitplied by the distance to the axle of zero), so they are the moments of the these forces around the axle, but the WD system torque is shown about the ball (as it must be to be equated to the WD system torque on the tow vehicle).
Similarly, the moments for the tow vehicle are summed around the rear axle... except the WD torque. Both trailer and tow vehicle moment sums could be calculated with respect to the ball, instead, and then the balance equations would be valid.

Hugh, does this make sense?

Thanks for looking at these.

I believe in the sum of the moments, torque, equations an applied moment can float or be applied anywhere for the same effect. Summing moments about the trailer ball we get the same results.